Sentencia super Meteora

COMMENTARY ON
ARISTOTLE'S
METEOROLOGY

by

Thomas Aquinas

Aristotle translated by E. W. Webster
Aquinas translated by Pierre Conway, O.P. and F.R. Larcher, O.P., 1964
html by Joseph Kenny OP

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CONTENTS

BOOK I

1. Aristotle's intent in this book. Enumeration of ground previously covered in preceding books, and yet to be covered in subsequent books
2. Principles of the natural changes to be considered in this book. Their relations to each other
3. Mutual transformation of the elements. Presence above of the heavenly body
4. Three questions. The first, on the order of the elements is solved
5. The remaining two questions solved
6. Shooting stars and meteors — cause and difference
7. Solution of problems concerning shooting stars
8. Cause of other phenomena appearing at night, and of certain that do not
9. The opinions of others concerning comets
10. Refutation of these opinions
11. Cause, time and place of the appearance of comets according to Aristotle
12. Opinions of others on the Milky Way
13. The Milky Clay, according to Aristotle
14. Causes in general of phenomena generated by the moist exhalation in lower part of the air. Of rain, dew and frost
15. The place of the generation of hail and snow
16. The cause of the generation of rivers
17. The duration and change of rivers

BOOK II

1. Opinions of ancients on origin of sea and its saltness
2. The sea is shown to be the natural place of all water
3. Why the sea does not increase. Rejection of Plato's Tartarus
4. Whether the sea always was, and always will be
5. Saltness of the sea according to opinions of others
6. Cause of the sea's saltness according to Aristotle
7. On the generation of winds
8. On the local motion of the winds
9. On the increase and diminishing of winds
10. South wind not from antarctic but from summer tropic
    by unknown author:
11. De ordine et contrietate ventorum
12. De quibusdam accidentibus et effectibus ventorum
    by Thomas Aquinas:
13. Improbantur quaedam opiniones de terraemotu
14. Principium terraemotus iuxta Philosophum
15. De accidentibus consequentibus terraemotum et differentiis eius
    by unknown author:
16. Quomodo generentur tonitruum et cvoruscatio
17. Opiniones aliorum de coruscatione et tonitruo refutantur

BOOK III

by unknown author:

1. De ecnephia et typhone
2. De incensione et fulmine
3. De quibusam accidentibus circa halo, iridem, prelios et virgas
4. De halo
5. De generatione colorum iridis in generali, de colore puniceo
6. Absolvitur quaestio de coloribus iridis, quaestiones circa iridem
7. De figura et quibusdam aliis accidentibus iridis
8. De virgis et pareliis
9. De fossibus et metallicis

BOOK IV

by unknown author

1. Prooemium
2. De operationibus qualitatum activarum in mixto
3. De digestione et indigestione
4. De speciebus digestionis et indigestionis, de pepansi et omote
5. De hepensi et molynsi
6. De opsesi et stateusi
7. De quimis qualitatibus passivis corporum, de duro et molli
8. Quomodo quaenam siccantur et humectantur
9. De quibusdam speciebus qualitatum passivarum
10. Quae et quot sint species qualitatum passivarum
11. De iisdem
12. De iisdem
13. De iisdem
14. De qualitatibus passivis per comparationem ad corpora
15. De qualitatibus activis per comparationem ad corpora
16. De corporibus homoeomeris per comparationem ad passiones praedictas

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Α
BOOK I

Lecture 1 Aristotle's intent in this book. Enumeration of ground previously covered in preceding books, and yet to be covered in subsequent books.
Chapter 1
(338a.) Περὶ μὲν οὖν τῶν πρώτων αἰτίων τῆς φύσεως καὶ περὶ πάσης κινήσεως φυσικῆς, ἔτι δὲ περὶ τῶν κατὰ τὴν ἄνω φορὰν διακεκοσμημένων ἄστρων καὶ περὶ τῶν στοιχείων τῶν σωματικῶν, πόσα τε καὶ ποῖα, καὶ τῆς εἰς ἄλληλα μεταβολῆς, καὶ περὶ γενέσεως καὶ φθορᾶς τῆς κοινῆς εἴρηται πρότερον.	1 We have already discussed the first causes of nature, and all natural motion, also the stars ordered in the motion of the heavens, and the physical element-enumerating and specifying them and showing how they change into one another—and becoming and perishing in general.
λοιπὸν δ' ἐστὶ μέρος τῆς μεθόδου ταύτης ἔτι θεωρητέον, ὃ πάντες οἱ πρότεροι μετεωρολογίαν ἐκάλουν	2 There remains for consideration a part of this inquiry which all our predecessors called meteorology.
ταῦτα (338b.) δ' ἐστὶν ὅσα συμβαίνει κατὰ φύσιν μέν, ἀτακτοτέραν μέντοι τῆς τοῦ πρώτου στοιχείου τῶν σωμάτων, περὶ τὸν γειτνιῶντα μάλιστα τόπον τῇ φορᾷ τῇ τῶν ἄστρων, οἷον περί τε γάλακτος καὶ κομητῶν καὶ τῶν ἐκπυρουμένων καὶ κινουμένων φασμάτων,	3 It is concerned with events that are natural, though their order is less perfect than that of the first of the elements of bodies. They take place in the region nearest to the motion of the stars. Such are the milky way, and comets, and the movements of meteors.
ὅσα τε θείημεν ἂν ἀέρος εἶναι κοινὰ πάθη καὶ ὕδατος,	4 It studies also all the affections we may call common to air and water,
ἔτι δὲ γῆς ὅσα μέρη καὶ εἴδη καὶ πάθη τῶν μερῶν, ἐξ ὧν περί τε πνευμάτων καὶ σεισμῶν θεωρήσαιμεν ἂν τὰς αἰτίας (339a.) καὶ περὶ πάντων τῶν γιγνομένων κατὰ τὰς κινήσεις τὰς τούτων ἐν οἷς τὰ μὲν ἀποροῦμεν, τῶν δὲ ἐφαπτόμεθά τινα τρόπον	5 and the kinds and parts of the earth and the affections of its parts. These throw light on the causes of winds and earthquakes and all the consequences the motions of these kinds and parts involve. Of these things some puzzle us, while others admit of explanation in some degree.
ἔτι δὲ περὶ κεραυνῶν πτώσεως καὶ τυφώνων καὶ πρηστήρων καὶ τῶν ἄλλων τῶν ἐγκυκλίων, ὅσα διὰ πῆξιν συμβαίνει πάθη τῶν αὐτῶν σωμάτων τούτων.	6 Further, the inquiry is concerned with the falling of thunderbolts and with whirlwinds and fire-winds, and further, the recurrent affections produced in these same bodies by concretion.
διελθόντες δὲ περὶ τούτων, θεωρήσωμεν εἴ τι δυνάμεθα κατὰ τὸν ὑφηγημένον τρόπον ἀποδοῦναι περὶ ζῴων καὶ φυτῶν, καθόλου τε καὶ χωρίς σχεδὸν γὰρ τούτων ῥηθέντων τέλος ἂν εἴη γεγονὸς τῆς ἐξ ἀρχῆς ἡμῖν προαιρέσεως πάσης.	7 When the inquiry into these matters is concluded let us consider what account we can give, in accordance with the method we have followed, of animals and plants, both generally and in detail. When that has been done we may say that the whole of our original undertaking will have been carried out.

Sicut in rebus naturalibus nihil est perfectum dum est in potentia, sed solum tunc simpliciter perfectum est, quando est in ultimo actu; quando vero medio modo se habens fuerit inter puram potentiam et purum actum, tunc est quidem secundum quid perfectum, non tamen simpliciter; sic et circa scientiam accidit. Scientia autem quae habetur de re tantum in universali, non est scientia completa secundum ultimum actum, sed est medio modo se habens inter puram potentiam et ultimum actum. Nam aliquis sciens aliquid in universali, scit quidem aliquid eorum actu quae sunt in propria ratione eius: alia vero sciens in universali non scit actu, sed solum in potentia. Puta, qui cognoscit hominem solum secundum quod est animal, solum scit sic partem definitionis hominis in actu, scilicet genus eius: differentias autem constitutivas speciei nondum scit actu, sed potentia tantum. Unde manifestum est quod complementum scientiae requirit quod non sistatur in communibus, sed procedatur usque ad species: individua enim non cadunt sub consideratione artis; non enim eorum est intellectus, sed sensus.	1. Just as in natural things nothing is perfect so long as it is in potency, but is perfect absolutely only when it is in ultimate act, and just as, when it is midway between pure potency and pure act, it is perfect in a qualified sense but yet not absolutely so too with science. Now the science which one has of a thing only in a universal way is not science complete according to ultimate act, but is midway between pure potency and ultimate act. For someone who knows something in a universal way, does indeed know something in act of the things that are included in its proper notion; but he who thus knows in a universal way, knows other things, not actually, but in potency only. For example, one who knows man only accordingly as he is animal, thus knows in act only a part of the definition of man, namely, the genus; but the differences constitutive of the species he does not yet know in act but potentially only. Consequently, it is plain that the completion of science requires that one not stop at what is common but go on to the species (individuals not falling under the consideration of art, since of them there is not intellectual understanding but sense knowledge).
Quia igitur Aristoteles in libro de generatione determinavit de transmutationibus elementorum in communi, necessarium fuit ad complementum scientiae naturalis, determinare de speciebus transmutationum quae accidunt circa elementa: et de his determinat in hoc libro, qui intitulatur Meteorologicorum.	2. For this reason, since Aristotle in the book, On Generation, has determined concerning the transmutation of elements in common, it was necessary, for the completion of natural science, to determine concerning the species of transmutations that affect the elements. And he determines concerning these in this book, entitled Meteorology.
Est igitur intentio eius in hoc libro determinare de transmutationibus quae accidunt circa elementa, secundum singulas species. Et ad manifestandam suam intentionem, praemittit prooemium. In quo tria facit:	It is his intention, therefore, in this book to determine concerning the transmutations that occur with respect to the elements, according to their several species. And in order to indicate his intention he presents an introduction, in which he does three things:
primo enim enumerat ea de quibus tractatum est in libris scientiae naturalis praecedentibus hunc librum; secundo manifestat de quibus in hoc libro sit agendum, ibi: reliqua autem pars huius etc.; tertio ostendit de quibus in sequentibus libris restat agendum, ibi: pertranseuntes autem de his et cetera.	First, he enumerates the things already treated in the books of natural science that precede this book, at 3; Secondly, he shows what is to be treated in this book, at 4; Thirdly, he shows what remains to be discussed in books that follow, at 9.
Praecedunt autem hunc librum, secundum ordinem, in scientia naturali tres libri. Unde tria facit.	3. Three books precede the present one, according to order, in natural science. Hence he does three things [1].
Primo ponit de quo sit actum in libro physicorum. In quo quidem, quantum ad duos primos libros eius, agitur de causis naturae: et hoc tangit, concludens ex determinatione praecedentium librorum, cum dicit: de primis quidem igitur causis naturae; ut intelligantur primae causae naturae prima principia, quae sunt materia, forma et privatio, et etiam quatuor genera causarum, scilicet materia, forma, agens et finis, in sequentibus autem libris physicorum agitur de motu in generali: et hoc est quod subdit: et de omni motu naturali.	First, he states what was treated in the book of Physics. As to the first two books, it is question of the causes of nature. This he alludes to, concluding from what has been determined in the books preceding [The Meteorology], when he says: "We have already spoken about the first causes of nature," meaning by "first causes of nature," the first principles, which are matter, form and privation, as well as the four genera of causes, namely, matter, form, agent and end. In the subsequent books of the Physics the discussion is of motion in general; hence he adds, "and of every natural motion."
Secundus scientiae naturalis liber est liber de caelo et mundo. In cuius prima parte, scilicet in duobus eius primis libris, agitur de caelo et stellis, quae moventur motu circulari: et quantum ad hoc dicit: adhuc autem de secundum superiorem lationem perornatis astris; perornatis, idest valde ornate dispositis, secundum superiorem lationem, idest secundum motum circularem, quo moventur omnia corpora caelestia. In secunda autem parte huius libri, scilicet tertio et quarto libro, determinat de numero elementorum et de motu locali eorum: et quantum ad hoc dicit: et de elementis corporalibus, quot et quae sint. Dicit autem elementa corporalia, ad differentiam primorum principiorum, scilicet materiae et formae, quae non sunt corpora, sed corporum elementa seu principia: ignis autem et aqua et terra corpora sunt, et sunt aliorum corporum elementa.	The second book of natural science is the book, On the Heavens, in the first part of which, i.e., in its first two books, the discussion is about the heaven and the stars, which are moved with circular motion. This he alludes to when he says: "We have also discussed the superior movement of the well-appointed stars," meaning by "well-appointed," very beautifully arranged, and by "as to their superior motion," the circular motion by which all the heavenly bodies are moved. In the second part of that book, i.e. in the third and fourth books, he determines concerning the number of elements and their local motion. Alluding to this he says: "and about the bodily elements we have discussed their number and nature." He says "bodily" elements to distinguish them from the first principles, namely, matter and form, which are not bodies but the elements or principles of bodies, whereas fire and water and earth are bodies, and are the elements of other bodies.
Tertius liber scientiae naturalis est liber de generatione: in quo determinat de permutatione elementorum in invicem, in secundo libro, et de generatione et corruptione in communi in primo libro. Et hoc tangit consequenter, cum dicit: et de ea quae invicem et cetera.	The third book of natural science is the book, On Generation, wherein are treated the mutual transmutation of elements, in the second book; and generation and corruption in common, in the first book. This he subsequently alludes to when he says: "and of things that are mutually transmutable."
Deinde cum dicit: reliqua autem pars huius etc., manifestat de quo sit in hoc agendum. Et circa hoc duo facit:	4. Then [2] he shows what is to be discussed in the present book. About this he does two things:
primo ponit nomen consuetum huius doctrinae; secundo enumerat ea quae in hac doctrina continentur.	First, he gives the usual name for this body of doctrine, at 4; Secondly, he enumerates the things contained in this doctrine, also at 4.
Dicit ergo primo quod reliqua pars huius methodi, idest scientiae naturalis, quam prae manibus habemus, restat adhuc consideranda, quam omnes priores philosophi vocabant meteorologiam, a meteoron, quod est excelsum vel elevatum, et logos, quod est sermo vel ratio: considerantur enim in hac doctrina ea quae in excelsis generantur, sicut stellae cadentes, stellae cometae, pluviae, nives, et alia huiusmodi. Quamvis et alia quaedam considerentur quae fiunt in imo, sicut fulmina, terraemotus, et alia huiusmodi: sed quia ea quae fiunt in alto, sunt mirabiliora et magis desiderata, ideo ab eis tota doctrina nomen accepit.	He says therefore first that the remaining part of "this method," i.e. of natural science, which we have before us, is still to be treated. [What is now to be considered] is what all the earlier philosophers called "meteorology" - from meteoron which means "on high" or "elevated," and from logos, which is a "statement" or "explanation" - for in it are considered the things generated on high, such as falling stars, comets, rain, snow, and so on. This does not mean that other things, produced in the lower regions, such as lightning, earthquakes and the like, will not be discussed; but, because things generated on high are more marvelous and more desired, it is from them that this whole doctrine takes its name.
Secundo ibi: haec autem sunt etc., enumerat ea de quibus in hac doctrina consideratur. Quae videntur in quatuor distingui. Quaedam enim sunt quae fiunt in loco supremo propinquo corpori caelesti: et haec primo tangit, cum dicit: haec autem sunt, scilicet de quibus adhuc restat considerandum, quaecumque accidunt quidem secundum naturam, sed inordinatam, et casualiter, ut quidam putabant. Natura tamen inordinatior non est natura illa quae est primi elementi corporum, idest corporis caelestis; quod dicitur elementum, quia est pars totius universi corporalis, licet non veniat in compositionem corporis mixti, sicut elementa. Est autem natura secundum quam haec accidunt, inordinatior natura caelestis corporis: quia ea quae sunt in caelesti corpore, semper similiter se habent, in huiusmodi autem transmutationibus inferiorum corporum, accidit multa varietas. Propter quam quidam crediderunt quod haec non a natura, sed a casu acciderent, non considerantes quod naturaliter fiunt non solum ea quae sunt semper, sed etiam quae sunt ut in pluribus. Haec, inquam, accidunt circa locum maxime propinquum lationi astrorum, idest astris circulariter motis. Et hoc ponit ad differentiam subsequentium. Et exemplificat, dicens: puta de lacte, idest de lacteo circulo qui Galaxia dicitur, et stellis quae cometae dicuntur, et phantasmatibus, idest apparitionibus, ignitis et motis, quae dicuntur stellae cadentes.	5. Secondly [3] he enumerates the things to be considered in this doctrine. These are seen to be divided into four groups. For there are some things that are produced in the highest region, nearest to the heavenly body. Such things are, namely, those concerning which it still remains to be considered, things that happen indeed according to nature, but not an ordered nature and, as some claimed, by chance. This more irregular nature is not, however, the nature which belongs to the "first element of bodies," i.e., the celestial body, called "element," because it is a part of the whole corporeal universe, although it does not enter into the composition of mixed bodies, as do the elements. The nature according to which these things occur is more unordered than the nature of the celestial body, since the things in the celestial body always behave in the same way, whereas in the transmutations affecting the lower bodies much variation occurs. It was on this account that some have believed that these occurred, not by nature, but by chance, failing to consider that there is produced by nature, not only those things which happen always, but also those which happen for the most part. These, I say, occur in the region nearest the "carrying of the stars," i.e., the stars that are circularly moved. This he sets down to distinguish them from those that follow. As an example he mentions the "Milk," i.e., the milky circle called the "galaxy," and the stars called "comets," and the "phantoms," i.e. the apparitions, fiery and moving, called "falling stars" [meteors].
Secundo cum dicit: et quaecumque ponemus etc., enumerat ea quae sub praedictis fiunt; scilicet quaecumque ponuntur esse passiones communes aeris et aquae, quia ex materia aquea in loco aeris generantur, vaporibus in aquam transmutatis.	6. Secondly [4], he enumerates the things which take place under the foregoing; namely, all things that are posited as phenomena common to air and water - for they are produced from aqueous matter in the region of air, when vapors are changed into water.
Tertio cum dicit: adhuc autem terrae etc., enumerat ea quae in infimo sunt. Et dicit: adhuc autem oportet dicere de his quae sunt partes terrae, puta oriens, occidens, Septentrio, meridies; et quae sunt species, puta quod quaedam terra est calida et arenosa, quaedam frigida et calcata; et passiones partium terrae, puta quod quaedam est sulphurea, quaedam lapidosa, vel aliquo modo dissoluta. Ex quibus terrae rationibus considerabimus omnes causas spirituum, idest ventorum, quorum differentia attenditur secundum diversitatem terrae. Similiter de terraemotibus, quorum etiam causae assignantur ex diversa specie terrae; et de omnibus quae fiunt secundum motus horum, idest ventorum et terraemotuum. In quibus non omnia perfecte et secundum certitudinem tradere possumus, sed quaedam sub dubitatione relinquemus, ad utramque partem rationem inducentes: in quibusdam vero veritatem attingemus aliquo modo.	7. Thirdly [5], he enumerates what takes place in the lowest region and says: "We must also talk about the parts of the earth," such as east, west, north, south, "and about its kinds," for example, that some earth is hot and sandy, and some cold and compact, "and about the properties of the parts" of the earth, for example, that some are sulphurous, some stony or in some way broken up. "From this knowledge" of the earth "we shall consider all the causes of "spirits," i.e., winds, that differ according to the difference of the earth. Likewise, "of earthquakes," the causes of which are attributed to the different type of earth, "and of all things that take place according to the motions of these," i.e., of winds and earthquakes. In these matters we cannot explain everything perfectly and according to certitude, but shall let some things remain doubtful, giving reasons for both sides; but in others we shall to some degree reach the truth.
Quarto ibi: adhuc autem de fulminum casu etc., enumerat ea quae ex alto in infimum descendunt, ex ventis causata, dicens: adhuc autem dicemus de casu fulminum et typhonibus (qui dicuntur siphones), et incensionibus quae circa huiusmodi typhones accidunt, et aliis circularibus, quaecumque propter coagulationem accidunt passiones ipsorum corporum, scilicet elementorum. Dicit autem hoc, quia typhones ex materia compacta generantur cum quadam rotatione; et multa alia similia accidunt typhonibus, ex materia coagulatione compacta, cum quadam circulatione. Vel potest hoc referri ad iridem et halonem (idest circulum continentem solem et lunam et stellas), quae accidunt ex reverberatione radiorum ad aliquam materiam spissam.	8. Fourthly [6], he enumerates the things which descend from on high as the result of winds. He says, therefore, that we shall also give an account of the falling of thunderbolts, and of whirlwinds (called "siphons") and of the burnings that accompany such whirlwinds, and of other circular phenomena that occur from congealing and are properties of those bodies, namely, the elements. He says this because whirlwinds are generated from compacted matter set rotating, and many other like things happen to whirlwinds as a result of matter compacted and set in circular motion. Or this could refer to the rainbow and halo (i.e., the corona surrounding the sun and moon and stars) which result from rays rebounding from thick matter.
Deinde cum dicit: pertranseuntes autem de his etc., ponit de quo restat agendum in libris sequentibus. Et dicit quod postquam pertransiverimus de his quae dicta sunt, tunc speculabimur, secundum nostrum posse, modo inducto in libris praecedentibus, scilicet non tantum recitando opiniones aliorum sed etiam causas inquirendo, de animalibus et plantis, et in universali et secundum singulas species. Et tunc fere erit finis scientiae naturalis, quam a principio elegimus tradere. Dicit autem fere, quia non omnia naturalia ab homine cognosci possunt.	9. Then at [7] he mentions what remains to be treated in the books to follow and says that after we shall have finished with these matters enumerated above, we shall to the best of our ability, according to the method employed in earlier books (i.e., not by merely reciting others' opinions, but by inquiring into causes, speculate about animals and plants, both in a universal way and according to the individual species. And that will be almost the end of the natural science which we chose to discuss from the beginning. He says "almost," because not all natural things can be known by man.

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Lecture 2 Principles of the natural changes to be considered in this book. Their relations to each other
Chapter 1 cont.
ὧδ' οὖν ἀρξάμενοι λέγωμεν περὶ αὐτῶν πρῶτον.	After this introduction let us begin by discussing our immediate subject.
Chapter 2
ἐπειδὴ γὰρ διώρισται πρότερον ἡμῖν μία μὲν ἀρχὴ τῶν σωμάτων, ἐξ ὧν συνέστηκεν ἡ τῶν ἐγκυκλίως φερομένων σωμάτων φύσις, ἄλλα δὲ τέτταρα σώματα διὰ τὰς τέτταρας ἀρχάς, ὧν διπλῆν εἶναί φαμεν τὴν κίνησιν, τὴν μὲν ἀπὸ τοῦ μέσου τὴν δ' ἐπὶ τὸ μέσον τεττάρων δ' ὄντων τούτων, πυρὸς καὶ ἀέρος καὶ ὕδατος καὶ γῆς, τὸ μὲν τούτοις πᾶσιν ἐπιπολάζον εἶναι πῦρ, τὸ δ' ὑφιστάμενον γῆν δύο δὲ ἃ πρὸς αὑτὰ τούτοις ἀνάλογον ἔχει (ἀὴρ μὲν γὰρ πυρὸς ἐγγυτάτω τῶν ἄλλων, ὕδωρ δὲ γῆς) ὁ δὴ περὶ τὴν γῆν ὅλος κόσμος ἐκ τούτων συνέστηκε τῶν σωμάτων περὶ οὗ τὰ συμβαίνοντα πάθη φαμὲν εἶναι ληπτέον.	We have already laid down that there is one physical element which makes up the system of the bodies that move in a circle, and besides this four bodies owing their existence to the four principles, the motion of these latter bodies being of two kinds: either from the centre or to the centre. These four bodies are fire, air, water, earth. Fire occupies the highest place among them all, earth the lowest, and two elements correspond to these in their relation to one another, air being nearest to fire, water to earth. The whole world surrounding the earth, then, the affections of which are our subject, is made up of these bodies.
ἔστιν δ' ἐξ ἀνάγκης συνεχὴς οὗτος ταῖς ἄνω φοραῖς, ὥστε πᾶσαν αὐτοῦ τὴν δύναμιν κυβερνᾶσθαι ἐκεῖθεν ὅθεν γὰρ ἡ τῆς κινήσεως ἀρχὴ πᾶσιν, ἐκείνην αἰτίαν νομιστέον πρώτην.	9 This world necessarily has a certain continuity with the upper motions: consequently all its power and order is derived from them. (For the originating principle of all motion is the first cause.
πρὸς δὲ τούτοις ἡ μὲν ἀίδιος καὶ τέλος οὐκ ἔχουσα τῷ τόπῳ τῆς κινήσεως, ἀλλ' ἀεὶ ἐν τέλει ταῦτα δὲ τὰ σώματα πάντα πεπερασμένους διέστηκε τόπους ἀλλήλων. ὥστε τῶν συμβαινόντων περὶ αὐτὸν πῦρ μὲν καὶ γῆν καὶ τὰ συγγενῆ τούτοις ὡς ἐν ὕλης εἴδει τῶν γιγνομένων αἴτια χρὴ νομίζειν (τὸ γὰρ ὑποκείμενον καὶ πάσχον τοῦτον προσαγορεύομεν τὸν τρόπον), τὸ δ' οὕτως αἴτιον ὅθεν ἡ τῆς κινήσεως ἀρχή, τὴν τῶν ἀεὶ κινουμένων αἰτιατέον δύναμιν.	10 Besides, that element is eternal and its motion has no limit in space, but is always complete; whereas all these other bodies have separate regions which limit one another.) So we must treat fire and earth and the elements like them as the material causes of the events in this world (meaning by material what is subject and is affected), but must assign causality in the sense of the originating principle of motion to the influence of the eternally moving bodies.

Completo prooemio, in quo philosophus suam intentionem manifestavit, hic incipit procedere ad suum propositum ostendendum. Et dividitur in duas partes:	10. Having completed an introduction, in which the Philosopher has revealed his intention, he now begins to show his proposition. And this is divided into two parts:
in prima resumit ea quae sunt necessaria ad cognoscendum principia transmutationum de quibus in hoc libro tractaturus est; in secunda incipit de eis tractare, ibi: resumentes igitur eas et cetera.	In the first he restates facts necessary for knowing the principles of the transmutations to be treated in this book, at 11; In the second part he begins to treat of them (L. 3).
Circa primum duo facit:	About the first he does two things:
primo enumerat principia harum transmutationum, et differentiam eorum adinvicem; secundo ostendit quomodo se habeant adinvicem in causando, ibi: est autem ex necessitate continuus et cetera.	First, he enumerates the principles of these transmutations and their difference from one another, at 11; Secondly, he shows how they are related to one another in causing, at 12.
Dicit ergo primo quod prius determinatum est, tam in libro de caelo quam in libro de generatione, quod inter alia principia corporalia quae sunt principia aliorum corporum, unum est principium illorum corporum ex quibus constituitur natura corporum circulariter motorum, scilicet sphaerarum et stellarum: hoc autem principium dicit ipsam quintam essentiam, ex quo omnia huiusmodi formantur. Alia vero principia corporum inferiorum sunt quatuor, propter primas tangibiles qualitates, quae sunt principia agendi et patiendi, scilicet calidum, frigidum, humidum et siccum, quarum sunt tantum quatuor possibiles combinationes: nam calidum et siccum est ignis, calidum et humidum est aer, frigidum et humidum aqua, frigidum et siccum terra; calidum vero et frigidum, vel humidum et siccum aliquid esse, impossibile est.	11. He says therefore first [8] that it has been previously determined both in the book, On the Heavens, and in the book, On Generation, that among the other corporeal principles that are principles of other bodies there is one which is the principle of those bodies from which is constituted the nature of the bodies circularly moved, i.e., of spheres and stars. This principle, out of which all such bodies are formed, he calls the "fifth essence." The other principles, of the lower bodies, are four in number, because of the primary tangible qualities, which are the principles of acting and of being acted upon. These are the hot, cold, moist and dry, of which there are but four possible combinations: for the hot and dry is fire, the hot and moist is air, the cold and moist is water, and the cold and dry is earth (that something should be hot and cold, or moist and dry, is impossible).
Horum autem quatuor corporum sunt duo motus: unus quidem qui est a medio mundi sursum, qui est motus levium, scilicet ignis et aeris; alius autem motus est ad medium, qui est motus gravium, scilicet terrae et aquae. Et sic est triplex motus corporum: scilicet ad medium, qui est gravium; a medio, qui est levium; et circa medium, qui est corporum caelestium, quae neque sunt gravia neque levia.	Of these four bodies there are two motions: one is upward from the middle [center] of the world, and this is the motion of light things, namely, fire and air; the other is to the middle [center], and this is the motion of heavy things, namely, earth and water. Accordingly, bodily motions are threefold: namely, to the middle for heavy bodies; from the middle for light bodies; and about the middle for the heavenly bodies, which are neither heavy nor light.
Levium autem et gravium est quaedam differentia. Nam aliquid est leve simpliciter, scilicet ignis, qui supereminet omnibus; aliquid autem est grave simpliciter, scilicet terra, quae subsidet omnibus; alia vero duo sunt secundum quid gravia et levia: nam aer est levis respectu terrae et aquae, gravis vero respectu ignis; aqua autem est levis respectu terrae, gravis autem respectu ignis et aeris. Et ideo haec duo ad alia duo extrema proportionaliter se habent, ut scilicet sicut aer est propinquior igni, ita aqua est propinquior terrae. Sic igitur patet quod iste mundus qui est circa terram, constat ex quatuor corporibus: et huius mundi oportet nos in hoc libro passiones considerare, quae sunt transmutationes variae in elementis inventae.	But notice should be taken of the differences in light and heavy. For there is something which is absolutely light, namely, fire, which is above all the others; there is something which is absolutely heavy, namely, earth, which is under all the others. But the other two are in a certain respect heavy and light — for air is light in relation to earth and water, but heavy in relation to fire; water, on the other hand, is light with respect to earth, but heavy with respect to air and fire. Consequently, these two are proportional to the other two that are extremes, i.e., as air is nearer to fire, so water is nearer to earth. Thus it is plain that the universe around the earth consists of four bodies. This is the world chose passions — which are the various transmutations found in the elements — we must consider in this book.
Deinde cum dicit: est autem ex necessitate continuus etc., ostendit quomodo principia praedicta se habeant adinvicem in causando. Et dicit quod necessarium est quod iste mundus inferior consistat ex quatuor elementis, sic continuatis superioribus lationibus, idest corporibus circulariter motis: continuum autem hic accipit pro contiguo, ut scilicet nihil sit medium inter ea. Cuius quidem necessitatis ratio est, non solum quia impossibile est locum vacuum esse, unde corpora oportet corporibus contiguari: sed etiam propter finem, ut scilicet tota virtus inferioris mundi gubernetur a superioribus corporibus, quod non esset nisi se tangerent; oportet enim quod agens corporale tangat passum et motum ab ipso.	12. Then [9] he shows how the aforesaid principles are related to one another in causing. And he says that it is necessary for the lower world to consist of the four elements thus in continuity with the "upper movements," i.e., with the bodies circularly moved (by "continuous" he here means "contiguous," in the sense that nothing lies between them). The reason why this is necessary is not only because no empty place can exist (hence bodies must be contiguous to bodies), but also because the end requires it — the end being that the whole power of the lower world be governed by the superior bodies, and this would not be, unless they touched — for a bodily agent must touch the thing acted upon and moved by it.
Quod autem inferior mundus regatur a superioribus corporibus et moveatur, probat duabus rationibus. Quarum prima talis est. Causa movens, unde scilicet est principium motus, necesse est quod sit prima causa. Et hoc intelligitur per respectum ad causam formalem et materialem: nam materia patitur ab agente, agens autem naturaliter est prius patiente; forma etiam est effectus moventis, qui educit materiam de potentia in actum. Sed finis est prior agente, quia movet agentem: non tamen semper est prior in esse, sed solum in intentione. Manifestum est autem corpus caeleste inter naturalia esse primam causam: quod eius incorruptibilitas et nobilitas demonstrat. Oportet igitur quod corpus caeleste, respectu horum corporum inferiorum, sit causa unde principium motus.	13. That the lower world is ruled and moved by the superior bodies he proves with two arguments. The first is this: The movent cause, i.e., the originative principle of motion, is necessarily the first cause. (This is to be understood in its relation to the formal and material cause. For matter is acted upon by the agent, which is by nature prior to the patient. The form, too, is an effect of the movent, which educes matter from potency to act. But the end is prior to the agent, because it moves the agent. Yet it is not always prior in the order of existence, but [sometimes] only in the order of intention.) Now it is plain that in the sphere of natural things the heavenly body is the first cause, and this is proved from its incorruptibility and nobility. Consequently, the heavenly body, with respect to these lower bodies, must be the originative cause of motion.
Secundam rationem ponit ibi: adhuc autem etc.: quae talis est. Motus caelestis corporis est perpetuus. Et hoc apparet ex ipsa dispositione loci: nam in linea recta est accipere finem in actu, scilicet extremum ipsius lineae, in circulo vero non est accipere finem: et ideo dicit quod motus circularis non habet finem secundum locum. Et ne aliquis crederet propter hoc, quod motus circularis esset imperfectus, sicut motus rectus antequam perveniat ad finem, subiungit quod motus circularis semper est in fine: quodlibet enim signum datum in circulo est principium et finis; et motus circularis in qualibet parte ita est perfectus, sicut motus rectus quando est in fine. Sic igitur apparet ex ipsa dispositione loci, quod motui caelesti competit perpetuitas.	14. At [10] he gives the second argument, which is this: The motion of the heavenly body is perpetual. This is apparent from the very disposition of place: for in the case of a straight line, one arrives at an end in act, namely, the terminus of the line, but in the case of a circle, one does not arrive at an end. He says, therefore, that circular motion does not have an end according to place. And lest anyone conclude from this that circular motion is imperfect, on the same ground that a straight motion is imperfect before reaching its end, he adds that a circular motion is always at an end — for any point you designate on a circle is both a beginning and an end, and circular motion is as perfect at any sector as a straight motion is at its end. Therefore it is plain, from the very disposition of place, that, to heavenly motions, perpetuity is congruent.
Motus autem inferiorum corporum non possunt esse perpetui: quia inferiora corpora moventur motibus rectis, motus autem rectus non durat unus continuus nisi secundum mensuram magnitudinis rectae per quam transit; motus autem reflexus non est continuus, ut in VIII Physic. probatum est. Unde cum omnia corpora inferiora distent finitis locis abinvicem, et nullum eorum sit infinitum, ut probatum est in III Physic. et in I de caelo, necesse est quod motus eorum sint finiti, et non perpetui. Illud autem quod est perpetuum et semper, consequenter est motivum eorum quae non sunt semper. Unde elementa inferiora, scilicet ignem et terram et alia syngenea his, idest congenerabilia eis, scilicet aerem et aquam, et quae ex eis componuntur, oportet putare causas accidentium circa ipsum mundum inferiorem, ut in specie materiae, idest per modum causae materialis: quia hoc modo dicimus subiectum et patiens esse causam rerum. Sed quod est causa dictorum ut unde principium motus, idest per modum causae moventis, causandum est, idest existimandum est esse causam, eam virtutem quae est semper motorum, idest corporum caelestium, quae semper moventur: quod enim semper movetur, comparatur ad id quod non semper movetur, sicut agens ad patiens.	The motions of lower bodies, on the other hand, cannot be perpetual, because such bodies are moved with rectilinear motions, and a rectilinear motion remains one and continuous only according to the measure of the rectilinear magnitude along which the motion passes, and a reflected motion is not continuous, as was proved in Physics VIII. Hence, since all the lower bodies are a finite distance from one another, and no such body is infinite, as was proved in Physics III and in On the Heavens I, their motions must be finite and not perpetual. What is perpetual and always, consequently, is the movent of those things which are not always. Wherefore the lower elements, namely, fire and earth and the others which are "syngeneous," i.e., congenerable, with them, namely, air and water, and those things which are composed out of them, must be reckoned the causes of the things occurring in the lower world, "in the line of matter," i.e., after the manner of the material cause, because that is the way we speak of a subject and a patient being a cause of things. But their cause in the sense of "originative source of motion," i.e., their cause after the manner of movent cause, must be "sustained," i.e., held, to be that power which belongs to the "always moved," i.e., to the heavenly bodies, which are always in motion — for what is always in motion is compared to what is not forever in motion as agent is compared to patient.

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Lecture 3 Mutual transformation of the elements. Presence above of the heavenly body
Chapter 3
ἀναλαβόντες οὖν τὰς ἐξ ἀρχῆς θέσεις καὶ τοὺς εἰρημένους πρότερον διορισμούς, λέγωμεν περί τε τῆς τοῦ γάλακτος φαντασίας καὶ περὶ κομητῶν καὶ τῶν ἄλλων ὅσα τυγχάνει τούτοις ὄντα συγγενῆ.	11 Let us first recall our original principles and the distinctions already drawn and then explain the 'milky way' and comets and the other phenomena akin to these.
φαμὲν δὴ πῦρ καὶ ἀέρα καὶ ὕδωρ καὶ γῆν γίγνεσθαι ἐξ ἀλλήλων, καὶ ἕκαστον ἐν ἑκάστῳ (339b.) ὑπάρχειν τούτων δυνάμει, ὥσπερ καὶ τῶν ἄλλων οἷς ἕν τι καὶ ταὐτὸν ὑπόκειται, εἰς ὃ δὴ ἀναλύονται ἔσχατον.	12 Fire, air, water, earth, we assert, originate from one another, and each of them exists potentially in each, as all things do that can be resolved into a common and ultimate substrate.
πρῶτον μὲν οὖν ἀπορήσειεν ἄν τις περὶ τὸν καλούμενον ἀέρα, τίνα τε χρὴ λαβεῖν αὐτοῦ τὴν φύσιν ἐν τῷ περιέχοντι κόσμῳ τὴν γῆν, καὶ πῶς ἔχει τῇ τάξει πρὸς τἆλλα τὰ λεγόμενα στοιχεῖα τῶν σωμάτων.	13 The first difficulty is raised by what is called the air. What are we to take its nature to be in the world surrounding the earth? And what is its position relatively to the other physical elements.
ὁ μὲν γὰρ δὴ τῆς γῆς ὄγκος πηλίκος ἄν τις εἴη πρὸς τὰ περιέχοντα μεγέθη, οὐκ ἄδηλον ἤδη γὰρ ὦπται διὰ τῶν ἀστρολογικῶν θεωρημάτων ἡμῖν ὅτι πολὺ καὶ τῶν ἄστρων ἐνίων ἐλάττων ἐστίν.	14 (For there is no question as to the relation of the bulk of the earth to the size of the bodies which exist around it, since astronomical demonstrations have by this time proved to us that it is actually far smaller than some individual stars.
ὕδατος δὲ φύσιν συνεστηκυῖαν καὶ ἀφωρισμένην οὔθ' ὁρῶμεν οὔτ' ἐνδέχεται κεχωρισμένην εἶναι τοῦ περὶ τὴν γῆν ἱδρυμένου σώματος, οἷον τῶν τε φανερῶν, θαλάττης καὶ ποταμῶν, κἂν εἴ τι κατὰ βάθους ἄδηλον ἡμῖν ἐστιν.	15 As for the water, it is not observed to exist collectively and separately, nor can it do so apart from that volume of it which has its seat about the earth: the sea, that is, and rivers, which we can see, and any subterranean water that may be hidden from our observation.)
τὸ δὲ δὴ μεταξὺ τῆς γῆς τε καὶ τῶν ἐσχάτων ἄστρων πότερον ἕν τι νομιστέον εἶναι σῶμα τὴν φύσιν ἢ πλείω, κἂν εἰ πλείω, πόσα, καὶ μέχρι ποῦ διώρισται τοῖς τόποις;	16 The question is really about that which lies between the earth and the nearest stars. Are we to consider it to be one kind of body or more than one? And if more than one, how many are there and what are the bounds of their regions?
ἡμῖν μὲν οὖν εἴρηται πρότερον περὶ τοῦ πρώτου στοιχείου, ποῖόν τι τὴν δύναμίν ἐστιν, καὶ διότι πᾶς ὁ περὶ τὰς ἄνω φορὰς κόσμος ἐκείνου τοῦ σώματος πλήρης ἐστί. καὶ ταύτην τὴν δόξαν οὐ μόνον ἡμεῖς τυγχάνομεν ἔχοντες, φαίνεται δὲ ἀρχαία τις ὑπόληψις αὕτη καὶ τῶν πρότερον ἀνθρώπων ὁ γὰρ λεγόμενος αἰθὴρ παλαιὰν εἴληφε τὴν προσηγορίαν, ἣν Ἀναξαγόρας μὲν τῷ πυρὶ ταὐτὸν ἡγήσασθαί μοι δοκεῖ σημαίνειν τά τε γὰρ ἄνω πλήρη πυρὸς εἶναι, κἀκεῖνος τὴν ἐκεῖ δύναμιν αἰθέρα καλεῖν ἐνόμισεν, τοῦτο μὲν ὀρθῶς νομίσας τὸ γὰρ ἀεὶ σῶμα θέον ἅμα καὶ θεῖόν τι τὴν φύσιν ἐοίκασιν ὑπολαβεῖν, καὶ διώρισαν ὀνομάζειν αἰθέρα τὸ τοιοῦτον ὡς ὂν οὐδενὶ τῶν παρ' ἡμῖν τὸ αὐτό οὐ γὰρ δὴ φήσομεν ἅπαξ οὐδὲ δὶς οὐδ' ὀλιγάκις τὰς αὐτὰς δόξας ἀνακυκλεῖν γιγνομένας ἐν τοῖς ἀνθρώποις, ἀλλ' ἀπειράκις.	17 We have already described and characterized the first element, and explained that the whole world of the upper motions is full of that body. This is an opinion we are not alone in holding: it appears to be an old assumption and one which men have held in the past, for the word ether has long been used to denote that element. Anaxagoras, it is true, seems to me to think that the word means the same as fire. For he thought that the upper regions were full of fire, and that men referred to those regions when they spoke of ether. In the latter point he was right, for men seem to have assumed that a body that was eternally in motion was also divine in nature; and, as such a body was different from any of the terrestrial elements, they determined to call it 'ether'. For the same opinions appear in cycles among men not once nor twice, but infinitely often.
ὅσοι δὲ πῦρ καθαρὸν εἶναί φασι τὸ περιέχον καὶ μὴ μόνον τὰ φερόμενα σώματα, τὸ δὲ μεταξὺ γῆς καὶ τῶν ἄστρων ἀέρα, θεωρήσαντες ἂν τὰ νῦν δεικνύμενα διὰ τῶν μαθημάτων ἱκανῶς ἴσως ἂν ἐπαύσαντο ταύτης τῆς παιδικῆς δόξης λίαν γὰρ ἁπλοῦν τὸ νομίζειν μικρὸν τοῖς μεγέθεσιν εἶναι τῶν φερομένων ἕκαστον, ὅτι φαίνεται θεωροῦσιν ἐντεῦθεν ἡμῖν οὕτως. εἴρηται μὲν οὖν καὶ πρότερον ἐν τοῖς περὶ τὸν ἄνω τόπον θεωρήμασι λέγωμεν δὲ τὸν αὐτὸν λόγον καὶ νῦν. (340a.) εἰ γὰρ τά τε διαστήματα πλήρη πυρὸς καὶ τὰ σώματα συνέστηκεν ἐκ πυρός, πάλαι φροῦδον ἂν ἦν ἕκαστον τῶν ἄλλων στοιχείων.	18 Now there are some who maintain that not only the bodies in motion but that which contains them is pure fire, and the interval between the earth and the stars air: but if they had considered what is now satisfactorily established by mathematics, they might have given up this puerile opinion. For it is altogether childish to suppose that the moving bodies are all of them of a small size, because they so to us, looking at them from the earth. This a matter which we have already discussed in our treatment of the upper region, but we may return to the point now. If the intervals were full of fire and the bodies consisted of fire every one of the other elements would long ago have vanished.
ἀλλὰ μὴν οὐδ' ἀέρος γε μόνου πλήρη	19 However, they cannot simply be said to be full of air either;
πολὺ γὰρ ἂν ὑπερβάλλοι τὴν ἰσότητα τῆς κοινῆς ἀναλογίας πρὸς τὰ σύστοιχα σώματα, κἂν εἰ δύο στοιχείων πλήρης ὁ μεταξὺ γῆς τε καὶ οὐρανοῦ τόπος ἐστίν οὐδὲν γὰρ ὡς εἰπεῖν μόριον ὁ τῆς γῆς ἐστιν ὄγκος, ἐν ᾧ συνείληπται πᾶν καὶ τὸ τοῦ ὕδατος πλῆθος, πρὸς τὸ περιέχον μέγεθος. ὁρῶμεν δ' οὐκ ἐν τοσούτῳ μεγέθει γιγνομένην τὴν ὑπεροχὴν τῶν ὄγκων, ὅταν ἐξ ὕδατος ἀὴρ γένηται διακριθέντος ἢ πῦρ ἐξ ἀέρος ἀνάγκη δὲ τὸν αὐτὸν ἔχειν λόγον ὃν ἔχει τὸ τοσονδὶ καὶ μικρὸν ὕδωρ πρὸς τὸν ἐξ αὐτοῦ γιγνόμενον ἀέρα, καὶ τὸν πάντα πρὸς τὸ πᾶν ὕδωρ.	20 for even if there were two elements to fill the space between the earth and the heavens, the air would far exceed the quantity required to maintain its proper proportion to the other elements. For the bulk of the earth (which includes the whole volume of water) is infinitesimal in comparison with the whole world that surrounds it. Now we find that the excess in volume is not proportionately great where water dissolves into air or air into fire. Whereas the proportion between any given small quantity of water and the air that is generated from it ought to hold good between the total amount of air and the total amount of water.
διαφέρει δ' οὐδὲν οὐδ' εἴ τις φήσει μὲν μὴ γίγνεσθαι ταῦτα ἐξ ἀλλήλων, ἴσα μέντοι τὴν δύναμιν εἶναι κατὰ τοῦτον γὰρ τὸν τρόπον ἀνάγκη τὴν ἰσότητα τῆς δυνάμεως ὑπάρχειν τοῖς μεγέθεσιν αὐτῶν, ὥσπερ κἂν εἰ γιγνόμενα ἐξ ἀλλήλων ὑπῆρχεν.	21 Nor does it make any difference if any one denies that the elements originate from one another, but asserts that they are equal in power. For on this view it is certain amounts of each that are equal in power, just as would be the case if they actually originated from one another.
ὅτι μὲν οὖν οὔτ' ἀὴρ οὔτε πῦρ συμπεπλήρωκε μόνον τὸν μεταξὺ τόπον, φανερόν ἐστι	22 So it is clear that neither air nor fire alone fills the intermediate space.

Ostenso quae sunt principia activa et quae sunt principia materialia passionum de quibus intendit tractare, incipit nunc determinare de eis. Et dividitur in partes duas:	15. Having identified which are the active principles and which the material principles of the passions which he intends to treat, he now begins to determine concerning them. And this is divided into two parts:
in prima determinat de particularibus transmutationibus elementorum quibus secundum se transmutantur; in secunda determinat de transmutationibus eorum secundum quod veniunt in compositionem mixti, in quarto libro, ibi: quoniam autem quatuor et cetera.	In the first he determines concerning the particular transmutations of the elements, whereby they are transmuted according to themselves, at 15; Secondly, he determines about their transmutations accordingly as they enter into composition to form a mixture, in Book IV.
Prima autem pars dividitur in duas:	The first part is divided into two parts:
in prima enim determinat de transmutationibus seu passionibus elementorum quae in alto accidunt; in secunda de his quae accidunt in infimo, et hoc in secundo libro, ibi: de mari autem et cetera.	In the first he determines concerning the transmutations or passions of the elements which occur on high; In the second, about those which occur below, and this in Book II.
Prima autem pars dividitur in tres:	The first part is divided into three parts:
in prima dicit de quo est intentio; in secunda praemittit quaedam quae sunt necessaria ad subsequentium determinationem, ibi: dicimus itaque ignem et aerem etc., in tertia incipit determinare de principali proposito, ibi: his autem determinatis et cetera.	In the first he declares what his intention is; In the second he states certain preliminaries necessary for determining what is to follow, at 16; In the third he begins to determine concerning his main proposition (L.6).
Dicit ergo primo quod dicendum est de phantasia lactis, idest de apparitione lactei circuli, et de cometis, et de aliis omnibus huiusmodi quae sunt his syngenea, idest congenerabilia; ita tamen quod resumamus positiones a nobis positas in prioribus libris, et determinationes in eis prius determinatas, ut eis utamur ad propositum manifestandum, cum opus fuerit.	He says therefore first [11] that we must speak of the "image of the milk," i.e., of the appearance of the milky circle, and of comets and of all other like things which are "syngeneous," i.e., generable along with them; but in doing so we shall [first] recall the positions laid down by us in the earlier books and the determinations already determined therein, so that we may, when necessary, use them to manifest the proposition.
Deinde cum dicit: dicimus itaque ignem et aerem etc., praemittit quaedam quae sunt necessaria ad subsequentia. Et circa hoc duo facit:	16. Then [12] he sets forth certain things needed for what is to follow. About this he does two things:
primo praemittit aliquid quod pertinet ad transmutationem elementorum adinvicem; secundo dicit de ordinatione eorum in mundo, et specialiter de aere, ibi: primum quidem igitur dubitabit et cetera.	First, he premises something pertaining to the mutual transmutation of the elements, at 16; Secondly, he speaks of the arrangement of the elements in the world, with special emphasis on air, at 17.
Dicit ergo primo quod ignis et aer et aqua et terra fiunt ex invicem, quamvis Empedocles contrarium senserit: et hoc resumit ut probatum in II de Generat. Et huius rationem assignat, quia unumquodque elementorum est in alio in potentia; et quae sic se habent, adinvicem generari possunt. Ulterius huius rationem assignat, quia communicant in una materia prima, quae eis subiicitur, et in quam sicut in ultimum resolvuntur: omnia enim quorum materia est una communis, sic se habent quod unum eorum est potentia in alio; sicut cultellus est potentia in clavi, et clavis in cultello, quia utriusque materia communis est ferrum.	He says therefore first [12] that fire and air and water and earth are produced from one another (even though Empedocles thought the contrary). And he restates this as proved in On Generation II. The reason for this which he assigns is that each element exists potentially in another, and that things so related can be generated one from the other. He assigns a further reason, which is that they all have the same common first matter which underlies each of them and into which, as into an ultimate, they are all resolved: for all things whose matter is one and common to all are so related that any one is potentially in any other — as, for example, a knife is potentially in a nail, and a nail potentially in a knife, because they have a common matter, iron.
Deinde cum dicit: primum quidem igitur dubitabit etc., inquirit de ordine elementorum, et praecipue aeris. Et circa hoc tria facit.	17. Then [13] he inquires into the order of the elements and into the case of air in particular. About this he does three things:
Primo movet quaestionem: et dicit quod primo dubitatur circa corpus quod vocatur aer, quam naturam habeat in mundo qui ambit terram, utrum scilicet totum sit aer; et si non, quomodo ordinetur ad alia elementa.	First he raises the question and says that our first problem is about the body called "air," as to what nature it has in the world surrounding the earth: i.e., is the whole air, and, if not, how it is related to the other elements?
Secundo ibi: moles quidem enim etc., proponit quaedam circa ordinem elementorum manifesta. Quorum primum est de terra: scilicet quod non est immanifestum quanta sit moles terrae, per comparationem ad magnitudines ambientes, scilicet caelestium corporum et aliorum elementorum. Iam enim apparuit per considerationes astrologicas, quod terra est multo minor quibusdam astris, et quod in comparatione ad ultimam sphaeram obtinet vicem puncti.	Secondly [14], he proposes certain evident facts about the order of the elements. The first fact concerns the earth, and it is that we are not entirely ignorant of the size of the earth in comparison to the surrounding magnitudes, namely, those of the heavenly bodies and of the other elements. For it is already plain from the considerations of astronomers that the earth is much smaller than certain stars, and that it is but the size of a point in comparison to the outermost sphere.
Secundum proponit de aqua, ibi: aquae autem naturam et cetera. Et dicit quod non videmus aquam per se constantem, et separatam a corpore locato circa terram, scilicet a mari et fluminibus, quae sunt manifesta nobis, et a congregationibus aquarum, si quae sunt in profundo terrae immanifestae nobis, ut quidam posuerunt. Nec etiam contingit aquam sic congregatam esse: eo quod humidum aqueum non terminatur nisi termino alieno.	The second fact he proposes is about water [15] and he says that we do not observe water to exist by itself and isolated from the body located about the earth, namely, from the sea and rivers, which we see, and from the bodies of water which some have asserted to exist hidden from us in the bowels of the earth. For it does not occur to water to be gathered together in this way — since the moistness which is water is contained by some alien terminus.
Iterum ibi: intermedium autem terrae etc., hic prosequitur quaestionem suam iam motam, qua quaerit quid est inter praedicta medium.	18. He further [16] pursues the question he raised earlier, namely, as to what is the middle between the aforesaid [i.e., the earth and the farthest stars].
Et circa hoc duo facit.	About this he does two things:
Primo enim ostendit quod non totum spatium quod est a supremis stellis usque ad terram, est plenum uno aliquo corpore, scilicet igne vel aere, aut utroque; sed supra hoc est aliquod corpus praeter ista. Secundo ostendit quomodo ad illud supremum corpus ordinentur alia corpora secundum positionem, ibi: reliquum est autem et cetera.	First, he shows [16] that it is not the case that the entire space from the highest stars to the earth is filled with some one body such as fire or air or both, but that above there is an additional body besides these; Secondly, he shows how the other bodies are related to that highest body with respect to position (L. 4).
Circa primum sic procedit. Primo dicit quod dubium est utrum inter terram et inter astra ultima, quae dicuntur non errantia sed fixa, sit putandum esse unum corpus, secundum proprietatem naturae, vel plura: et si plura, quot sunt, et ubi terminentur secundum locum.	Regarding the first he proceeds thus. First [16] he says that there is a problem whether between earth and the farthest stars, which are called "non-wandering" and "fixed," we should posit, according to what is proper to nature, one body or more than one; and if more than one, how many, and where are the boundaries of their regions?
Secundo ibi: nobis quidem igitur etc., resumit quoddam in libro de caelo determinatum: quod est, quale est, secundum virtutem, primum elementum, scilicet caeleste corpus; et quod totus ille mundus qui est circa superiores lationes, idest qui movetur motu circulari, est plenus illo corpore; omnia enim corpora caelestia ad naturam illius primi elementi pertinent. Et quia philosophi ponebant contrarium, ideo, ne sua opinio nova videretur, subiungit quod hanc opinionem non solum ipse habuit, sed fuit etiam antiqua opinio priorum hominum. Illud enim corpus quod dicitur aether, quod nos caelum dicimus, antiquam habet appellationem.	19. Secondly [17], he repeats something already determined in On the Heavens: this is the condition, as far as its power is concerned, of the first element, namely, the celestial body; and that that entire world which is "about the upper motions," i.e., which is moved with a circular motion, is filled with that body — for all the heavenly bodies pertain to the nature of that first element. And since the philosophers supposed the contrary, he therefore, lest his opinion appear novel, adds that not only did he have this opinion, but it was also an ancient opinion of earlier men. For the body which is called "aether," and which we call the "heaven," has an ancient name.
Sed Anaxagoras videtur putasse quod significaret idem quod ignis: accepit enim quod aether dicitur non propter semper currere, idest continue moveri, sed ab aethein, quod est ardere; quia superiora corpora credidit esse plena igne. Et quamvis in hoc male diceret, ut ibi probatum est, tamen hoc recte putavit, quod nomen aetheris conveniret alicui potentiae corporali quae est praeter ista corpora. Omnes enim antiqui visi sunt opinari, et determinaverunt illud corpus nominari aethera, quod semper currit, idest movetur, et quod est quoddam divinum, idest perpetuum, secundum suam naturam; tanquam illud corpus nulli corporum quae sunt apud nos, sit idem. Nec est mirum si hanc opinionem, quam nos de novo videbamur assumpsisse, etiam antiqui habuerunt: quia nos dicimus quod eaedem opiniones sunt reiteratae in hominibus, postquam desierunt propter negligentiam studii, non tantum bis vel ter, sed infinities. Hoc autem dicit secundum suam opinionem, qua putavit mundum et generationem hominum fuisse ab aeterno, ut apparet in prioribus libris: hoc enim supposito, manifestum fit quasdam opiniones et artes a quibusdam certis temporibus incoepisse; et oportet dicere quod multoties, vel magis infinities, sunt destructae, propter bella vel alias corruptiones, et iterum reinventae.	But Anaxagoras seems to have supposed that it means the same as "fire" - for he took the word "aether" not to mean "always running," i.e., to be in continuous motion, but he derives it from aethein, which is "to burn," because he believed the superior bodies to be filled with fire. And although in this he spoke ill, nevertheless he was right in supposing the name "aether" to befit a corporeal potency over and above those bodies. For all the ancients are seen to have believed, and decided, that the name "aether" should be given to the body which always "runs," i.e., is always in motion, and which is a certain "divine," i.e., perpetual, something according to its nature. This they did as if that body were like no body that exists around us. Nor should it seem strange if this opinion, which we appeared to have adopted for the first time, was already held by the ancients. For we hold that the same opinions re-appear among men after dying out through neglect of study, not twice or thrice only, but an infinitude of times. Now he says this in keeping with his opinion that the world and human generation have been going on from eternity, as indicated in previous books. This being supposed, it is also plain that certain opinions and arts have begun from certain definite times; and thus it is necessary to say that these were in turn frequently, nay, an infinitude of times, destroyed by wars or other corrupting factors and again rediscovered.
Tertio ibi: quicumque autem ignem etc., ostendit quod non est unum horum corporum inferiorum, corpus quod circulariter movetur. Et circa hoc tria facit:	20. Thirdly [18], he shows that the circularly moved body is not any of the lower bodies. About this he does three things:
primo ostendit hoc quantum ad ignem; secundo quantum ad aerem, ibi: at vero neque aere etc.; tertio quantum ad utrumque, ibi: et etiam si duobus et cetera.	First, he shows this with respect to fire; Secondly, with respect to air, at 21; Thirdly, with respect to both, at 22.
Circa primum sciendum est quod aliqui putaverunt solum corpora caelestia delata, idest solem, lunam et stellas, esse naturae igneae; quod vero est inter eas, est naturae aereae: quidam vero posuerunt totum esse naturae igneae, sicut Anaxagoras dixit.	With respect to the first [l8] it should be kept in mind that some have thought only the "carried" [moved] heavenly bodies, i.e., the sun, moon and stars, to have a fiery nature, and whatever exists between them to be of the nature of air; some on the other hand supposed the entire system to be of the nature of fire, as Anaxagoras said.
Dicit ergo quod quicumque posuerunt non solum corpora delata ignem purum, sed totum ambiens, scilicet omnes sphaeras; et id quod est intermedium terrae et astrorum est aer, scilicet a terra usque ad orbem lunae, et quod est desuper, totum est ignis; qui, inquam, sic dicunt, si considerarent ea quae nunc sunt sufficienter ostensa per mathematicam de magnitudinibus corporum, forte desisterent ab hac puerili opinione. Valde enim simplicis hominis est et ineruditi putare stellas esse parvas magnitudinibus, quia videntur parvae nobis tam a remotis aspicientibus.	He says therefore that those who posited not only the moving bodies to be pure fire, but also the whole that surrounds them (i.e., all the spheres), and that which intervenes between earth and the stars to be air, i.e., from the earth to the moon's orb, and that whatever is above is all of it fire — whoever, I say, claim this, would, were they to consider the facts which have now been sufficiently proved by the mathematicians concerning the sizes of bodies, probably give up this childish opinion. Only a simple and unschooled person would believe that the stars are small in size just because they appear small to us looking at them from afar.
Dictum est autem de his in superioribus theorematibus, scilicet in II de caelo: sed etiam nunc eadem ratione dicemus ad destructionem praedictae positionis. Cum enim corpora astrorum et sphaerarum quasi improportionaliter excedant quantitatem terrae et eorum quae sunt circa terram, si non solum corpora stellarum constarent ex igne, sed etiam distantiae quae sunt inter eas essent plenae igne, iam olim annihilatum esset unumquodque aliorum elementorum, propter excessum ignis super ea.	This matter has been already discussed in the previous reasonings, i.e., in On the Heavens II; but we shall once more destroy the aforesaid position with the same argument. For, since the bodies of the stars and spheres are immeasurably greater than the size of the earth and of the things near the earth, then, if not only the bodies of the stars were of fire, but all the area between them were full of fire, every one of the elements would have long since been annihilated by virtue of the preponderance of fire over it.
Deinde cum dicit: at vero neque aere etc., ostendit idem quantum ad aerem, dicens quod non est possibile quod istae distantiae sint plenae aere. Manifestum est enim quod adhuc quantitas aeris multum excederet aequalitatem analogiae, idest proportionis, quae debet esse communis inter elementa, ad hoc quod elementa conserventur.	[Then... he shows the same with regard to air, saying that it is not possible for those distances to be full of air. For it is clear that the quantity of air would still exceed the equality of analogy - that is proportion - which should be common among the elements, so that the elements may be preserved.]
Deinde cum dicit: et etiam si duobus etc., ostendit idem quantum ad utrumque. Et circa hoc duo facit:	21. Then [19] he shows the same thing with respect to both. About this he does two things:
primo ponit rationem; secundo excludit quandam cavillationem, ibi: differt autem nihil et cetera.	First, he gives the reason, at 22; Secondly, he excludes a certain cavilling objection, at 23.
Dicit ergo primo quod proportio debita elementorum non servatur, si totus locus qui est medius inter terram et supremum caelum, est plenus duobus elementis, scilicet igne et aere. Quia moles terrae, in qua continetur etiam omnis aquae multitudo, quasi nulla pars est, habens proportionem ad totam magnitudinem ambientium corporum, cum ad solam ultimam sphaeram obtineat vicem puncti, secundum astronomos. Videmus autem quod, cum ex aqua per disgregationem sive rarefactionem fit aer, aut ex aere ignis, non est tam immensus excessus quantitatis. Oportet autem ad hoc quod conservetur debita proportio in elementis, quod eandem rationem, idest proportionem, habeat haec parva aqua ad aerem factum ex ipsa, et tota aqua ad totum aerem; ut videlicet quantum excedit quantitas aeris quantitatem aquae ex qua fit, tantum excedat in mundo quantitas totius aeris quantitatem totius aquae.	He says therefore first [20] that the due proportion among the elements is not kept, if the entire space between the earth and the outermost heaven is full of two elements, namely, fire and air. For the bulk of the earth, in which the whole quantity of water is also contained, is as no part at all compared to the total size of the bodies surrounding it, since, according to astronomers, even if compared only to the outermost sphere, it is as a mere point. But we see that when, as a result of separation or rarefaction, air comes to be from water, or fire from air, there is not such an immense excess in size. Now it is necessary, if the due proportion prevailing among the elements is to be preserved, that this small quantity of water maintain the same "reason," i.e., proportion, to the air made from it, as is maintained between the whole of water and the whole of air. In other words, the extent to which the quantity of air exceeds the quantity of water from which it is made must be proportional to the extent that all the air in the world exceeds all the water in the world.
Deinde cum dicit: differt autem nihil etc., excludit quandam cavillationem: dicens quod nihil differt ad propositum si quis dicat, secundum opinionem Empedoclis, quod elementa non generantur ex invicem. Oportet enim, secundum eius opinionem, elementa esse aequalia proportione virtutis. Unde sic oportet quod conservetur aequalitas proportione virtutis in magnitudinibus elementorum, si non generantur ex invicem, sicut si generarentur.	22. Then [21] he refutes a certain cavilling objection and says that it is nothing against our position if someone should maintain, according to the opinion of Empedocles, that the elements are not generated from one another. For it is necessary, according to his opinion, that the elements be proportionally equal in power. Consequently, proportionate equality of power must be kept in the sizes of the elements if they are not generated one from the other, just as if they are.
Deinde recolligit quod dictum est, concludens ex dictis manifestum esse quod neque aer tantum replet medium locum qui est inter terram et supremas stellas, neque ignis: sed praeter haec duo elementa, oportet super ipsa esse corpus caeleste, quod nullum inferiorum est elementorum.	23. Then he summarizes [22] what has been said, and concludes that it is plain from the foregoing that neither does air fill the intermediate place between the earth and the highest stars, nor does fire; but, in addition to these two elements, there must be above them a heavenly body which is none of the lower elements.

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Lecture 4 Three questions. The first, on the order of the elements, is solved
Chapter 3 cont.
λοιπὸν δὲ διαπορήσαντας εἰπεῖν πῶς τέτακται τὰ δύο πρὸς τὴν τοῦ πρώτου σώματος θέσιν, λέγω δὲ ἀέρα τε καὶ πῦρ,	23 It remains to explain, after a preliminary discussion of difficulties, the relation of the two elements air and fire to the position of the first element,
καὶ διὰ τίν' αἰτίαν ἡ θερμότης ἀπὸ τῶν ἄνωθεν ἄστρων γίγνεται τοῖς περὶ τὴν γῆν τόποις.	24 and the reason why the stars in the upper region impart heat to the earth and its neighbourhood.
περὶ ἀέρος οὖν εἰπόντες πρῶτον, ὥσπερ ὑπεθέμεθα, λέγωμεν οὕτω καὶ περὶ τούτων πάλιν. εἰ δὴ γίγνεται ὕδωρ ἐξ ἀέρος καὶ ἀὴρ ἐξ ὕδατος, διὰ τίνα ποτ' αἰτίαν οὐ συνίσταται νέφη κατὰ τὸν ἄνω τόπον; προσῆκε γὰρ μᾶλλον ὅσῳ πορρώτερον ὁ τόπος τῆς γῆς καὶ ψυχρότερος, διὰ τὸ μήθ' οὕτω πλησίον εἶναι τῶν ἄστρων θερμῶν ὄντων μήτε τῶν ἀπὸ τῆς γῆς ἀνακλωμένων ἀκτίνων, αἳ κωλύουσι πλησίον τῆς γῆς συνίστασθαι, διακρίνουσαι τῇ θερμότητι τὰς συστάσεις γίγνονται γὰρ αἱ τῶν νεφῶν ἀθροίσεις, οὗ λήγουσιν ἤδη διὰ τὸ σχίζεσθαι εἰς ἀχανὲς αἱ ἀκτῖνες.ἢ οὖν οὐκ ἐξ ἅπαντος τοῦ ἀέρος πέφυκεν ὕδωρ γίγνεσθαι, ἢ εἰ ὁμοίως ἐξ ἅπαντος, ὁ περὶ τὴν γῆν οὐ μόνον ἀήρ ἐστιν ἀλλ' οἷον ἀτμίς, διὸ πάλιν συνίσταται εἰς ὕδωρ. ἀλλὰ μὴν εἰ τοσοῦτος ὢν ὁ ἀὴρ ἅπας ἀτμίς ἐστι, δόξειεν ἂν πολὺ ὑπερβάλλειν ἡ τοῦ ἀέρος φύσις καὶ ἡ τοῦ ὕδατος, εἴπερ τά τε διαστήματα τῶν ἄνω πλήρη ἐστὶ (340b.) σώματός τινος, καὶ πυρὸς μὲν ἀδύνατον διὰ τὸ κατεξηράνθαι ἂν τἆλλα πάντα, λείπεται δ' ἀέρος καὶ τοῦ περὶ τὴν γῆν πᾶσαν ὕδατος ἡ γὰρ ἀτμὶς ὕδατος διάκρισίς ἐστιν. περὶ μὲν οὖν τούτων ἠπορήσθω τοῦτον τὸν τρόπον	25 Let us first treat of the air, as we proposed, and then go on to these questions. Since water is generated from air, and air from water, why are clouds not formed in the upper air? They ought to form there the more, the further from the earth and the colder that region is. For it is neither appreciably near to the heat of the stars, nor to the rays relected from the earth. It is these that dissolve any formation by their heat and so prevent clouds from forming near the earth. For clouds gather at the point where the reflected rays disperse in the infinity of space and are lost. To explain this we must suppose either that it is not all air which water is generated, or, if it is produced from all air alike, that what immediately surrounds the earth is not mere air, but a sort of vapour, and that its vaporous nature is the reason why it condenses back to water again. But if the whole of that vast region is vapour, the amount of air and of water will be disproportionately great. For the spaces left by the heavenly bodies must be filled by some element. This cannot be fire, for then all the rest would have been dried up. Consequently, what fills it must be air and the water that surrounds the whole earth-vapour being water dissolved. After this exposition of the difficulties involved,
ἡμεῖς δὲ λέγωμεν ἅμα πρός τε τὰ λεχθησόμενα διορίζοντες καὶ πρὸς τὰ νῦν εἰρημένα. τὸ μὲν γὰρ ἄνω καὶ μέχρι σελήνης ἕτερον εἶναι σῶμά φαμεν πυρός τε καὶ ἀέρος, οὐ μὴν ἀλλ' ἐν αὐτῷ γε τὸ μὲν καθαρώτερον εἶναι τὸ δ' ἧττον εἰλικρινές, καὶ διαφορὰς ἔχειν, καὶ μάλιστα ᾗ καταλήγει πρὸς τὸν ἀέρα καὶ πρὸς τὸν περὶ τὴν γῆν κόσμον.	26 let us go on to lay down the truth, with a view at once to what follows and to what has already been said. The upper region as far as the moon we affirm to consist of a body distinct both from fire and from air, but varying degree of purity and in kind, especially towards its limit on the side of the air, and of the world surrounding the earth.
φερομένου δὲ τοῦ πρώτου στοιχείου κύκλῳ καὶ τῶν ἐν αὐτῷ σωμάτων, τὸ προσεχὲς ἀεὶ τοῦ κάτω κόσμου καὶ σώματος τῇ κινήσει διακρινόμενον ἐκπυροῦται καὶ ποιεῖ τὴν θερμότητα. δεῖ δὲ νοεῖν οὕτως καὶ ἐντεῦθεν ἀρξαμένους. τὸ γὰρ ὑπὸ τὴν ἄνω περιφορὰν σῶμα οἷον ὕλη τις οὖσα καὶ δυνάμει θερμὴ καὶ ψυχρὰ καὶ ξηρὰ καὶ ὑγρά, καὶ ὅσα ἄλλα τούτοις ἀκολουθεῖ πάθη, γίγνεται τοιαύτη καὶ ἔστιν ὑπὸ κινήσεως καὶ ἀκινησίας, ἧς τὴν αἰτίαν καὶ τὴν ἀρχὴν εἰρήκαμεν πρότερον.	27 Now the circular motion of the first element and of the bodies it contains dissolves, and inflames by its motion, whatever part of the lower world is nearest to it, and so generates heat. From another point of view we may look at the motion as follows. The body that lies below the circular motion of the heavens is, in a sort, matter, and is potentially hot, cold, dry, moist, and possessed of whatever other qualities are derived from these. But it actually acquires or retains one of these in virtue of motion or rest, the cause and principle of which has already been explained.
ἐπὶ μὲν οὖν τοῦ μέσου καὶ περὶ τὸ μέσον τὸ βαρύτατόν ἐστιν καὶ ψυχρότατον ἀποκεκριμένον, γῆ καὶ ὕδωρ περὶ δὲ ταῦτα καὶ ἐχόμενα τούτων, ἀήρ τε καὶ ὃ διὰ συνήθειαν καλοῦμεν πῦρ, οὐκ ἔστι δὲ πῦρ ὑπερβολὴ γὰρ θερμοῦ καὶ οἷον ζέσις ἐστὶ τὸ πῦρ. ἀλλὰ δεῖ νοῆσαι τοῦ λεγομένου ὑφ' ἡμῶν ἀέρος τὸ μὲν περὶ τὴν γῆν οἷον ὑγρὸν καὶ θερμὸν εἶναι διὰ τὸ ἀτμίζειν τε καὶ ἀναθυμίασιν ἔχειν γῆς, τὸ δὲ ὑπὲρ τοῦτο θερμὸν ἤδη καὶ ξηρόν. ἔστιν γὰρ ἀτμίδος μὲν φύσις ὑγρὸν καὶ θερμόν, ἀναθυμιάσεως δὲ θερμὸν καὶ ξηρόν καὶ ἔστιν ἀτμὶς μὲν δυνάμει οἷον ὕδωρ, ἀναθυμίασις δὲ δυνάμει οἷον πῦρ.	28 So at the centre and round it we get earth and water, the heaviest and coldest elements, by themselves; round them and contiguous with them, air and what we commonly call fire. It is not really fire, for fire is an excess of heat and a sort of ebullition; but in reality, of what we call air, the part surrounding the earth is moist and warm, because it contains both vapour and a dry exhalation from the earth. But the next part, above that, is warm and dry. For vapour is naturally moist and cold, but the exhalation warm and dry; and vapour is potentially like water, the exhalation potentially like fire.

Postquam philosophus ostendit ignem et aerem non esse corpus caeleste, quod vocatur primum elementum sive primum corpus, nunc intendit ostendere quomodo ignis et aer se habeant ad illud primum corpus. Et circa hoc duo facit:	24. After showing that neither fire nor air is the heavenly body called "first element" or "first body," he now intends to show how fire and air are related to that first body. Concerning this he does two things:
primo movet hanc quaestionem, et duas alias necessarias ad propositum; secundo solvit eas, ibi: nos autem dicamus et cetera.	First, he raises this question, and two others necessary for his proposition, at 24; Secondly, he answers them, at 26.
Prima dividitur in tres, secundum tres quaestiones quas movet: secunda incipit ibi: et propter quam causam etc.; tertia ibi: de aere igitur et cetera.	The first is divided into three parts, according to the three questions raised: The second begins at 25; The third at 26.
Dicit ergo primo quod post praedicta relinquitur perscrutari de ordine aeris et ignis ad primum corpus, scilicet caeleste, ex quo ostensum est ipsum esse aliud praeter ista.	He says therefore first [23] that after the above considerations there remains to be examined the relation of air and of fire to the first body, namely, the heavenly body, since it has been shown that it is something other than they.
Deinde cum dicit: et propter quam causam etc., movet secundam quaestionem: scilicet, propter quam causam a superioribus stellis causetur caliditas in his locis quae sunt circa terram. Et haec etiam quaestio habet ortum ex praemissis. Videtur enim secundum naturam esse quod simile generet sibi simile: si igitur corpus caeleste non est calidum, quia non est ignis neque aer, ut supra habitum est, remanet in dubio quomodo a corpore caelesti possit causari calor in istis inferioribus.	25. Then [24] he places the second question, namely, as to what cause is due the fact that from the upper stars heat is produced in the regions surrounding earth. This question, too, takes its rise from the foregoing considerations. For it seems to be according to nature that like should generate like: if, therefore, the heavenly body is not hot — for it is neither fire nor air, as was shown above — then there remains the problem of how heat can be caused by the heavenly body in these lower bodies.
Deinde cum dicit: de aere igitur etc., movet tertiam dubitationem, quae etiam ex praemissis ortum habet. Dixerat enim prius quod oportebat considerare quomodo sit accipienda natura aeris in universo: et hoc ideo, quia multa eorum de quibus determinaturus est, generationem habent in aere. Dicit ergo quod, sicut supra supposuimus, oportet primo aliquid dicere de aere: et sic erit dicendum de aliis duobus quaestionibus motis.	26. Then [25] he raises the third problem which also arises from the foregoing. For he had said previously that we must inquire how the nature of air in the universe is to be taken, and this for the reason that many of the things concerning which he is about to determine are generated in the air. He says therefore that, as we laid down above, we must first speak of air; then we shall have to discuss the other two questions proposed.
Unde statim incipit movere dubitationem ad naturam aeris pertinentem. Ostensum est enim in libro de Generat. quod aqua fit ex aere, et e converso. Cum autem ex condensationibus nubium generatur pluvia, hoc est aerem converti in aquam. Quaerit ergo, si aqua fit ex aere et aer ex aqua, quare in superiori parte aeris non inspissentur nubes ad generationem aquae.	Hence he immediately begins to raise the difficulty on the nature of air. For it has been shown in On Generation II that water is produced from air and conversely. Thus, since the rains are generated from the condensings of the clouds, this is air being converted into water. He asks, therefore, if water comes to be from air, and air from water, why is it that, in the upper region of air, clouds are not condensed [thickened] to generate water?
Et inducit rationem ad ostendendum quod hoc fieri deberet. Manifestum est enim quod condensatio nubium fit ex frigiditate: nam sicut calidi est rarefacere, ita frigidi inspissare. Locus autem aeris qui est remotior a terra, videtur esse frigidior: quia videntur ibi cessare duae causae calefactionis. Quarum una est propinquitas ad astra, ex quibus causatur calor: et hoc tangit cum dicit quod neque ille locus aeris, superior scilicet, est sic prope astra existentia calida, scilicet secundum effectum, ut caliditas astrorum possit impedire inspissationem nubium. Alia causa calefactionis est reverberatio radiorum solis a terra: et hoc tangit cum dicit: neque iterum ille locus superioris aeris est prope radios refractos, idest reverberatos, a terra, qui prohibent congregari nubes prope terram, per hoc quod sua caliditate disgregant consistentias vaporum. Et quod haec secunda causa non impediat congregationem, manifestat per signum. Manifestum est enim quod congregationes nubium fiunt ibi, ubi radii repercussi a terra iam desinunt habere virtutem calefaciendi, propter hoc quod in immensum sparguntur, et sic multum distant a radiis cadentibus; unde non multiplicatur causa caloris.	And he gives a reason to show that such a thing should happen. For it is plain that condensation of clouds is due to coldness, for just as heat causes things to rarify, so cold causes things to condense. Now it seems that a place should be colder the farther it is from earth, because in such a place the two causes of heating are lacking. One of these causes is proximity to the stars that cause heat; and this is referred to when he says that the upper region of air is not close enough to the stars which are hot, namely, as to effect, to allow the heat of the stars to prevent the thickening of clouds. The other cause of heat is solar rays bouncing back from the earth; this cause he refers to when he says that neither is that region of upper air near the rays "refracted," i.e., reverberated, from the earth, which rays prevent clouds from gathering close to the earth, inasmuch as their heat breaks down the consistency of the vapors. That this second cause does not prevent congregation he shows through a sign. For it is plain that the comings together of clouds occur where the rays reflected from the earth have already lost their power to heat through being immeasurably dispersed and are thus far distant from the rays that strike the earth; hence the cause of heat is not multiplied.
Ad huius autem intelligentiam, sciendum est quod radii procedentes a sole ad terram sunt causa caliditatis. Cum autem radius in terram cadens repercutitur, fit iterum alius radius a terra quasi resursum tendens. Quanto ergo hi duo radii fuerint magis sibi invicem propinqui, tanto plus de calore causatur: quia virtus utriusque radii, scilicet cadentis et reflexi, pertingit ad eandem partem aeris. Et inde est quod ubi radius solis cadens super terram facit angulum rectum, ibi est maximus calor, quia reflexio fit in eandem partem: quanto vero radius cadens in aliquo loco fecerit angulum maiorem recto, tanto est minus de calore; quia, cum repercussio fiat secundum pares angulos, radius repercussus, propter amplitudinem anguli, multum distat a radio primo cadente. Manifestum est autem quod quanto duae lineae continentes angulum magis procedunt, tanto magis distant abinvicem. Unde quanto magis receditur a terra, ubi fit reverberatio, tanto praedicti duo radii magis distant abinvicem, et est minor calor. Et ideo propter immensam separationem praedictorum radiorum abinvicem in loco superiori, desinit calor, et condensantur ibi nubes propter frigus. Et hoc est quod dicit: nubium congregationes fiunt ubi desinunt iam radii propter spargi in immensum. Sic igitur utraque causa quae posset impedire congregationem nubium in superiori parte aeris, cessat, ut dictum est. Et cum ibi non condensentur nubes, oportet dicere quod aqua non sit nata fieri ex omni aere: aut si similiter se habet omnis aer ad hoc quod generetur ex eo aqua, oportet quod iste aer qui est circa terram, non solum sit aer, sed sicut vapor, et ex hac causa congregetur ad generationem aquae; superior autem, qui est purus aer, non posset condensari in aquam. Sed hoc non potest esse: quia si totus iste aer qui est circa terram, cum sit tam magnus, vapor est, videtur sequi quod natura aeris et aquae multum excedat alia elementa. Quia superiores distantiae, quae scilicet sunt inter stellas, sunt plenae aliquo corpore, cum nihil sit vacuum, ut in IV Physic. probatum est: impossibile est autem quod sint plenae igne, quia sic omnia alia exsiccarentur, ut supra probatum est: relinquitur ergo quod sint plenae aere, et illud quod est circa terram sit plenum aqua. Sed hic aer est vapor: quia vapor est quaedam disgregatio aquae, idest aqua rarefacta.	This last statement becomes plain if we keep in mind the fact that the rays coming from the sun to the earth are what cause heat. When a ray which comes from the sun to earth is reflected, there is now produced another ray as though moving upwards from the earth. The closer these two rays are to each other, the greater the heat produced, because the powers of both rays, i.e., that of the incident ray and that of the reflected ray, act on the same part of the air. Consequently, where a ray of the sun strikes the earth at a right angle, there a maximum of heat is produced, because the ray is reflected into the same direction; when a ray falling on some place strikes at an angle less than a right angle, the heat is by that much less, since, as repercussion takes place according to similar angles, a reflected ray, because of the wideness of the angle, is greatly distant from the ray which first falls. It is plain that the farther two lines containing an angle proceed, the greater becomes the distance between them. Hence, the farther one moves from the earth, where reflexion takes place, the farther the aforesaid two rays grow distant from each other, and there is less heat. Therefore, due to the immense separation of the aforesaid rays from one another in the upper region, the heat ceases, and clouds are formed there on account of the cold. And this what he says: "Gatherings of clouds are produced where the rays now cease because of immeasurable scatterings." Consequently, both causes that could prevent forming of clouds are absent in the upper region of air, as has been said. But since, notwithstanding this, clouds do not form there, it is necessary to spy either that water cannot be formed from just any air, or, if all air is alike so far as being convertible into water is concerned, this air near the earth must not only be air, but as a vapor, and for this reason be gathered to generate water, while the upper air, which is pure air, cannot be condensed into water. But this cannot be: for if the totality of air near the earth, since it is such a great amount, is vapor, then it is seen to follow that the nature of air and of water would far exceed the other elements. Because the higher distances, between the stars, are filled with some body (for there is no such thing as a void, as was proved in Physics IV, and they cannot be filled with fire, for this would result in everything's drying up, as was proved above, consequently they must be filled with air, while the region near the earth is filled with water. But this air is vaporous, for vapor is a certain "disjoining of water," i.e., rarefied water.
Et sic positis tribus quaestionibus, quasi colligens subdit quod de praedictis dubitatum sit hoc modo.	Then, having presented the three questions, he adds, as though summarizing, that the problems concerning the aforesaid have been raised in this manner.
Deinde cum dicit: nos autem dicamus etc., solvit propositas quaestiones:	27. Then at [26] he solves the questions proposed:
et primo eam quae est de ordinatione elementorum; secundo eam quae est de generatione nubium, ibi: eius quidem igitur etc.; tertio eam quae est de caliditate a stellis in inferioribus causata, ibi: de facta autem caliditate et cetera.	First, the question about the order of the elements; Secondly, the one about generation of clouds (L. 5); Thirdly, the one about heat produced in lower bodies by the stars (L. 5).
Circa primum tria facit. Primo resumit quod dictum est de natura primi corporis: dicens quod, ad intellectum et eorum quae nunc quaesita sunt, et eorum quae postmodum sunt dicenda, oportet determinando dicere quod supremum corpus usque ad lunam est alterum ab igne et aere, sicut iam ostensum est; et quod in ipso supremo corpore est aliquid purius, et aliquid minus purum vel sincerum: non quod ibi sit aliqua compositio vel mixtio extraneae naturae; sed magis purum dicitur quod est magis nobile, magis virtuosum, magis formale. Unde et habet differentias in virtute et nobilitate: et maxime ista differentia manifesta est ex illa parte qua desinit ad aerem et ad mundum inferiorem qui est circa terram; in luna enim apparet defectus luminis, et quando est plena, apparent in ea quaedam umbrositates.	Regarding the first he does three things. First, he repeats what has been said about the nature of the first body and says that for an understanding both of the matters now in question and of matters to be stated later, we must state decisively that the highest body as far as the moon is other than fire and air, as has already been proved, and that there is in that highest body something more pure, and something less pure or sincere, without implying that there is present any composition or mixture of an extraneous nature. Rather "more pure" implies more noble, more virtuous, more formal. Hence it admits of differences both in power and in nobility. This difference is especially evident where it ceases at the air and the lower world surrounding the earth, for in the moon there appear defects of light, and, when it is full, certain dark areas appear.
Secundo ibi: lato autem primo elemento etc., ostendit effectum quem habet corpus superius in inferiora. Et dicit quod primo elemento, idest caelo, circulariter moto, et motis corporibus quae sunt in ipso, idest sole et stellis, illa pars inferioris mundi quae est ei propinquior, quasi disgregata seu rarefacta per motum superioris corporis, accenditur: et sic fit caliditas. Et subiungit rationem, dicens quod hoc oportet intelligere incipiendo.	28. Secondly, at [27] he shows what effect the higher body has upon the lower ones. And he says that by means of the "first element," i.e., the heaven, circularly moved, and the bodies moved in it, namely, sun and stars, that part of the lower world nearest to it, dispersed or rarefied, as it were, by the motion of the superior body, becomes inflamed and heat is produced. And he gives the reason, saying that to understand this we must go back to the beginning.
Tota enim natura corporalis quae est sub corpore circulariter moto, est sicut quaedam materia existens in potentia ad caliditatem, frigiditatem, siccitatem et humiditatem, et ad alias passiones et formas quae consequuntur ad haec: et quia materia reducitur in actum a primo agente, natura etiam corporalis fit talis actu per hoc quod participat de motu vel non participat, sed immobilis permanet, a corpore caelesti, quod supra diximus esse causam et principium unde est motus in istis inferioribus. Non est autem intelligendum quod corpora inferiora recipiant huiusmodi passiones a superioribus tanquam accidentaliter, et non secundum naturam, sicut aqua cum calefit ab igne: sed ipsam naturam vel formam, secundum quam naturaliter sunt calida vel frigida, a superiori corpore recipiunt multo principalius quam a generante; nam primum generationis principium est corpus caeleste.	For the entire bodily nature that exists under the circularly moved body is as a certain matter which is in potency to heat, cold, dryness, and wetness, and to the other passions and forms that result therefrom; and because matter is reduced to act by the first agent, bodily nature also becomes actually such and such by the fact that it participates in the motion, or does not participate but remains immobile, from the heavenly body, which we have previously declared to be the cause and originative principle of the motion in these lower bodies. This does not mean that the lower bodies receive such passions from the superior bodies, as it were, incidentally, and not according to nature, as when water becomes heated by fire; rather, the very nature or form according to which they are naturally hot or cold is received more principally from the superior body than from their generator, for the first principle of generation is the heavenly body.
Tertio ibi: in medio quidem igitur etc., ostendit ordinem elementorum. Si enim per participationem motus fit calor in istis inferioribus, et per elongationem a motu caelesti e converso fit frigus, necesse est quod illud quod est frigidissimum et gravissimum, idest aqua et terra, sit magis remotum a motu caelesti, existens in medio quantum ad terram, et circa medium quantum ad aquam. Vel dicit circa medium, eo quod medium, cum sit indivisibile, non potest esse locus corporis: sed circa medium, idest centrum mundi, est terra et aqua, centrum autem terrae est in centro totius. Circa haec autem, scilicet terram et aquam, et habita his, idest consequenter ordinata post ipsa, est aer et id quod consueto nomine vocamus ignem, in quibus abundat calor.	28 bis. Thirdly [28] he shows the order of the elements. For if heat originates in these lower bodies through participation in motion, and if, on the other hand, cold is due to distance from the heavenly motion, then, of necessity, that which is coldest and heaviest, namely, water and earth, is more removed from the heavenly motion and exists in the middle, as the earth does, or about the middle, as water does. Or else he says, "around the middle," because the middle, being indivisible, cannot be the place of a body, but rather, earth and water are "around the middle," i.e., the center of the world — for the center of the earth is in the center of the whole. "Around these," namely, earth and water, and "had to these," i.e., ordered in sequence after them, are air, and what is commonly called fire, in which [two] heat abounds.
Exponit autem quod dixerat, dicens quod quartum elementum supra aerem ordinatum non proprie vocatur ignis. Ignis enim significat excessum calidi, et est quasi quidam fervor et accensio quaedam; sicut glacies non est elementum, sed est quidam excessus frigoris ad aquam congelatam. Id autem ad quod sic se habet ignis sicut glacies ad aquam, non est nominatum, et ideo nominamus ipsum nomine ignis: sicut si aqua non haberet nomen, et nominaremus elementum aquae glaciem.	He explains his statement that the fourth element, i.e., the one located above air, is not strictly called "fire." For "fire" signifies an excess of heat and is, as it were, a certain intensity and igniting. In the same way, ice is not an element but a certain superabundance of coldness producing congealed water. Now that to which fire is related in the way that ice is related to water has no name; so we call it by the name of fire. It is as though water should have no name and we should call the element of water, "ice."
Sed oportet intelligere quod de toto isto corpore quod a nobis dicitur aer, una pars, quae est propinqua terrae, est quasi calida et humida, propter id quod habet de vapore et exhalatione terrae. Sic enim elementa sunt ordinata, secundum quod eorum naturae competit: unde quia aer secundum naturam suam est calidus et humidus, sic est dispositus ut vaporem terrae suscipiat, ad eius calorem et humiditatem servandam. Sed illa pars corporis quod communiter vocatur aer, quae est superior, est calida et sicca; et hanc partem vocamus elementum ignis. Et sic aer nomen commune est duobus elementis.	But we must understand that in regard to that whole body we call "air," one part, the part nearest the earth, is as though hot and moist on account of vapor, and exhalation from the earth. For the elements are arranged in a manner that befits their nature; therefore, because air is naturally hot and moist, it is disposed to receive vapor from the earth to preserve its heat and moisture. But that part of the body commonly called "air" which is higher, is hot and dry; and this upper part we call the element "fire." In this way the name "air" is common to two elements.
Et quia dixerat de vapore et exhalatione terrae, ostendit differentiam inter ea. Et dicit quod natura vaporis est esse humidum et calidum, natura autem exhalationis est esse calidum et siccum: et sic vapor, propter humiditatem, est quasi in potentia ad aquam; exhalatio autem, propter siccitatem, est quasi in potentia ut igniatur.	And because he had spoken about vapor and exhalation from the earth, he shows the difference between them and says that the nature of vapor is to be moist and hot, whereas the nature of an exhalation is to be hot and dry. As a result, vapor is, on account of its moistness, in potency to water; but an exhalation, on account of its dryness is, as it were, in potency to be ignited.

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Lecture 5 The remaining two questions solved
Chapter 3 cont.
τοῦ μὲν οὖν ἐν τῷ ἄνω τόπῳ μὴ συνίστασθαι νέφη ταύτην ὑποληπτέον αἰτίαν εἶναι, ὅτι οὐκ ἔνεστιν ἀὴρ μόνον ἀλλὰ μᾶλλον οἷον πῦρ.	29 So we must take the reason why clouds are not formed in the upper region to be this: that it is filled not with mere air but rather with a sort of fire.
οὐδὲν δὲ κωλύει καὶ διὰ τὴν κύκλῳ φορὰν κωλύεσθαι συνίστασθαι νέφη ἐν τῷ ἀνωτέρω τόπῳ ῥεῖν γὰρ ἀναγκαῖον ἅπαντα τὸν κύκλῳ ἀέρα, ὅσος μὴ ἐντὸς τῆς περιφερείας λαμβάνεται τῆς ἀπαρτιζούσης ὥστε τὴν γῆν σφαιροειδῆ εἶναι πᾶσαν φαίνεται γὰρ καὶ νῦν ἡ τῶν ἀνέμων γένεσις ἐν τοῖς λιμνάζουσι τόποις τῆς γῆς, καὶ οὐχ (341a.) ὑπερβάλλειν τὰ πνεύματα τῶν ὑψηλῶν ὀρῶν. ῥεῖ δὲ κύκλῳ διὰ τὸ συνεφέλκεσθαι τῇ τοῦ ὅλου περιφορᾷ. τὸ μὲν γὰρ πῦρ τῷ ἄνω στοιχείῳ, τῷ δὲ πυρὶ ὁ ἀὴρ συνεχής ἐστιν ὥστε καὶ διὰ τὴν κίνησιν κωλύεται συγκρίνεσθαι εἰς ὕδωρ, ἀλλ' ἀεὶ ὅ τι ἂν βαρύνηται μόριον αὐτοῦ ἐκθλιβομένου εἰς τὸν ἄνω τόπον τοῦ θερμοῦ κάτω φέρεται, ἄλλα δ' ἐν μέρει συναναφέρεται τῷ ἀναθυμιωμένῳ πυρί, καὶ οὕτω συνεχῶς τὸ μὲν ἀέρος διατελεῖ πλῆρες ὂν τὸ δὲ πυρός, καὶ ἀεὶ ἄλλο καὶ ἄλλο γίγνεται ἕκαστον αὐτῶν.	30 However, it may well be that the formation of clouds in that upper region is also prevented by the circular motion. For the air round the earth is necessarily all of it in motion, except that which is cut off inside the circumference which makes the earth a complete sphere. In the case of winds it is actually observable that they originate in marshy districts of the earth; and they do not seem to blow above the level of the highest mountains. It is the revolution of the heaven which carries the air with it and causes its circular motion, fire being continuous with the upper element and air with fire. Thus its motion is a second reason why that air is not condensed into water. But whenever a particle of air grows heavy, the warmth in it is squeezed out into the upper region and it sinks, and other particles in turn are carried up together with the fiery exhalation. Thus the one region is always full of air and the other of fire, and each of them is perpetually in a state of change.
περὶ μὲν οὖν τοῦ μὴ γίγνεσθαι νέφη μηδ' εἰς ὕδωρ σύγκρισιν, καὶ πῶς δεῖ λαβεῖν περὶ τοῦ μεταξὺ τόπου τῶν ἄστρων καὶ τῆς γῆς, καὶ τίνος ἐστὶν σώματος πλήρης, τοσαῦτα εἰρήσθω.	31 So much to explain why clouds are not formed and why the air is not condensed into water, and what account must be given of the space between the stars and the earth, and what is the body that fills it.
περὶ δὲ τῆς γιγνομένης θερμότητος, ἣν παρέχεται ὁ ἥλιος, μᾶλλον μὲν καθ' ἑαυτὸ καὶ ἀκριβῶς ἐν τοῖς περὶ αἰσθήσεως προσήκει λέγειν (πάθος γάρ τι τὸ θερμὸν αἰσθήσεώς ἐστιν), διὰ τίνα δ' αἰτίαν γίγνεται μὴ τοιούτων ὄντων ἐκείνων τὴν φύσιν, λεκτέον καὶ νῦν.	32 As for the heat derived from the sun, the right place for a special and scientific account of it is in the treatise about sense, since heat is an affection of sense, but we may now explain how it can be produced by the heavenly bodies which are not themselves hot.
ὁρῶμεν δὴ τὴν κίνησιν ὅτι δύναται διακρίνειν τὸν ἀέρα καὶ ἐκπυροῦν, ὥστε καὶ τὰ φερόμενα τηκόμενα φαίνεσθαι πολλάκις.	33 We see that motion is able to dissolve and inflame the air; indeed, moving bodies are often actually found to melt.
τὸ μὲν οὖν γίγνεσθαι τὴν ἀλέαν καὶ τὴν θερμότητα ἱκανή ἐστιν παρασκευάζειν καὶ ἡ τοῦ ἡλίου φορὰ μόνον ταχεῖάν τε γὰρ δεῖ καὶ μὴ πόρρω εἶναι. ἡ μὲν οὖν τῶν ἄστρων ταχεῖα μὲν πόρρω δέ, ἡ δὲ τῆς σελήνης κάτω μὲν βραδεῖα δέ ἡ δὲ τοῦ ἡλίου ἄμφω ταῦτα ἔχει ἱκανῶς.	34 Now the sun's motion alone is sufficient to account for the origin of terrestrial warmth and heat. For a motion that is to have this effect must be rapid and near, and that of the stars is rapid but distant, while that of the moon is near but slow, whereas the sun's motion combines both conditions in a sufficient degree.
τὸ δὲ μᾶλλον γίγνεσθαι ἅμα τῷ ἡλίῳ αὐτῷ τὴν θερμότητα εὔλογον, λαμβάνοντας τὸ ὅμοιον ἐκ τῶν παρ' ἡμῖν γιγνομένων καὶ γὰρ ἐνταῦθα τῶν βίᾳ φερομένων ὁ πλησιάζων ἀὴρ μάλιστα γίγνεται θερμός. καὶ τοῦτ' εὐλόγως συμβαίνει	35 That most heat should be generated where the sun is present is easy to understand if we consider the analogy of terrestrial phenomena, for here, too, it is the air that is nearest to a thing in rapid motion which is heated most. This is just what we should expect, as it is the nearest air that is most dissolved by the motion of a solid body. This then is one reason why heat reaches our world.
μάλιστα γὰρ ἡ τοῦ στερεοῦ διακρίνει κίνησις αὐτόν. διά τε ταύτην οὖν τὴν αἰτίαν ἀφικνεῖται πρὸς τόνδε τὸν τόπον ἡ θερμότης, καὶ διὰ τὸ τὸ περιέχον πῦρ τὸν ἀέρα διαρραίνεσθαι τῇ κινήσει πολλάκις καὶ φέρεσθαι βίᾳ κάτω.	36 Another is that the fire surrounding the air is often scattered by the motion of the heavens and driven downwards in spite of itself.
σημεῖον δ' ἱκανὸν ὅτι ὁ ἄνω τόπος οὐκ ἔστι θερμὸς οὐδ' ἐκπεπυρωμένος καὶ αἱ διαδρομαὶ τῶν ἀστέρων. ἐκεῖ μὲν γὰρ οὐ γίγνονται, κάτω δέ καίτοι τὰ μᾶλλον κινούμενα καὶ θᾶττον, ἐκπυροῦται θᾶττον. πρὸς δὲ τούτοις ὁ ἥλιος, ὅσπερ μάλιστα εἶναι δοκεῖ θερμός, φαίνεται λευκὸς ἀλλ' οὐ πυρώδης ὤν.	37 Shooting-stars further suffix to prove that the celestial sphere is not hot or fiery: for they do not occur in that upper region but below: yet the more and the faster a thing moves, the more apt it is to take fire. Besides, the sun, which most of all the stars is considered to be hot, is really white and not fiery in colour.

Soluta quaestione de ordinatione elementorum, solvit quaestionem de inspissatione nubium. Et ponit duas solutiones. Quarum primam concludit ex praedictis, dicens quod hanc existimandum est esse causam quare in superiori parte aeris non congregantur nubes, quia pars eius superior, quae communiter vocatur aer, non solum est aer, sed magis est quasi ignis, ut dictum est. Sed quia etiam multo inferius infra illam partem adhuc non generantur nubes, necesse fuit ut poneret aliam solutionem.	29. Having solved the question about the order of the elements, he now solves the one about the thickenings which produce clouds. And he gives two solutions, the first of which he derives from the foregoing [29], saying that the cause why clouds are not formed together in the upper region of the air must be considered to be the fact that this upper region, which is commonly called "air," is not only air but is something more akin to fire, as has been said. But because clouds are not formed even much below this region, it was necessary to present another solution.
Unde secundam solutionem ponit ibi: nihil autem prohibet et cetera. Et dicit quod nihil prohibet etiam propter motum aeris in circuitu, prohiberi quod nubes non congregentur in superiori loco: quia necessarium est quod totus aer qui est in circuitu terrae, fluat circulariter motus. Sed ab isto fluxu excipit illum aerem qui capitur inter peripheriam, idest circumferentiam, definitam, idest quae continetur infra partes terrae, ut sic tota terra inveniatur esse sphaerica cum aere incluso inter partes terrae. Et sic ille aer qui excedit omnem altitudinem montium, in circuitu fluit: aer autem qui continetur infra montium altitudinem, impeditur ab hoc fluxu ex partibus terrae immobilibus.	30. Hence he presents a second solution [30] and says that nothing prevents the air's motion in its circuit from inhibiting the gathering of clouds in the upper region; for it is necessary that all the air on the circumference of the earth flow with a circular motion. But he does not include in that flow the air trapped inside the "defined periphery," i.e., the circumference, namely, air enclosed within the parts of the earth, thus making a perfect sphere by virtue of the air enclosed between the parts. Therefore that air exceeding the height of all mountains flows in an orbit, while the air contained below the heights of the mountains is prevented from this flowing, blocked by the immovable parts of the earth.
Et propter hoc generatio ventorum videtur esse nunc in locis terrae stagnantibus, idest in aere qui continetur infra partes terrae, ac si essent stagna aeris quiescentis. Si enim aer in quo generantur venti, moveretur circulariter, oporteret quod omnes venti cum eo circulariter circumferrentur: nunc autem videmus ex diversis partibus ventos flare. Et quia in aere fluenti non generantur venti, sed in quiescenti, propter hoc venti non excedunt montes altos: dicitur enim ab antiquis quod, sacrificiis factis in altissimis montibus, post annum inveniebatur cinis adhuc salvus, in eodem loco manens. Et hoc quod venti non generantur ibi, est signum quod etiam nubes ibi non condensantur in pluvias. Quare autem aer qui excedit montes fluat, ostendit, subdens quod ideo fluit in circuitu, quia simul trahitur cum circulatione caeli: ignis enim est continuus, idest contiguus, cum corpore caelesti, aer autem cum igne.	This is the reason why winds seem now to be generated "in stagnant areas of the earth," i.e., in air which is trapped between the parts of the earth, as though constituting pools of still air. For if the air where winds are born were moved circularly, it would be necessary that all winds accompany it along its circular orbit; but now we observe that winds blow out of diverse regions. And because winds are born not in the flowing air, but in the still air, they never exceed the high mountains; for it is said by the ancients that, when sacrifices were made on the loftiest mountains, the ashes, a year later would be found still in the same place intact. The fact that winds are not generated there is a sign, too, that clouds are not condensed into rain there. But why the air above the mountains flows he explains by saying that the reason it flows along in its course is that it is drawn along by the circling of the heaven; for fire is "continuous," i.e., contiguous, with the heavenly body, and air with fire.
Quia ergo superior aer fluit, per eius motum prohibetur congregari in aquam: quia motus rarefacit et congregationem impedit. Sed si qua pars illius aeris aliquo modo condensetur, aut aliquod spissum aliquo modo feratur per aliquam violentiam, feretur deorsum, idest in locum aeris propinqui terrae: et si quid calidum erat in ea, feretur sursum. Et alia pars illius aeris, quae non gravatur, feretur sursum simul cum igne exhalato. Et sic, dum eorum quae resolvuntur a terris et aquis aliquid manet in loco aeris, aliquid autem fertur ad locum ignis, continue unus locus manet plenus aere, et alius plenus igne: non tamen ita quod semper maneat idem aer et ignis numero incorruptus; sed semper, corrupta una parte aeris vel ignis, vel per violentiam ad terram expulsa, generatur alia, quae sursum a terra et aqua elevatur. Et ita, licet semper maneat in loco aeris aer, et in loco ignis ignis, tamen semper unumquodque ipsorum fit aliud et aliud per continuam generationem et corruptionem; sicut in fluvio decurrenti patet, in quo semper manet aqua, non tamen eadem numero, sed una defluente et alia succedente.	Therefore, because the upper air flows along, its motion prevents its being gathered into water, for movement rarefies things and prevents coalescence. But whenever a portion of that air condenses in some way, something denser is carried along in some way by some constrained motion, it will be carried downward, i.e., to the place of the air close to the earth; and if anything warm was in it, it would be carried upward. And the other part of that air, which did not become heavy, would be carried upward along with the exhaled fire. And so, while, of those things which are resolved out of earth and water, something remains in the region of air, and something is carried upward where fire is, one place continues to be filled with air and another filled with fire; but not in such a way that the same air and fire always remain incorrupt in number. What happens is, rather, that, as one portion of air or fire corrupts or is violently expelled toward the earth, another portion is always generated and rises upward from the earth and from the water. In this way, although there is always air in the region of air, and fire in the region of fire, yet there is always a continual turnover as a result of continuous generation and corruption. An analogy of this is seen in a flowing stream, in which there is always water, yet not the same numerical water, but as some flows on, other flows into its place.
Deinde recolligit ea quae dicta sunt, ibi: de eo quidem igitur etc., et dicit: tanta sunt dicta a nobis de eo quod non fiunt nubes, neque inspissatio vaporum in aquam, in superiori parte aeris; et etiam de hoc, quomodo oporteat accipere de loco qui est inter suprema astra et terram, quo scilicet corpore plenus est.	31. Then [31] he summarizes and says: "So much for what we have to say about the fact that in the upper region of air clouds do not form and no thickening of vapors into water takes place; and also about how we must think of the region between the highest star and the earth, i.e., as to what sort of body it is filled with.
Deinde cum dicit: de facta autem caliditate etc., solvit tertiam quaestionem. Et circa hoc duo facit.	32. Then [32] he solves the third question. About this he does two things:
Primo dicit de quo est intentio: dicens quod de caliditate quam sol facit in istis inferioribus, magis conveniret dicere secundum se et diligenter, idest perfecte, in his quae dicenda sunt in libris de sensu: quia calidum est quaedam sensuum passio, est enim obiectum sensus tactus; sensus autem et sensibile habent eandem scientiam, cum adinvicem dicantur quodammodo. Sed quia materia praesens hoc requirit, dicendum est nunc propter quam causam, cum corpora caelestia non sint calida in sui natura, fit ab eis caliditas in istis inferioribus.	First, he states his intention and says that, as to the heat produced in these lower bodies by the sun, it would be more suitable to discuss this formally and "diligently," i.e., perfectly, among the matters to be discussed in the books dealing with sense; for "hot is a certain passion of the senses, being the object of the sense of touch. But the sense and the sensible object are treated in the same science, for they are in a certain way referred to each other. However, since the matter at hand demands it, we must now discuss why it is that, though heavenly bodies are not hot as to their nature, yet heat is produced by them in these lower bodies.
Secundo ibi: videmus itaque etc., solvit quaestionem. Et dividitur in duas partes:	33. Secondly [33], he solves the question. And it is divided into two parts:
primo ponit quaestionis solutionem; secundo probat verum esse quod in quaestione supponebatur, ibi: signum autem sufficiens et cetera.	First, he presents the solution to the question; Secondly, he proves what he had presupposed in the question, at 37.
Prima dividitur in duas, secundum duas causas quas assignat: secunda incipit ibi: et quia ambiens et cetera.	The first is divided into two parts, according to the two causes assigned; The second begins at 36.
Circa primum tria facit. Primo assignat causam propter quam a corporibus caelestibus non calidis existentibus, calor in istis inferioribus generatur. Et dicit quod sensibiliter videmus quod motus, quia potest disgregare aerem et rarefacere, potest etiam eum ignire: nam raritas et igneitas se consequuntur, sicut frigiditas et spissitudo; et propter hoc ea quae feruntur, sicut sagittae, si habeant plumbum et ceram, saepe videntur liquefieri, quasi motu ea calefaciente. Unde nihil inconveniens est, si caelum suo motu calefacit ista inferiora.	With respect to the first he does three things. First [33] he assigns the cause on account of which heat is generated in these lower bodies by heavenly bodies not themselves hot. And he says that by sense observation we see that movement, since it can separate and rarefy air, can also inflame it: for rarity and combustion go hand in hand, just as do cooling and thickening; and on this account, things borne along, such as arrows, if they include lead and wax, are often seen to melt, as though motion were making them hot. Hence it is not inconceivable that the heaven, by its motion, should heat these lower bodies.
Secundo ibi: eius quidem igitur etc., assignat causam quare calor in istis inferioribus causatur magis ex motu solis, quam ex motu alicuius alterius corporis superioris. Et dicit quod sol solus sufficiens est facere aestuantem calorem in istis inferioribus: nam calor qui fit ex aliis corporibus caelestibus, est quasi insensibilis respectu caloris qui fit a sole. Huius autem ratio est, quia motus qui causat vehementem calorem, oportet quod sit velox, et quod propinquus nobis. Motus autem astrorum tam fixorum quam quinque errantium quae sunt supra solem, secundum opinionem Aristotelis, scilicet Saturni, Iovis, Martis, Veneris et Mercurii, est quidem velox, remotus tamen a nobis longe; motus autem lunae, licet sit propinquus, est tamen tardus; motus autem solis habet utrumque sufficienter ad causandum calorem in istis inferioribus, scilicet et velocitatem et propinquitatem.	34. Secondly [34], he assigns the cause why heat is caused in these lower bodies more by the motion of the sun than by the motion of some other superior body. And he says that the sun by itself suffices to produce a burning heat in these lower bodies: for the heat produced from other heavenly bodies is almost imperceptible when compared to the heat caused by the sun. The reason for this is that if a motion is to cause vehement heat it must be rapid and close to us. Now the motions, both of the fixed stars, and of the five wandering stars [planets], which are, according to Aristotle, above the sun, namely, Saturn, Jupiter, Mars, Venus and Mercury, are indeed rapid, but they are far from us; on the other hand, the motion of the moon, although it is near, is, however, slow. But the motion of the sun has both, i.e., speed and nearness, in a manner sufficient to cause heat in these lower bodies.
Quod autem hic dicitur de velocitate motus solis, referendum est ad motum quo movetur secundum motum diurnum, non ad proprios motus stellarum. Manifestum est enim quod motum diurnum omnia astra eodem temporis spatio peragunt: quanto autem aliquod caelestium corporum est propinquius centro, tanto minorem circumferentiam circuit, unde tardius movetur. Secundum autem proprios motus, luna velocissime movetur.	What is said here about the velocity of the sun's motion is to be referred to its diurnal motion and not to the proper motions of the stars. For it is plain that all the stars complete their diurnal motion during the same period of time: but the closer a heavenly body is to the center, the smaller is the circumference of its orbit and the slower is it moved. But with respect to proper motions, the moon is moved most rapidly.
Tertio ibi: fieri autem magis etc., assignat causam quare magis generatur calor ex motu ipsius solaris corporis, quam ex motu sphaerae eius. Et dicit quod rationabile est quod caliditas fiat magis cum ipso solari corpore. Et huius simile possumus sumere ex his quae sunt apud nos: quia etiam hic, aer vicinus rebus spissis quae feruntur per violentiam, maxime fit calidus. Et hoc accidit etiam rationabiliter: quia maxime motus corporis solidi disgregat aerem; unde cum ipsum corpus solare sit magis solidum quam ceterae partes sphaerae ipsius, cum non sit diaphanum, magis ex motu eius generatur calor, quam ex motu sphaerae eius. Sic igitur propter causam istam caliditas a sole pertingit ad locum istum, quamvis sol non sit calidus.	35. Thirdly [35] he assigns the cause why heat is generated more by the motion of the body of the sun than by the motion of its sphere. And he says that it is reasonable for heat to be produced more by the solar body itself. Something akin to this can be discerned from what happens where we are [on earth]: for here also the air close to thick objects being moved along through violence becomes very hot. And it is reasonable that this should happen: because it is especially the motion of a solid body that dissolves air; hence, since the solar body is more solid than the other parts of its sphere, since it is not diaphanous, heat is generated more from its motion than from the motion of its sphere. This, therefore, explains why heat from the sun reaches this place, even though the sun itself is not hot.
Nec huic causae impedimentum praestat quod luna est inter solem et nos, quae calefieri non potest: quia licet non calefiat a sole, aliquo tamen modo immutatur ab eo, videmus enim quod illuminatur ab eo; non semper autem eadem specie immutationis immutatur medium et extremum, sicut radius solis non inflammat vas vitreum plenum aqua, sed stupam oppositam.	Nor is any obstacle to this cause offered by the presence between us and the sun of the moon which cannot become hot; for although it is not heated by the sun, it is nevertheless influenced in a certain manner by the sun, for we observe that it is illuminated by the sun. Yet a medium and an extreme are not always changed with the same species of change: thus a ray of the sun does not ignite a [magnifying] glass filled with water, but the piece of flax placed beyond.
Apparet etiam ratio quare, ubi est umbra, non est tantus calor quantus est in loco ubi radii solares proiiciuntur: quia scilicet umbra causatur ex aliquo corpore opposito soli, quod interrumpit continuationem transmutationis quae est a sole; sed actio solis pertingit ad locum umbrae per quandam reflexionem.	Also the reason is apparent why, where a shadow is, there is not as much heat as in a place where the sun's rays strike: it is because a shadow is caused by a body blocking the sun and interrupting the continuing transmutation deriving from the sun; however, the action of the sun does reach the place where a shadow is by a sort of reflexion.
Nec tamen putandum est quod motus solis, inquantum est motus tantum, causet calorem: sed inquantum est motus talis corporis, in sua natura habentis virtutem calefaciendi. Omnes enim formae corporum inferiorum reducuntur in corpora caelestia sicut in quaedam principia: et inde est quod diversa corpora caelestia diversos effectus in rebus corporalibus habent, non solum secundum calidum, sed etiam secundum alias passiones et formas.	Nor should it be supposed that the sun's motion, as motion only, causes heat; rather, it is in so far as it is the motion of such a body, i.e., of a body having in its nature the power to cause heat. For all the forms of the lower bodies are reduced back to the heavenly bodies as to certain principles: that is why diverse heavenly bodies produce diverse effects in bodily things, not only so far as heat is considered, but as far as other passions and forms are concerned.
Deinde cum dicit: et quia ambiens etc., ponit propriam causam caliditatis generatae ex motu solis: quae tamen non est universalis, sed particularis. Unde dicit quod frequenter ignis qui ambit inferiores partes mundi, ex motu corporis caelestis, fertur quadam violentiam deorsum, et spargitur per aerem: quia, sicut supra dictum est, superior pars aeris et ignis quendam fluxum habet ex motu caeli.	36. Then [36] he presents a proper cause of heat generated from the motion of the sun: yet not the universal cause but a particular cause. Hence he says that the fire which surrounds the lower parts of the world as a result of a heavenly body's motion is often violently thrust downwards and scattered through the air: because, as was said above, the upper part of the air and fire have a flow on account of the motion of the heaven.
Deinde cum dicit: signum autem sufficiens etc., manifestat quod quaestio supponebat, scilicet quod corpora caelestia non sunt calida aut ignita: et hoc per duo signa. Primum est quia ibi non apparent discursus astrorum quae videntur cadentia, quae ex ignitione generantur in inferiori loco: quod non esset si corpora caelestia essent calida aut ignita; quia ubi est motus maior et velocior, ibi citius aliquid ignitur.	37. Then [37] he shows something which the question supposed, namely, that heavenly-bodies are not hot or fiery; this he does by two signs. The first is that in that region we do not see the paths of those stars which seem to be falling [i.e., shooting stars], which are generated by combustion in the lower regions. This would not be the case if heavenly bodies were hot and fiery, because, wherever there is a greater and speedier motion, there something is ignited more readily.
Secundum signum est quod sol, qui maxime videtur esse calidus ex effectu, videtur coloris albi et non ignei.	The second sign is that the sun, which especially seems to be hot, considering its effects, is seen to be of a white, and not a fiery, color.

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Lecture 6 Shooting stars and meteors — their cause and difference
Chapter 4
(341b.) τούτων δὲ διωρισμένων, λέγωμεν διὰ τίν' αἰτίαν αἵ τε φλόγες αἱ καιόμεναι φαίνονται περὶ τὸν οὐρανὸν καὶ οἱ διαθέοντες ἀστέρες καὶ οἱ καλούμενοι ὑπό τινων δαλοὶ καὶ αἶγες ταῦτα γὰρ πάντ' ἐστὶν τὸ αὐτὸ καὶ διὰ τὴν αὐτὴν αἰτίαν, διαφέρει δὲ τῷ μᾶλλον καὶ ἧττον.	38 Having determined these principles let us explain the cause of the appearance in the sky of burning flames and of shooting-stars, and of 'torches', and 'goats', as some people call them. All these phenomena are one and the same thing, and are due to the same cause, the difference between them being one of degree.
ἀρχὴ δέ ἐστιν καὶ τούτων καὶ πολλῶν ἄλλων ἥδε. θερμαινομένης γὰρ τῆς γῆς ὑπὸ τοῦ ἡλίου τὴν ἀναθυμίασιν ἀναγκαῖον γίγνεσθαι μὴ ἁπλῆν, ὥς τινες οἴονται, ἀλλὰ διπλῆν, τὴν μὲν ἀτμιδωδεστέραν τὴν δὲ πνευματωδεστέραν, τὴν μὲν τοῦ ἐν τῇ γῇ καὶ ἐπὶ τῇ γῇ ὑγροῦ ἀτμίδα, τὴν δ' αὐτῆς τῆς γῆς οὔσης ξηρᾶς καπνώδη καὶ τούτων τὴν μὲν πνευματώδη ἐπιπολάζειν διὰ τὸ θερμόν, τὴν δὲ ὑγροτέραν ὑφίστασθαι διὰ τὸ βάρος. καὶ διὰ ταῦτα τοῦτον τὸν τρόπον κεκόσμηται τὸ πέριξ πρῶτον μὲν γὰρ ὑπὸ τὴν ἐγκύκλιον φοράν ἐστιν τὸ θερμὸν καὶ ξηρόν, ὃ λέγομεν πῦρ (ἀνώνυμον γὰρ τὸ κοινὸν ἐπὶ πάσης τῆς καπνώδους διακρίσεως ὅμως δὲ διὰ τὸ μάλιστα πεφυκέναι τὸ τοιοῦτον ἐκκαίεσθαι τῶν σωμάτων οὕτως ἀναγκαῖον χρῆσθαι τοῖς ὀνόμασιν), ὑπὸ δὲ ταύτην τὴν φύσιν ἀήρ.	39 The explanation of these and many other phenomena is this. When the sun warms the earth the evaporation which takes place is necessarily of two kinds, not of one only as some think. One kind is rather of the nature of vapour, the other of the nature of a windy exhalation. That which rises from the moisture contained in the earth and on its surface is vapour, while that rising from the earth itself, which is dry, is like smoke. Of these the windy exhalation, being warm, rises above the moister vapour, which is heavy and sinks below the other. Hence the world surrounding the earth is ordered as follows. First below the circular motion comes the warm and dry element, which we call fire, for there is no word fully adequate to every state of the fumid evaporation: but we must use this terminology since this element is the most inflammable of all bodies. Below this comes air.
δεῖ δὴ νοῆσαι οἷον ὑπέκκαυμα τοῦτο ὃ νῦν εἴπομεν πῦρ περιτετάσθαι τῆς περὶ τὴν γῆν σφαίρας ἔσχατον, ὥστε μικρᾶς κινήσεως τυχὸν ἐκκαίεσθαι πολλάκις ὥσπερ τὸν καπνόν ἔστι γὰρ ἡ φλὸξ πνεύματος ξηροῦ ζέσις.	40 We must think of what we just called fire as being spread round the terrestrial sphere on the outside like a kind of fuel, so that a little motion often makes it burst into flame just as smoke does: for flame is the ebullition of a dry exhalation.
ᾗ ἂν οὖν μάλιστα εὐκαίρως ἔχῃ ἡ τοιαύτη σύστασις, ὅταν ὑπὸ τῆς περιφορᾶς κινηθῇ πως, ἐκκάεται. διαφέρει δ' ἤδη κατὰ τὴν τοῦ ὑπεκκαύματος θέσιν ἢ τὸ πλῆθος	41 So whenever the circular motion stirs this stuff up in any way, it catches fire at the point at which it is most inflammable. The result differs according to the disposition and quantity of the combustible material.
ἂν μὲν γὰρ πλάτος ἔχῃ καὶ μῆκος τὸ ὑπέκκαυμα, πολλάκις ὁρᾶται καιομένη φλὸξ ὥσπερ ἐν ἀρούρᾳ καιομένης καλάμης, ἐὰν δὲ κατὰ μῆκος μόνον, οἱ καλούμενοι δαλοὶ καὶ αἶγες καὶ ἀστέρες. ἐὰν μὲν πλέον τὸ ὑπέκκαυμα ᾖ κατὰ τὸ μῆκος ἢ τὸ πλάτος, ὅταν μὲν οἷον ἀποσπινθηρίζῃ ἅμα καιόμενον (τοῦτο δὲ γίγνεται διὰ τὸ παρεκπυροῦσθαι, κατὰ μικρὰ μέν, ἐπ' ἀρχὴν δέ), αἲξ καλεῖται, ὅταν δ' ἄνευ τούτου τοῦ πάθους, δαλός. ἐὰν δὲ τὰ μήκη τῆς ἀναθυμιάσεως κατὰ μικρά τε καὶ πολλαχῇ διεσπαρμένα ᾖ καὶ ὁμοίως κατὰ πλάτος καὶ βάθος, οἱ δοκοῦντες ἀστέρες διάττειν γίγνονται. ὁτὲ μὲν οὖν ὑπὸ τῆς κινήσεως ἡ ἀναθυμίασις ἐκκαιομένη γεννᾷ αὐτά ὁτὲ δὲ ὑπὸ τοῦ διὰ τὴν ψύξιν (342a.) συνισταμένου ἀέρος ἐκθλίβεται καὶ ἐκκρίνεται τὸ θερμόν, διὸ καὶ ἔοικεν ἡ φορὰ ῥίψει μᾶλλον αὐτῶν, ἀλλ' οὐκ ἐκκαύσει.	42 If this is broad and long, we often see a flame burning as in a field of stubble: if it burns lengthwise only, we see what are called 'torches' and 'goats' and shooting-stars. Now when the inflammable material is longer than it is broad sometimes it seems to throw off sparks as it burns. (This happens because matter catches fire at the sides in small portions but continuously with the main body.) Then it is called a 'goat'. When this does not happen it is a 'torch'. But if the whole length of the exhalation is scattered in small parts and in many directions and in breadth and depth alike, we get what are called shooting-stars. The cause of these shooting-stars is sometimes the motion which ignites the exhalation. At other times the air is condensed by cold and squeezes out and ejects the hot element; making their motion look more like that of a thing thrown than like a running fire.

Positis his quae ad manifestationem sequentium philosophus induxerat, incipit	38. Having laid down those things introduced to explain what is to follow, the Philosopher begins:
primo determinare de his quae in alto ex materia sicca generantur; secundo de his quae generantur ex materia humida in alto, ibi: de loco autem positione et cetera.	First, to determine concerning things generated on high out of dry matter; Secondly, things generated on high from moist matter (L. 14).
Prima dividitur in tres:	The first is divided into three parts:
primo determinat de stellis cadentibus, et his quae similem habent causam; secundo determinat de cometis, ibi: de cometis autem etc.; tertio de lacteo circulo, qui dicitur Galaxia, ibi: qualiter autem et propter quam causam et cetera.	In the first he determines about falling stars and things having a like cause; In the second about comets (L. 9); In the third about the milky circle called the "galaxy" (L. 12).
Circa primum duo facit:	About the first he does two things:
primo enim determinat de stellis cadentibus et aliis huiusmodi; secundo determinat de quibusdam aliis apparitionibus quae in aere videntur, ibi: apparent autem aliquando nocte et cetera.	First, he determines about falling stars and other similar things; Secondly, about certain other apparitions seen in the air (L. 8).
Circa primum duo facit.	About the first he does two things:
Primo dicit de quo est intentio. Et dicit quod post determinationem praedictorum, dicendum est propter quam causam apparent in caelo flammae accensae, et sidera discurrentia, et vocati a quibusdam dali, idest titiones, et aeges, idest caprae. Ideo autem dicendum est simul de omnibus istis, quia omnia huiusmodi sunt idem secundum speciem, et secundum eandem causam fiunt; sed differunt per magis et minus, ut infra patebit.	First, he states his intention [38] and says that, having determined the foregoing, we must explain the cause of the appearance in the heaven of burning flames and of shooting stars and of so-called dali, i.e., torches, and aeges, i.e., goats. They will be discussed at one and the same time, because they are all alike in kind and produced by the same cause, and differ only in degree, as will be clear below.
Secundo ibi: principium autem et horum etc., determinat propositum. Et circa hoc duo facit.	39. Secondly [39], he determines his proposition, about which he does two things:
Primo praemittit causas generationis praedictorum. Et dicit quod principium praedictarum passionum et multarum aliarum, tam activum quam materiale, est quod dicetur. Cum enim terra calefacta fuerit per motum solis, oportet aliquam exhalationem resolvi a terra. Quae non est uniusmodi, ut quidam putant, sed est duplex: quaedam enim est magis vaporosa et humida, quaedam vero est magis spumosa et sicca: nam ab humido aqueo quod est super terram, resolvitur et elevatur vaporosa exhalatio et humida; ab ipsa autem terra, quae est siccae naturae, elevatur exhalatio fumosa sive spumosa. Harum autem exhalationum, spumosa quidem supereminet propter calidum, quod in ea dominatur et magis ipsam subtiliat: siccum enim et calidum leve est, et talis est ignis natura. Vaporosa autem exhalatio, quae est magis humida, subest spumosae propter pondus, non enim ita rarefit: calidum enim et humidum pertinent ad naturam aeris, qui subest igni calido et sicco existenti.	First, he states the causes generating the aforesaid, and says that the principle, both active and passive, of the aforesaid phenomena and of many others is what he will indicate. For when the earth has been warmed by the sun's motion, a certain exhalation is necessarily released from the earth. This is not of one sort, as some think, but is twofold: one is more vaporous and moist, the other more foam-like and dry — for from the aqueous moisture upon the earth's surface there is released and lifted on high a vaporous exhalation which is moist; from the earth itself, which is by nature dry, there is raised a fume-like or foam-like exhalation. Of these, the foam-like exhalation rises above the other on account of warmth which dominates in it and renders it more subtle: for the dry and warm is light — and fire is of this nature. But the vaporous exhalation, which is more moist, finds its place under the foam-like, being heavier, for it is not so fine: hot and moist pertain to the nature of the air, which is below fire, which is hot and dry.
Et huic attestatur ordo elementorum quae sunt circa terram. Nam sub circulari motu caeli primo est locatum id quod est calidum et siccum, quod communiter dicitur ignis, licet non sit nomen proprium, ut supra dictum est: quia enim id quod est commune omni fumosae exhalationi, est innominatum, et quod tale est maxime natum est exuri, propter hoc sic necessarium fuit uti nominibus, ut talis fumosa exhalatio ignis diceretur. Sub fumosa autem exhalatione est aer. Sic ergo posita est causa et effectiva praedictarum passionum, quae est latio solis, et causa materialis, quae est fumosa exhalatio.	The very order of the elements surrounding the earth attests to this. For under the circular motion of the heaven there is first located what is hot and dry and which is commonly called "fire," though that is not its proper name, as has been said above: for, since the item common to every smoky exhalation has no name, and such is especially apt to burn, consequently, it was necessary to use words in keeping, and so such a fume-like evaporation comes to be called "fire." Under this fume-like exhalation is air. Thus we have posited both the effective cause of the aforesaid passions, which is the sun's movement, and the material cause, namely, the fume-like exhalation.
Secundo ibi: oportet autem intelligere etc., determinat de generatione praedictarum passionum. Et circa hoc duo facit:	40. Secondly [40], he determines concerning the generation of the aforesaid passions. About this he does two things:
primo assignat rationem generationis harum passionum; secundo assignat rationem quorundam accidentium circa ipsas, ibi: propter positionem et cetera.	First, he assigns the cause of their generation; Secondly, the reason why certain things accompany them, at 47.
Circa primum tria facit:	About the first he does three things:
primo assignat causam praedictarum passionum in communi; secundo assignat differentiam earum adinvicem, ibi: quacumque igitur se habeat maxime etc.; tertio movet dubitationem circa determinata, ibi: dubitabit utique quis et cetera.	First, he gives the cause of the aforesaid passions in common; Secondly, their mutual differences, at 41; Thirdly, he raises a question concerning what he has determined (L. 7).
Dicit ergo primo quod, secundum praedicta, oportet intelligere hoc quod nunc diximus ignem, scilicet fumosam exhalationem, esse ut quoddam hyppeccauma, idest quandam materiam incendii; et quod ordinatur in rotunditate quae est circa terram ultimo (incipiendo scilicet a terra); ita quod propter propinquitatem ad motum caelestem, saepe exuratur, sortiens augmentum caloris, modico motu, idest cum parum movetur ex motu superioris corporis; sicut accidit de fumo, dum incenditur et fit flamma: nihil enim est aliud flamma quam ardor spiritus, idest fumi, sicci. Ipsa ergo flammatio praedicti hypeccaumatis, communiter loquendo, est generatio praedictarum passionum, ex appropinquatione materiae praeparatae causae efficienti.	He says therefore first [40] that, in the light of the foregoing, we must understand what we have just now called "fire" to be as a certain "fuel," i.e., a combustible material, and that it is situated in the sphericity which is about the earth in the last place (beginning, that is, from the earth), Hence, on account of its proximity to the heavenly motion it often bursts into flame, being heated when only "slightly moved," i.e., when slightly stirred by the motion of the body above it, as happens in the case of smoke, when it is ignited and becomes flame: for a flame is nothing but the burning of a dry "spirit," i.e., smoke. Therefore the ignition of the above-mentioned fuel, commonly speaking, is responsible for the generation of the aforesaid passions, when matter which is prepared is placed in the proximity of the efficient cause.
Deinde cum dicit: quacumque igitur se habeat maxime etc., assignat differentiam praedictarum passionum. Et circa hoc duo facit.	41. Then [41] he explains the differences among the aforesaid passions. About this he does two things:
Primo ostendit unde sit accipienda differentia. Et dicit quod ex qua parte se habet praedicta materia (quocumque modo se habeat talis consistentia, idest praedicta materia incendii) optime disposita ad hoc quod igniatur, tali modo exuritur, quando fuerit mota per calefactionem a circulari motu caeli: et differt passio exignita secundum positionem praedictae materiae et multitudinem.	First he shows what is the basis for the difference. And he says that from whatever source the aforesaid matter is had (regardless of how this "consistency" is obtained, namely, the aforesaid matter for burning), and when it is most perfectly disposed to be ignited, then it is so ignited in such a way by heating from the circular motion of the heaven: and the ignited passion varies according to the position and amount of the aforesaid matter.
Secundo ibi: si quidem enim etc., assignat differentiam praedictarum passionum. Et dicit quod si praedicta materia habeat magnam latitudinem et longitudinem, videtur esse quaedam flamma accensa in caelo, sicut cum stipula ardet in area. Si vero non habeat multum in latitudine, sed solum in longitudine, generantur et apparent illic dali, idest titiones, et aeges, idest caprae, et sidera discurrentia. Quia si praedicta materia fuerit plus secundum longitudinem quam latitudinem, et quando simul dum comburitur, ignis scintillat, idest videtur salire et discurrere quasi aeges, idest sicut caprae (quod quidem fit propter hoc quod incipit igniri non tota materia simul, sed secundum aliquas parvas partes, incipiens ex aliquo principio illius materiae): quando inquam hoc fit, tunc vocatur aeges, idest capra. Sed quando fit incensio praedictae materiae sine praedicta passione, idest sine scintillatione, eo quod materia tota accenditur simul, tunc vocatur dalus, idest titio.	42. Secondly [42], he determines the differences among the aforesaid passions. And he says that if the aforesaid matter has great width and length, there appears to be a certain flame enkindled in the heaven, similar to stubble burning in a field [area]. But if it does not have great width, but only length, then "dali," i.e., torches, and "aeges," i.e., goats, and shooting stars are generated and appear there. For if the aforesaid matter is more in length than in width, and when it burns, the fire "scintillates," i.e., seems to leap and run about like "aeges," i.e., goats (which happens because not all the matter begins to be ignited at once but according to certain small sections, beginning from some starting-point in the matter), when, I say, this happens, it is called "aeges," i.e., a goat. But when the burning of the aforesaid matter takes place without the aforesaid passion, i.e., without scintillation, because the entire material is ignited at once, then it is called a "dalus," i.e., a torch.
Sed quando exhalatio non fuerit continua, sed frequens et dispersa per modicas partes et multis modis, tam secundum longitudinem quam secundum latitudinem, quam etiam secundum profunditatem, tunc fiunt sidera quae putantur volare: eo quod illa materia cito consumitur, et desinit esse ibi ubi prius accensa fuerat, sicut accidit de stuppa, si modicum de ea per longitudinem disponatur et accendatur: currit enim combustio, et videtur similis esse motui alicuius corporis ignei.	However, when the exhalation is not continuous, but frequent, and scattered in small areas, and in many ways, both according to length and according to width and even depth, then appear stars that seem to fly, because the material is rapidly consumed and ceased to be where it was previously burning, as happens with flax, if a small amount of it is laid down lengthwise and ignited: for the combustion seems to run along and seems similar to the movement of some fiery body.
Sic igitur patet quod plurimum habet de materia flamma accensa; mediocriter (propter quod vocantur) titiones et caprae; minimum autem stellae discurrentes, et propter hoc frequentius apparent.	In this way, it is therefore plain that the burning flame has most material; a medium amount what are called "torches" and "goats," and least for shooting stars, which accounts for their rather frequent occurrence.
Sed quia sidera volantia habent aliam causam suae generationis, ideo subiungit quod aliquando exhalatio exusta a motu solis generat ea; aliquando autem, inspissato aere propter frigus, illud quod est ibi calidum, inspissatum extruditur inferius et separatur a frigido; et propter hoc illud inspissatum ignitur, et videtur stella cadens. Propter quod et motus siderum sic cadentium non assimilatur exustioni, sed magis proiectioni.	43. But because shooting stars have an additional cause of their generation, he adds that sometimes an exhalation ignited by the sun's movement generates them, but sometimes, too, when cold causes air to thicken, that which is hot within, being thickened, is forced out downward and is separated from the cold; this causes the thickened mass to ignite and a falling star is seen. That is also why the motion of stars falling in that way is not assimilated to a burning, but rather to a projecting.

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Lecture 7 Solution of problems concerning shooting stars
Chapter 4 cont.
ἀπορήσειε γὰρ ἄν τις πότερον ὥσπερ ἡ ὑπὸ τοὺς λύχνους τιθεμένη ἀναθυμίασις ἀπὸ τῆς ἄνωθεν φλογὸς ἅπτει τὸν κάτωθεν λύχνον (θαυμαστὴ γὰρ καὶ τούτου ἡ ταχυτής ἐστιν καὶ ὁμοία ῥίψει, ἀλλ' οὐχ ὡς ἄλλου καὶ ἄλλου γιγνομένου πυρός), ἢ ῥίψεις τοῦ αὐτοῦ τινος σώματός εἰσιν αἱ διαδρομαί.	43 For the question might be raised whether the 'shooting' of a 'star' is the same thing as when you put an exhalation below a lamp and it lights the lower lamp from the flame above. For here too the flame passes wonderfully quickly and looks like a thing thrown, and not as if one thing after another caught fire. Or is a 'star' when it 'shoots' a single body that is thrown?
ἔοικε δὴ δι' ἄμφω καὶ γὰρ οὕτως ὡς ἡ ἀπὸ τοῦ λύχνου γίγνεται, καὶ ἔνια διὰ τὸ ἐκθλίβεσθαι ῥιπτεῖται, ὥσπερ οἱ ἐκ τῶν δακτύλων πυρῆνες, ὥστε καὶ εἰς τὴν γῆν καὶ εἰς τὴν θάλατταν φαίνεσθαι πίπτοντα, καὶ νύκτωρ καὶ μεθ' ἡμέραν καὶ αἰθρίας οὔσης. κάτω δὲ ῥιπτεῖται διὰ τὸ τὴν πύκνωσιν εἰς τὸ κάτω ῥέπειν τὴν ἀπωθοῦσαν. διὸ καὶ οἱ κεραυνοὶ κάτω πίπτουσιν, <�τοῦ πυρὸς ἄνω φερομένου κατὰ φύσιν> πάντων γὰρ τούτων ἡ γένεσις οὐκ ἔκκαυσις ἀλλ' ἔκκρισις ὑπὸ τῆς ἐκθλίψεώς ἐστιν, ἐπεὶ κατὰ φύσιν γε τὸ θερμὸν ἄνω πέφυκε φέρεσθαι πᾶν.	44 Apparently both cases occur: sometimes it is like the flame from the lamp and sometimes bodies are projected by being squeezed out (like fruit stones from one's fingers) and so are seen to fall into the sea and on the dry land, both by night and by day when the sky is clear. They are thrown downwards because the condensation which propels them inclines downwards. Thunderbolts fall downwards for the same reason: their origin is never combustion but ejection under pressure, since naturally all heat tends upwards.
ὅσα μὲν οὖν μᾶλλον ἐν τῷ ἀνωτάτω τόπῳ συνίσταται, ἐκκαιομένης γίγνεται τῆς ἀναθυμιάσεως, ὅσα δὲ κατώτερον, ἐκκρινομένης διὰ τὸ συνιέναι καὶ ψύχεσθαι τὴν ὑγροτέραν ἀναθυμίασιν αὕτη γὰρ συνιοῦσα καὶ κάτω ῥέπουσα ἀπωθεῖ πυκνουμένη καὶ κάτω ποιεῖ τοῦ θερμοῦ τὴν ῥῖψιν	45 When the phenomenon is formed in the upper region it is due to the combustion of the exhalation. When it takes place at a lower level it is due to the ejection of the exhalation by the condensing and cooling of the moister evaporation: for this latter as it condenses and inclines downward contracts, and thrusts out the hot element and causes it to be thrown downwards.
διὰ δὲ τὴν θέσιν τῆς ἀναθυμιάσεως, ὅπως ἂν τύχῃ κειμένη τοῦ πλάτους καὶ τοῦ βάθους, οὕτω φέρεται ἢ ἄνω ἢ κάτω ἢ εἰς τὸ πλάγιον. τὰ πλεῖστα δ' εἰς τὸ πλάγιον διὰ τὸ δύο φέρεσθαι φοράς, βίᾳ μὲν κάτω, φύσει δ' ἄνω πάντα γὰρ κατὰ τὴν διάμετρον φέρεται τὰ τοιαῦτα. διὸ καὶ τῶν διαθεόντων ἀστέρων ἡ πλείστη λοξὴ γίγνεται φορά. πάντων δὴ τούτων αἴτιον ὡς μὲν ὕλη ἡ ἀναθυμίασις, ὡς δὲ τὸ κινοῦν ὁτὲ μὲν ἡ ἄνω φορά, ὁτὲ δ' ἡ τοῦ ἀέρος συγκρινομένου πῆξις.	46 The motion is upwards or downwards or sideways according to the way in which the evaporation lies, and its disposition in respect of breadth and depth. In most cases the direction is sideways because two motions are involved, a compulsory motion downwards and a natural motion upwards, and under these circumstances an object always moves obliquely. Hence the motion of 'shooting-stars' is generally oblique. So the material cause of all these phenomena is the exhalation, the efficient cause sometimes the upper motion, sometimes the contraction and condensation of the air.
πάντα δὲ κάτω ταῦτα σελήνης γίγνεται. σημεῖον δ' ἡ φαινομένη αὐτῶν ταχυτὴς ὁμοία οὖσα τοῖς ὑφ' ἡμῶν ῥιπτουμένοις, ἃ διὰ τὸ πλησίον εἶναι ἡμῶν πολὺ δοκεῖ τῷ τάχει παραλλάττειν ἄστρα τε καὶ ἥλιον καὶ σελήνην.	47 Further, all these things happen below the moon. This is shown by their apparent speed, which is equal to that of things thrown by us; for it is because they are close to us, that these latter seem far to exceed in speed the stars, the sun, and the moon.

Quia assignavit duas causas generationis siderum discurrentium, hic movet quandam dubitationem circa ea. Et circa hoc duo facit.	44. Because he assigned two causes for the generation of shooting stars, he now raises a certain problem about them. With respect to this he does two things:
Primo movet dubitationem: quae est utrum discursus siderum currentium fiat hoc modo, sicut cum fumosa exhalatio inferioris candelae incenditur a flamma superioris candelae vel lucernae (tunc enim videtur ignis descendere cum mirabili velocitate, et videtur proiectio unius et eiusdem ignis, et non videtur quod ignis fiat in alio et alio corpore); aut secundum veritatem discursus siderum cadentium sunt proiectiones alicuius eiusdem corporis cadentis.	First, he raises the problem [43] which is this: whether the trajectory of shooting stars is the same as when the smoke-like exhalation of a lower candle is set afire by the flame of a higher candle or light (for in such a case the fire is seen to travel downward with marvelous speed and there appears to be the projection of one and the same fire instead of fire igniting in two distinct bodies); or whether the truth is that the trajectories of falling-stars are the projections of some same falling body.
Secundo ibi: videtur itaque etc., solvit propositam dubitationem. Et circa hoc duo facit.	45. Secondly [45], he solves this problem. Concerning it he does two things:
Primo dicit quod propter utramque causam videtur esse discursus siderum cadentium. Quandoque enim sic fit talis discursus per continuam ignitionem materiae, sicut dictum est de fumo lucernarum: quandoque autem aliqua ignita proiiciuntur, propter hoc quod expelluntur a superiori frigore, sicut cum aliqua cadunt expulsa ex digitis, ut nux cerasii. Unde et in terram et in mare videntur cadentia, et hoc tam in die quam in nocte, serenitate existente. Dicit autem de die, et non solum per noctem, quia huiusmodi ignis cadens, nisi appropinquaret terrae per motum, non appareret de die. Dicit autem serenitate existente, quia tempore nebuloso talis ignis ab humiditate nubium et aeris extingueretur.	First, he says that the trajectories of falling stars seem to be due to both causes. For sometimes such a trajectory results from the continuous enkindling of matter, as was said of the smoke from lamps; but sometimes certain ignited substances are projected out as the result of being expelled by a higher coldness, much like a cherry pit squeezed out by one's fingers. Hence they are seen falling into the earth and sea, during the day as well as the night, when the sky is clear. He says, "during the day" and not at night only, because unless such a falling fire approached the earth through movement, it would not be visible during the day. Likewise he says, "when the sky is clear," because when is is cloudy, such fire would be snuffed out by the humidity of the clouds and air.
Sed licet ista quae cadunt expulsa sint ignita, et ita, ut videtur, deberent esse levia et ascendere, tamen deorsum iaciuntur, quia coagulatio frigoris impellens ea inclinat deorsum. Et propter hanc causam fulmina cadunt deorsum, licet sint ignita: quia generatio omnium horum sic cadentium non est per exustionem ab aliquo calido igniente, sed per separationem ab aliquo frigido expellente; quia omne calidum secundum naturam habet ferri sursum.	But although those things expelled are on fire, and should, it would seem, on that account have to be light and therefore ascend, they are nevertheless cast downwards, because the condensation of cold driving them inclines them downwards. This is the reason why thunderbolts fall downwards even though ignited: for the generation of all things falling in this way is due, not to their being set afire by something hot which ignites them, but to their being detached by something cold which expels them — since by nature everything hot is borne aloft.
Secundo ibi: quaecumque quidem igitur etc., assignat differentiam inter discursus siderum ex duabus causis provenientes. Et dicit quod quaecumque siderum discurrentium magis generantur in supremo loco, fiunt per adustionem exhalationis: quaecumque vero demissius generantur, fiunt propter hoc quod humidior exhalatio concernitur, idest inspissatur, et infrigidatur. Haec enim humida exhalatio congregata deorsum tendens, impellit et quasi proiicit calidum deorsum, cum aliqua materia inspissata.	46. Secondly [45], he explains the difference between the trajectories of the stars arising from these two causes. And he says that whatever shooting stars are generated more in the highest region, these are caused by the combustion of an exhalation; but the ones generated farther down are caused by the moister exhalation "mixing together," i.e., condensing and cooling. For this moist exhalation, now concentrated and inclining downwards, pushes and, as it were, thrusts downward the hot element, together with some condensed matter.
Deinde cum dicit: propter positionem etc., assignat rationem quorundam accidentium circa praedicta. Et circa hoc duo facit:	47. Then [46] he explains certain phenomena accompanying these events. About this he does two things:
primo assignat rationem de modo motus huiusmodi astrorum cadentium, secundum dispositionem ipsorum; secundo determinat locum generationis eorum, ibi: omnia autem haec sub luna et cetera.	First, he explains the reason for the type of motion of such falling stars; Secondly, he determines the place where they are generated, at 48.
Dicit ergo primo quod secundum diversam positionem exhalationis in latitudine et profunditate, secundum hoc diversimode fertur stella cadens, aut sursum aut deorsum aut ad latus expulsionis a frigore. Quia si materia frigida inspissata expellens fuerit adunata sursum, stella cadens per expulsionem fertur deorsum; si autem fuerit adunata inferius, fertur sursum; cum autem ex neutra parte adunatur, tunc fertur ad latus, quasi oblique et in diametrum. Et hoc pluries evenit: quia calidum expulsum fertur duabus lationibus; naturaliter enim, inquantum est calidum, fertur sursum, sed per violentiam expulsionis fertur deorsum; omnia autem talia, quorum motus sic compositi sunt, feruntur secundum diametrum, idest oblique, quia talis motus est quasi medius inter ascensum et descensum. Et ideo motus discurrentium siderum ut plurimum fit obliquus.	He says therefore first that, depending on the different position of the exhalation with respect to the sides or depth [i.e., top or bottom], the falling star will be moved differently — either above or below, or to the side, of its point of ejection by the cold. For if the condensed cold matter which does the ejecting has come together above, the falling star is moved downward by the expulsion; but if the matter has collected below, then it is moved upward; if it comes together in neither place, then its [the star's] motion is sideways, as though obliquely or along the diameter. And this often happens: for the ejected hot mass is moved with two motions: by nature, as hot, it is moved upwards; but through the violence of the ejection, it is moved downwards. But all such things, whose motions are so combined, are moved "according to the diameter," i.e., obliquely, since such a motion is as though a mean between ascent and descent. As a result the motion of falling stars is most often oblique.
His autem dictis, epilogat quae dicta sunt. Et dicit quod omnium praedictorum causa materialis est exhalatio: causa autem movens est duplex; quandoque quidem motus superioris corporis, quandoque autem condensatio aeris inspissati ex frigore, et ex hoc expellentis calidum.	Then he summarizes what has been set forth and says that the material cause of all the foregoing is an exhalation; but the movent cause is twofold: for sometimes it is the movement of a higher body, sometimes it is the condensing of air thickened by coldness, and subsequently forcing out the hot.
Deinde cum dicit: omnia autem haec sub luna etc., determinat locum generationis praedictorum. Et dicit quod omnia praedicta generantur sub luna. Cuius signum est quod apparent nobis valde velociter moveri, sicut illa quae proiiciuntur a nobis, utpote sagittae et alia huiusmodi, quae propter propinquitatem ad nos videntur excedere velocitatem astrorum et solis et lunae; quamvis manifestum sit quod, secundum rei veritatem, superiora corpora multo velocius moventur quam aliquid quod sit hic.	48. Then [47] he determines the place where the aforesaid are produced and says that they are all produced below the moon. A sign of this is that they appear to us to be moving very rapidly, as do things we project, such as arrows and the like, which, for being close to us, seem to be travelling faster than the stars and sun and moon — although it is plain that, in truth, the higher bodies are moved much faster than anything here.

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Lecture 8 Cause of other phenomena appearing at night, and of certain that do not
Chapter 8
φαίνεται δέ ποτε συνιστάμενα νύκτωρ αἰθρίας οὔσης πολλὰ φάσματα ἐν τῷ οὐρανῷ, οἷον χάσματά τε καὶ βόθυνοι καὶ αἱματώδη χρώματα.	48 Sometimes on a fine night we see a variety of appearances that form in the sky: 'chasms' for instance and 'trenches' and blood-red colours.
αἴτιον δὲ ἐπὶ τούτων τὸ (342b.) αὐτό ἐπεὶ γὰρ φανερός ἐστι συνιστάμενος ὁ ἄνω ἀὴρ ὥστ' ἐκπυροῦσθαι, καὶ τὴν ἐκπύρωσιν ὁτὲ μὲν τοιαύτην γίγνεσθαι ὥστε φλόγα δοκεῖν καίεσθαι, ὁτὲ δὲ οἷον δαλοὺς φέρεσθαι καὶ ἀστέρας, οὐδὲν ἄτοπον εἰ χρωματίζεται ὁ αὐτὸς οὗτος ἀὴρ συνιστάμενος παντοδαπὰς χρόας διά τε γὰρ πυκνοτέρου διαφαινόμενον ἔλαττον φῶς καὶ ἀνάκλασιν δεχόμενος ὁ ἀὴρ παντοδαπὰ χρώματα ποιήσει, μάλιστα δὲ φοινικοῦν ἢ πορφυροῦν, διὰ τὸ ταῦτα μάλιστα ἐκ τοῦ πυρώδους καὶ λευκοῦ φαίνεσθαι μειγνυμένων κατὰ τὰς ἐπιπροσθήσεις, οἷον ἀνίσχοντα τὰ ἄστρα καὶ δυόμενα, ἐὰν ᾖ καῦμα, καὶ διὰ καπνοῦ φοινικᾶ φαίνεται. καὶ τῇ ἀνακλάσει δὲ ποιήσει, ὅταν τὸ ἔνοπτρον ᾖ τοιοῦτον ὥστε μὴ τὸ σχῆμα ἀλλὰ τὸ χρῶμα δέχεσθαι. τοῦ δὲ μὴ πολὺν χρόνον μένειν ταῦτα ἡ σύστασις αἰτία ταχεῖα οὖσα.	49 These, too, have the same cause. For we have seen that the upper air condenses into an inflammable condition and that the combustion sometimes takes on the appearance of a burning flame, sometimes that of moving torches and stars. So it is not surprising that this same air when condensing should assume a variety of colours. For a weak light shining through a dense air, and the air when it acts as a mirror, will cause all kinds of colours to appear, but especially crimson and purple. For these colours generally appear when fire-colour and white are combined by superposition. Thus on a hot day, or through a smoky, medium, the stars when they rise and set look crimson. The light will also create colours by reflection when the mirror is such as to reflect colour only and not shape. These appearances do not persist long, because the condensation of the air is transient.
τὰ δὲ χάσματα ἀναρρηγνυμένου τοῦ φωτὸς ἐκ κυανοῦ καὶ μέλανος ποιεῖ τι βάθος ἔχειν δοκεῖν. πολλάκις δ' ἐκ τῶν τοιούτων καὶ δαλοὶ ἐκπίπτουσιν, ὅταν συγκριθῇ μᾶλλον συνιὸν δ' ἔτι χάσμα δοκεῖ.	50 'Chasms' get their appearance of depth from light breaking out of a dark blue or black mass of air. When the process of condensation goes further in such a case we often find 'torches' ejected. When the 'chasm' contracts it presents the appearance of a 'trench'.
ὅλως δ' ἐν τῷ μέλανι τὸ λευκὸν πολλὰς ποιεῖ ποικιλίας, οἷον ἡ φλὸξ ἐν τῷ καπνῷ. ἡμέρας μὲν οὖν ὁ ἥλιος κωλύει, νυκτὸς δ' ἔξω τοῦ φοινικοῦ τὰ ἄλλα δι' ὁμόχροιαν οὐ φαίνεται.	51 In general, white in contrast with black creates a variety of colours; like flame, for instance, through a medium of smoke. But by day the sun obscures them, and, with the exception of crimson, the colours are not seen at night because they are dark.
περὶ μὲν οὖν τῶν διαθεόντων ἀστέρων καὶ τῶν ἐκπυρουμένων, ἔτι δὲ τῶν ἄλλων τῶν τοιούτων φασμάτων ὅσα ταχείας ποιεῖται τὰς φαντασίας, ταύτας ὑπολαβεῖν δεῖ τὰς αἰτίας.	52 These then must be taken to be the causes of 'shooting-stars' and the phenomena of combustion and also of the other transient appearances of this kind.

Postquam philosophus assignavit causam accensionum quae videntur moveri in aere, hic assignat causam quorundam aliorum nocte apparentium. Et circa hoc duo facit.	49. After assigning the cause of the conflagrations that are seen being moved in the air, the Philosopher here assigns the cause of certain other things that appear at night. About this he does two things:
Primo proponit illa quorum causas assignare intendit. Et dicit quod aliquando apparent in nocte, cum fuerit serenitas, phantasmata, idest apparitiones, in caelo; sicut hiatus, idest quaedam aperturae, ac si caelum esset apertum, et bothyni, idest voragines, quasi profundae aperturae, et etiam sanguinei colores.	First, he enumerates the things whose causes he intends to assign and says that sometimes at night, when it is clear, "phantoms," i.e., apparitions, are visible in the heaven: for instance, "crevices," i.e., gashes, as though the sky were open, and "bothyni," i.e., chasms, as though deep breaches, and also "blood-red colors."
Secundo ibi: causa autem et in his etc., assignat causas horum. Et circa hoc duo facit:	50. Secondly, he assigns the causes of these things. About this he does two things:
primo assignat causam quare appareant praedicta; secundo quare multa alia fiunt quae non apparent, ibi: omnino autem in nigro album et cetera.	First, he gives the cause of their appearance, at 50; Secondly, why many other things occur that are not visible, at 52.
Circa primum duo facit:	About the first he does two things:
primo assignat causam colorum; secundo assignat causam hiatus et voraginis, ibi: hiatus autem et cetera.	First, he assigns the cause of the colors; Secondly, the cause of the crevices and chasms, at 51.
Dicit ergo primo quod eadem causa est in his apparitionibus, quae etiam est ignitionum de quibus supra dictum est. Cum enim manifestum sit quod aer superior (quem supra dixit hypeccauma) sic disponitur quod in eo fiat ignitio; quae quidem aliquando talis est ut videatur ardere flamma, quandoque autem taliter fit ignitio ut videantur ferri titiones et sidera; nullum est inconveniens, cum incensiones fiant in aere multiformes, quod ille aer superior coloratus appareat omni genere colorum.	He says therefore first [49] that the causes of these apparitions and of the conflagrations discussed earlier are the same. For since it is plain that the upper air (which he earlier called "fuel") is so disposed as to be able to be ignited, so that sometimes a flame appears to burn, and sometimes it is ignited to give the appearance of moving torches and stars, it is not strange (since many varieties of ignitings occur in the air) that the upper air should appear colored with every variety of color.
Duobus enim modis contingit quod aer aliquatenus inspissatus omnes modos colorum repraesentet: uno modo quando aliquod minus lumen, quod non sufficit totaliter illuminare, transparet per aliquem fumum aut vaporem spissiorem; alio modo quando fit repercussio luminis ad aliquem aerem aliquatenus inspissatum. Sed maxime ex istis duabus causis apparent in aere color puniceus et purpureus, idest rubeus et subrubeus: quia maxime hi colores apparent ex aliquo igneo et albo mixtis nigro.	For there are two ways in which air somewhat thickened comes to represent all varieties of colors: one way is when a feeble light, which is not enough to illuminate fully, shines through smoke or thick vapor; another way is when light is reflected off somewhat thickened air. From these two causes especially, there appears in the air a crimson and purple color, i.e., reddish and sub-red — for these colors appear especially when things fiery and white are mixed with black.
Quae quidem mixtio potest fieri secundum duas supradictas causas: scilicet secundum superappositiones (quod supra dixit transparentiam minoris luminis per aliquod spissius), sicut sol et luna et alia astra apparent punicea in ortu et occasu et quasi subrubea, quando eorum lumen non est perfectum. Sed hoc dico si fuerit calor: quia quando est frigus, vapores sunt condensati, et magis obscurant lumen astrorum orientium vel occidentium, ut transparere non possit; quando autem est calor, exhalationes sunt rariores, et sic per eas lumen astrorum transparere potest. Et similiter si astra videantur mediante fumo, videntur talis coloris.	Such a mixture can occur as a result of the two above-mentioned causes: namely, by "superapposition" (described above as a feeble light shining through something fairly thick — as when the sun and the moon and other stars appear crimson when they rise and set, and as though sub-red when their light is not perfect). But I say this, if heat is present: because when it is cold, vapors are condensed and obscure the light of rising and setting stars more, so that it cannot get through; but when it is hot, the exhalations are finer and permit the light of the stars to pass through. Likewise, if the stars are seen through smoke, they have this color.
Et secundum etiam aliam praedictam causam fit praedicta mixtio, scilicet per refractionem; cum illud ad quod fit refractio luminis (quod hic speculum dicit), sive sit nubes aquosa sive aliquid huiusmodi, fuerit tale ut non repraesentet figuram, sed colorem. Haec autem exponet cum de iride agetur.	This mixture can also be produced by the other cause mentioned: namely, refraction, when the object from which the light is refracted (he here calls this object a "mirror"), whether it be a water-soaked cloud or something other of the same sort, is of such a nature as to reveal color but not shape. He will explain this, when it is question of the rainbow.
Assignat autem causam consequenter quare huiusmodi colores cito disparent et non multo tempore manent: quia scilicet causa apparitionis ipsorum est velox, idest cito pertransiens; aer enim non multo tempore manet similis, sed de facili ingrossatur vel subtiliatur.	Then he explains why these colors quickly disappear and do not last long: it is because the cause of their appearance is "rapid,," i.e., quickly passes — for air does not maintain a given state very long, and becomes thick or fine very easily.
Deinde cum dicit: hiatus autem etc., assignat causam hiatus et voraginis. Et dicit quod cum lumen quod apparet in aere, discontinuatur ex aliquo obscuro et nigro, quod scilicet est propter aliquem vaporem magis spissum, apparet quod sit aliqua profunditas et apertura in caelo. Et huius signum est quod, cum ille vapor qui interrumpit lumen, magis inspissatur, ex talibus hiatibus exeunt vel excidunt titiones ignei, quasi calido expulso a frigore vaporem inspissante. Sed quando ille vapor obscurus, discontinuans lumen, concretus et inspissatus fuerit magis, facit videri maiorem profunditatem, quia album superatur a nigro: cum autem fuerit e converso, tunc videtur solum hiatus vel apertura.	51. Then [50] he assigns the cause of "crevices" and "chasms" and says that when light visible in air is interrupted by something dark, due to thicker vapor than usual, depths and openings seem to exist in the heaven. A sign of this is that, when the vapor which interrupts the light becomes thicker still, fiery torches emerge or fall from these "crevices," as though something hot were ejected by the coldness which thickens the vapor. But when that dark vapor which interrupts the light becomes still more condensed and thick, it causes a greater depth to appear, because the white is overcome by black; when the situation is just the opposite, then only a crevice or opening appears.
Patet ergo quod utraque apparitio, et colorum et hiatuum, habent similem causam, scilicet admixtionem adinvicem albi et nigri: sed color purpureus aut puniceus fit ex albo transparente per nigrum; hiatus autem et vorago ex nigro interrumpente album.	It is plain, therefore, that both apparitions, i.e., that of colors and that of crevices, have a like cause, namely, black and white mixing together: but the purple or crimson color results from white shining through something black, whereas the crevices and chasms result from something black screening the white.
Deinde cum dicit: omnino autem in nigro album etc., ostendit quod multa huiusmodi fiunt quae non apparent. Et dicit quod album coniunctum nigro multas facit differentias colorum; sicut apparet de flamma in fumo, quae facit diversos colores, secundum quod fumus fuerit densior vel rarior. Sed de die sol sua claritate prohibet huiusmodi colores apparere: de nocte vero non apparent nisi rubeus, quia alii colores, sicut viridis et alii obscuriores, sunt similes colori noctis, propter obscuritatem.	52. Then [51] he shows that many things of this sort occur but are not visible. And he says that white joined with black produces many varieties of color, as appears with flame in smoke, which produces various colors depending on whether the smoke is thick or fine. But by day the sun's brightness prevents these colors from being seen: at night, however, only red appears, because the other colors, such as green and other darker colors, are on account of their darkness like the color of night.
Ultimo epilogat praedeterminata. Et dicit quod praedictas causas oportet existimare de astris discurrentibus et ignitis, et de aliis huiusmodi apparitionibus, quaecumque festinas faciunt phantasias, idest quaecumque pertranseuntes videntur absque magna mora temporis.	Finally, he sums up what has been determined and says [52] that these must be taken as the causes of shooting-stars and fire-stars and like apparitions "that make hasty appearances," i.e., that are seen to pass by without lasting very long.

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Lecture 9 The opinions of others concerning comets
Chapter 6
περὶ δὲ τῶν κομητῶν καὶ τοῦ καλουμένου γάλακτος λέγωμεν, διαπορήσαντες πρὸς τὰ παρὰ τῶν ἄλλων εἰρημένα πρῶτον.	53 Let us go on to explain the nature of comets and the 'milky way', after a preliminary discussion of the views of others.
Ἀναξαγόρας μὲν οὖν καὶ Δημόκριτός φασιν εἶναι τοὺς κομήτας σύμφασιν τῶν πλανήτων ἀστέρων, ὅταν διὰ τὸ πλησίον ἐλθεῖν δόξωσι θιγγάνειν ἀλλήλων.	54 Anaxagoras and Democritus declare that comets are a conjunction of the planets approaching one another and so appearing to touch one another.
τῶν δ' Ἰταλικῶν τινες καλουμένων Πυθαγορείων ἕνα λέγουσιν αὐτὸν εἶναι τῶν πλανήτων ἀστέρων, ἀλλὰ διὰ πολλοῦ τε χρόνου τὴν φαντασίαν αὐτοῦ εἶναι καὶ τὴν ὑπερβολὴν ἐπὶ μικρόν, ὅπερ συμβαίνει καὶ περὶ τὸν τοῦ Ἑρμοῦ ἀστέρα διὰ γὰρ τὸ μικρὸν ἐπαναβαίνειν πολλὰς ἐκλείπει φάσεις, ὥστε διὰ χρόνου φαίνεσθαι πολλοῦ.	55 Some of the Italians called Pythagoreans say that the comet is one of the planets, but that it appears at great intervals of time and only rises a little above the horizon. This is the case with Mercury too; because it only rises a little above the horizon it often fails to be seen and consequently appears at great intervals of time.
παραπλησίως δὲ τούτοις καὶ οἱ περὶ Ἱπποκράτην τὸν Χῖον καὶ τὸν μαθητὴν αὐτοῦ (343a.) Αἰσχύλον ἀπεφήναντο, πλὴν τήν γε κόμην οὐκ ἐξ αὑτοῦ φασιν ἔχειν, ἀλλὰ πλανώμενον διὰ τὸν τόπον ἐνίοτε λαμβάνειν ἀνακλωμένης τῆς ἡμετέρας ὄψεως ἀπὸ τῆς ἑλκομένης ὑγρότητος ὑπ' αὐτοῦ πρὸς τὸν ἥλιον. διὰ δὲ τὸ ὑπολείπεσθαι βραδύτατα τῷ χρόνῳ διὰ πλείστου χρόνου φαίνεσθαι τῶν ἄλλων ἄστρων, ὡς ὅταν ἐκ ταὐτοῦ φανῇ ὑπολελειμμένον ὅλον τὸν ἑαυτοῦ κύκλον ὑπολείπεσθαι δ' αὐτὸν καὶ πρὸς ἄρκτον καὶ πρὸς νότον. ἐν μὲν οὖν τῷ μεταξὺ τόπῳ τῶν τροπικῶν οὐχ ἕλκειν τὸ ὕδωρ πρὸς ἑαυτὸν διὰ τὸ κεκαῦσθαι ὑπὸ τῆς τοῦ ἡλίου φορᾶς πρὸς δὲ νότον ὅταν φέρηται, δαψίλειαν μὲν ἔχειν τῆς τοιαύτης νοτίδος, ἀλλὰ διὰ τὸ μικρὸν εἶναι τὸ ὑπὲρ τῆς γῆς τμῆμα τοῦ κύκλου, τὸ δὲ κάτω πολλαπλάσιον, οὐ δύνασθαι τὴν ὄψιν τῶν ἀνθρώπων φέρεσθαι κλωμένην πρὸς τὸν ἥλιον οὔτε τῷ τροπικῷ τόπῳ πλησιάζοντος οὔτ' ἐπὶ θεριναῖς τροπαῖς ὄντος τοῦ ἡλίου διόπερ ἐν τούτοις μὲν τοῖς τόποις οὐ γίγνεσθαι κομήτην αὐτόν ὅταν δὲ πρὸς βορέαν ὑπολειφθεὶς τύχῃ, λαμβάνειν κόμην διὰ τὸ μεγάλην εἶναι τὴν περιφέρειαν τὴν ἄνωθεν τοῦ ὁρίζοντος, τὸ δὲ κάτω μέρος τοῦ κύκλου μικρόν ῥᾳδίως γὰρ τὴν ὄψιν τῶν ἀνθρώπων ἀφικνεῖσθαι τότε πρὸς τὸν ἥλιον.	56 A view like theirs was also expressed by Hippocrates of Chios and his pupil Aeschylus. Only they say that the tail does not belong to the comet iself, but is occasionally assumed by it on its course in certain situations, when our sight is reflected to the sun from the moisture attracted by the comet. It appears at greater intervals than the other stars because it is slowest to get clear of the sun and has been left behind by the sun to the extent of the whole of its circle before it reappears at the same point. It gets clear of the sun both towards the north and towards the south. In the space between the tropics it does not draw water to itself because that region is dried up by the sun on its course. When it moves towards the south it has no lack of the necessary moisture, but because the segment of its circle which is above the horizon is small, and that below it many times as large, it is impossible for the sun to be reflected to our sight, either when it approaches the southern tropic, or at the summer solstice. Hence in these regions it does not develop a tail at all. But when it is visible in the north it assumes a tail because the arc above the horizon is large and that below it small. For under these circumstances there is nothing to prevent our vision from being reflected to the sun.

Postquam philosophus determinavit de stellis cadentibus et similibus, hic determinat de cometis.	53. After determining concerning falling stars and the like, the Philosopher now determines about comets.
Et primo dicit de quo est intentio: dicens quod nunc dicendum est de cometis et lacteo circulo, hoc ordine servato circa utrumque, ut primo inferamus dubitationes, idest obiectiones, ad ea quae dicta sunt ab aliis, et postea determinemus quod nobis videtur. Secundo ibi: Anaxagoras quidem igitur etc., prosequitur propositum ordine praemisso.	First, he states his intention [53] and says that we must speak now of comets and the milky circle, observing with respect to each the following order: first, we shall present the "doubts," i.e., the objections to what others have said, and then we shall state what we think. Secondly [54], he pursues his proposition in the order stated.
Unde primo ponit opiniones aliorum de cometis; secundo determinat de eis secundum opinionem suam, ibi: quoniam autem de immanifestis et cetera.	First, therefore, he presents what others thought of comets; Secondly, he determines about them according to his own opinion (L. 11).
Prima dividitur in duas:	The first is divided into two parts:
in prima ponit opiniones; in secunda improbat eas, ibi: omnibus autem et cetera.	In the first he presents the opinions; In the second he disproves them (L. 10).
Prima dividitur in tres, secundum tres opiniones quas ponit.	The first is divided into three parts according to the three opinions he presents.
Primo ergo ponit opinionem Anaxagorae et Democriti, qui dixerunt cometas esse symphasim, idest coapparitionem, stellarum errantium. Quae sunt quinque, scilicet Saturnus, Iupiter, Mars, Venus et Mercurius; quarum aliquae, cum appropinquant adinvicem, videntur se tangere; et ita videtur una stella, et apparet ei coma, propter augmentum luminis.	54. First therefore [54], he gives the opinion of Anaxagoras and Democritus who said that comets are "symphases," i.e., co-appearances of [planets] the wandering stars. These are five in number (namely, Saturn, Jupiter, Mars, Venus and Mercury), some of which, as they approach one another seem to touch, and there seems to be one star, and "flowing hair" appears [the coma, hence "comet"], due to the increase of light.
Secundam opinionem ponit ibi: Italicorum autem et cetera. Et fuit quorundam Pythagoricorum in Italia commorantium, qui dixerunt cometam esse unam de stellis errantibus; sed non esse phantasiam, idest visionem, eius, nisi post multum tempus, propter hoc quod excedit, idest recedit a sole, modicum; sicut et accidit circa stellam Mercurii, quae quia modicum digreditur, idest elongatur a sole, frequenter non apparet, ita quod post longum tempus appareat, cum diu non apparuit.	55. He presents the second opinion [55], which was that of certain Pythagoreans living in Italy who said that a comet is one of the wandering stars [planets], but that the "phantasy," i.e., vision, of it occurs only after a long lapse of time, because it "exceeds," i.e., departs from the sun only slightly — as is the case with the star Mercury, which, because it only slightly "digresses from," i.e., moves away from, the sun, frequently does not appear, appearing only after a long time, having for a long time not appeared.
Tertiam opinionem ponit ibi: similiter his etc.: quae fuit quorundam sequentium Hippocratem et Aeschylum eius discipulum. Quae quidem opinio in hoc similis est secundae, quod posuit stellam cometam esse unam de errantibus: sed in hoc differt ab ea, quod secunda opinio posuit quod illa stella erratica habet comam ex se; sed ista tertia opinio ponit quod non habet comam ex seipsa, sed cum sit errans, ex loco aliquando accipit comam. Quia dicebant quod ab ipsa stella attrahitur quidam humor; et cum ponerent quod visus fieret extramittendo, posuerunt quod radius visualis pertingens ad illum humorem attractum ab ea, repercutitur usque ad solem; et sic ille vapor attractus est quasi quoddam speculum igneum solis (nam repercussio est causa quod aliquid in speculo videatur); et ita dicunt fieri comam.	56. He presents the third opinion [56], which was that of certain followers of Hippocrates, and of Aeschylus, his disciple. This opinion is similar to the second in supposing that a comet is one of the wandering stars; it differs in that the second opinion held the wandering star had a tail [ coma ] of itself, whereas this third opinion holds that it does not have a tail of itself, but, since it is wandering, sometimes acquires a tail by its position. According to this opinion a certain moisture is attracted by the star, and, since they assume that vision occurs by a beholder emitting visual rays, they posited that a visual ray reaches that moisture attracted by the star and is then reflected toward the sun. In this way the attracted vapor acts as a certain fiery mirror for the sun (for things are visible in a mirror because of reflection); and they say that it is thus that the tail is formed.
Assignat autem consequenter causam de tempore apparitionis. Et dicit quod stella cometa apparet post plurimum tempus aliorum astrorum, idest magis occultatur quam aliquae aliae stellae, quia tardissime discedit a sole secundum tempus, videlicet cum peregerit totum suum circulum. Quod appellat subdeficere: dicuntur enim stellae errantes subdeficere respectu primi motus; vel quia moventur motu contrario, et sic videntur secundum proprium motum posteriorari; vel quia, sicut quidam dixerunt, tardius moventur quam primum caelum, quod revolvit omnia motu diurno. Sic autem dicebant quod stella cometa subdeficit a sole, totum suum circulum peragendo: et ideo, cum redierit ad illum terminum ex quo incoepit discedere, iterum apparet, quousque iterum coniungatur soli. Et dicebant etiam quod ista stella in suo motu recedit a sole, non tantum secundum longitudinem, sed etiam secundum latitudinem, declinans ad arctum et Austrum, idest ad Septentrionem et meridiem.	57. Then he assigns the cause regulating the time of its appearance and says that a comet star "appears at greater intervals than the other stars," i.e., is rendered invisible longer than the other stars, because time-wise it is very slow in getting clear of the sun, i.e., only when it has completed its entire cycle. He calls this "being left behind": for the wandering stars are said to be "left behind" with respect to the first motion, either because they are moved in a contrary direction and thus seem to retreat by their own motion, or because, as some say, they are moved more slowly than the first heaven which in its diurnal motion revolves everything else. So they said that a comet star is left behind by the sun to the extent of the whole of its orbit; and therefore, when it returns to the point where it first began to recede, it appears once more and remains in view until it again gets in conjunction with the sun. They also said that this star moves away from the sun not only according to longitude, but also according to latitude, declining to the north and south winds, i.e., to the north and to the south.
Assignat etiam consequenter causam circa locum apparitionis huius stellae. Et dicit quod haec stella non apparet in medio duorum tropicorum, scilicet cancri et Capricorni: quia per illam partem caeli movetur sol et consumit humiditatem, unde in ea parte caeli non potest praedicta stella attrahere aquam. Sed cum declinat ad Austrum, recedens a via solis, invenit copiam ibi talis humiditatis, eo quod non est consumpta a sole. Sed propter obliquitatem horizontis, nobis qui habitamus in parte Septentrionali, pars circuli paralleli quae est supra terram est parva, quae autem est sub terra est maior: et sic sol, qui de nocte, cum videtur cometa, est sub terra, tantum distat ab humore attracto a stella, quod non potest visus hominum repercuti ab humore ad solem; neque si sol sit propinquus tropico, scilicet Capricorno, neque si sit in aestivis versionibus, idest in tropico aestivo, qui est cancer. Ubicumque enim fuerit sol sub terra, erit maior distantia eius ad vaporem contractum quam sit conveniens repercussioni, vel ex circulo, vel ex latitudine zodiaci. Sed quando stella illa relinquitur a sole versus Boream, idest ad Septentrionalem partem, tunc potest recipere comam: quia ibi est multum de humiditate, et peripheria circuli quae est super horizontem est ibi magna, et quae est subtus est parva, et sic de facili visus hominum refractus potest pertingere ad solem.	58. He also assigns the cause regarding the place of this star's appearance. And he says that this star does not appear in between the two tropics, namely, of Cancer and Capricorn; for the sun travels through that portion of the heaven and consumes the moisture, so that in that portion of the heaven this star cannot attract any water. But when it shifts to the south, receding from the sun's course, it finds there an abundance of moisture, because it had not been consumed by the sun. But because of the obliquity of the horizon, for us who live in the north the part of its parallel circle which is above the earth is small, whereas the part below is larger; consequently, the sun which, at night, when comets are visible, is under the earth, is so far from the moisture attracted by the star that a man's vision cannot be reflected from the moisture to the sun — whether the sun is near the "tropic," namely, that of Capricorn, or whether it is in the "summer turnings," i.e., in the summer tropic, which is that of Cancer. For no matter where the sun is under the earth, its distance from the contracted vapor is too great for reflection, either from the circle or from the latitude of the zodiac. But when that star is left behind by the sun toward the "boreal" [north wind], i.e., the north, then it can acquire a tail — because there is there much moisture, and the circumference of its circle above the horizon is large there, whereas the part below is small. Consequently it is easy for man's reflected vision to reach the sun.

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Lecture 10 Refutation of these opinions
Chapter 6 cont.
πᾶσιν δὲ τούτοις τὰ μὲν κοινῇ συμπίπτει λέγειν ἀδύνατα, τὰ δὲ χωρίς.	57 These views involve impossibilities, some of which are common to all of them, while others are peculiar to some only.
πρῶτον μὲν οὖν τοῖς λέγουσιν ὅτι τῶν πλανωμένων ἐστὶν εἷς ἀστέρων ὁ κομήτης οἱ γὰρ πλανώμενοι πάντες ἐν τῷ κύκλῳ ὑπολείπονται τῷ τῶν ζῳδίων, κομῆται δὲ πολλοὶ ἑωραμένοι εἰσὶν ἔξω τοῦ κύκλου. εἶτα καὶ πλείους ἑνὸς ἅμα γεγένηνται πολλάκις.	58 This is the case, first, with those who say that the comet is one of the planets. For all the planets appear in the circle of the zodiac, whereas many comets have been seen outside that circle. Again more comets than one have often appeared simultaneously.
πρὸς δὲ τούτοις, εἰ διὰ τὴν ἀνάκλασιν τὴν κόμην ἴσχουσι, καθάπερ φησὶν Αἰσχύλος καὶ Ἱπποκράτης, ἔδει ποτὲ φαίνεσθαι καὶ ἄνευ κόμης τὸν ἀστέρα τοῦτον, ἐπειδήπερ ὑπολείπεται μὲν καὶ εἰς ἄλλους τόπους, τὴν δὲ κόμην ἴσχει οὐ πανταχοῦ νῦν δ' οὐδεὶς ὦπται παρὰ τοὺς πέντε ἀστέρας οὗτοι δὲ πολλάκις ἅμα πάντες μετέωροι φαίνονται ὑπὲρ τοῦ ὁρίζοντος. καὶ φανερῶν δὲ ὄντων αὐτῶν ἁπάντων καὶ μὴ φαινομένων πάντων, ἀλλ' ἐνίων ὄντων πρὸς τῷ ἡλίῳ, οὐδὲν ἧττον κομῆται φαίνονται γιγνόμενοι πολλάκις.	59 Besides, if their tail is due to reflection, as Aeschylus and Hippocrates say, this planet ought sometimes to be visible without a tail since, as they it does not possess a tail in every place in which it appears. But, as a matter of fact, no planet has been observed besides the five. And all of them are often visible above the horizon together at the same time. Further, comets are often found to appear, as well when all the planets are visible as when some are not, but are obscured by the neighbourhood of the sun.
ἀλλὰ μὴν οὐδὲ τοῦτο ἀληθές, ὡς ἐν τῷ πρὸς ἄρκτον τόπῳ γίγνεται κομήτης μόνον, ἅμα καὶ τοῦ ἡλίου (343b.) ὄντος περὶ θερινὰς τροπάς ὅ τε γὰρ μέγας κομήτης ὁ γενόμενος περὶ τὸν ἐν Ἀχαΐᾳ σεισμὸν καὶ τὴν τοῦ κύματος ἔφοδον ἀπὸ δυσμῶν τῶν ἰσημερινῶν ἀνέσχεν, καὶ πρὸς νότον ἤδη πολλοὶ γεγόνασιν.	60 Moreover the statement that a comet only appears in the north, with the sun at the summer solstice, is not true either. The great comet which appeared at the time of the earthquake in Achaea and the tidal wave rose due west; and many have been known to appear in the south.
ἐπὶ δ' ἄρχοντος Ἀθήνησιν Εὐκλέους τοῦ Μόλωνος ἐγένετο κομήτης ἀστὴρ πρὸς ἄρκτον μηνὸς Γαμηλιῶνος περὶ τροπὰς ὄντος τοῦ ἡλίου χειμερινάς καίτοι τοσοῦτον ἀνακλασθῆναι καὶ αὐτοὶ τῶν ἀδυνάτων εἶναί φασι.	61 Again in the archonship of Euclees, son of Molon, at Athens there appeared a comet in the north in the month Gamelion, the sun being about the winter solstice. Yet they themselves admit that reflection over so great a space is an impossibility.
κοινὸν δὲ καὶ τούτοις καὶ τοῖς τὴν σύναψιν λέγουσιν πρῶτον μὲν ὅτι καὶ τῶν ἀπλανῶν λαμβάνουσι κόμην τινές. καὶ τοῦτ' οὐ μόνον Αἰγυπτίοις πιστεῦσαι δεῖ, καίτοι κἀκεῖνοί φασιν, ἀλλὰ καὶ ἡμεῖς ἐφεωράκαμεν τῶν γὰρ ἐν τῷ ἰσχίῳ τοῦ κυνὸς ἀστήρ τις ἔσχε κόμην, ἀμαυρὰν μέντοι ἀτενίζουσιν μὲν γὰρ εἰς αὐτὸν ἀμυδρὸν ἐγίγνετο τὸ φέγγος, παραβλέπουσι δ' ἠρέμα τὴν ὄψιν πλέον.	62 An objection that tells equally against those who hold this theory and those who say that comets are a coalescence of the planets is, first, the fact that some of the fixed stars too get a tail. For this we must not only accept the authority of the Egyptians who assert it, but we have ourselves observed the fact. For a star in the thigh of the Dog had a tail, though a faint one. If you fixed your sight on it its light was dim, but if you just glanced at it, it appeared brighter.
πρὸς δὲ τούτοις ἅπαντες οἱ καθ' ἡμᾶς ὠμμένοι ἄνευ δύσεως ἠφανίσθησαν ἐν τῷ ὑπὲρ τοῦ ὁρίζοντος τόπῳ ἀπομαρανθέντες κατὰ μικρὸν οὕτως, ὥστε μήτε ἑνὸς ἀστέρος ὑπολειφθῆναι σῶμα μήτε πλειόνων, ἐπεὶ καὶ ὁ μέγας ἀστὴρ περὶ οὗ πρότερον ἐμνήσθημεν ἐφάνη μὲν χειμῶνος ἐν πάγοις καὶ αἰθρίαις ἀφ' ἑσπέρας, ἐπὶ Ἀστείου ἄρχοντος, καὶ τῇ μὲν πρώτῃ οὐκ ὤφθη ὡς προδεδυκὼς τοῦ ἡλίου, τῇ δ' ὑστεραίᾳ ὤφθη ὅσον ἐνδέχεται γὰρ ἐλάχιστον ὑπελείφθη, καὶ εὐθὺς ἔδυ τὸ δὲ φέγγος ἀπέτεινε μέχρι τοῦ τρίτου μέρους τοῦ οὐρανοῦ οἷον ἅλμα διὸ καὶ ἐκλήθη ὁδός. ἐπανῆλθε δὲ μέχρι τῆς ζώνης τοῦ Ὠρίωνος, καὶ ἐνταυθοῖ διελύθη. καίτοι Δημόκριτός γε προσπεφιλονείκηκεν τῇ δόξῃ τῇ αὑτοῦ φησὶ γὰρ ὦφθαι διαλυομένων τῶν κομητῶν ἀστέρας τινάς. τοῦτο δὲ οὐχ ὁτὲ μὲν ἔδει γίγνεσθαι ὁτὲ δὲ οὔ, ἀλλ' ἀεί. πρὸς δὲ τούτοις καὶ οἱ Αἰγύπτιοί φασι καὶ τῶν πλανήτων καὶ πρὸς αὑτοὺς καὶ πρὸς τοὺς ἀπλανεῖς γίγνεσθαι συνόδους, καὶ αὐτοὶ ἑωράκαμεν τὸν ἀστέρα τὸν τοῦ Διὸς τῶν ἐν τοῖς διδύμοις συνελθόντα τινὶ ἤδη καὶ ἀφανίσαντα, ἀλλ' οὐ κομήτην γενόμενον.	63 Besides, all the comets that have been seen in our day have vanished without setting, gradually fading away above the horizon; and they have not left behind them either one or more stars. For instance the great comet we mentioned before appeared to the west in winter in frosty weather when the sky was clear, in the archonship of Asteius. On the first day it set before the sun and was then not seen. On the next day it was seen, being ever so little behind the sun and immediately setting. But its light extended over a third part of the sky like a leap, so that people called it a 'path'. This comet receded as far as Orion's belt and there dissolved. Democritus however, insists upon the truth of his view and affirms that certain stars have been seen when comets dissolve. But on his theory this ought not to occur occasionally but always.
ἔτι δὲ καὶ ἐκ τοῦ λόγου φανερόν οἱ γὰρ ἀστέρες κἂν εἰ μείζους καὶ ἐλάττους φαίνονται, ἀλλ' ὅμως ἀδιαίρετοί γε καθ' ἑαυτοὺς εἶναι δοκοῦσιν.	64 Besides, the Egyptians affirm that conjunctions of the planets with one another, and with the fixed stars, take place, and we have ourselves observed Jupiter coinciding with one of the stars in the Twins and hiding it, and yet no comet was formed.
ὥσπερ οὖν καὶ εἰ ἦσαν ἀδιαίρετοι, ἁψάμενοι οὐδὲν ἂν ἐποίησαν μέγεθος μεῖζον, οὕτως καὶ ἐπειδὴ οὐκ εἰσὶν μὲν φαίνονται δὲ (344a.) ἀδιαίρετοι, καὶ συνελθόντες οὐδὲν φανοῦνται μείζους τὸ μέγεθος ὄντες.	65 Further, we can also give a rational proof of our point. It is true that some stars seem to be bigger than others, yet each one by itself looks indivisible. Consequently, just as, if they really had been indivisible, their conjunction could not have created any greater magnitude, so now that they are not in fact indivisible but look as if they were, their conjunction will not make them look any bigger.
ὅτι μὲν οὖν αἱ λεγόμεναι περὶ αὐτῶν αἰτίαι ψευδεῖς οὖσαι τυγχάνουσιν, εἰ μὴ διὰ πλειόνων, ἀλλὰ καὶ διὰ τούτων ἱκανῶς δῆλόν ἐστιν.	66 Enough has been said, without further argument, to show that the causes brought forward to explain comets are false.

Positis opinionibus, hic improbat eas.	59. Having presented the opinions, he now disproves them.
Et primo ponit modum improbandi: et dicit quod quaedam intendit inducere quae sunt communiter contra omnes praedictas opiniones, quaedam vero quae sunt contra aliquam earum specialiter tantum.	First, he declares how they are to be disproved [57] and says that he intends to present certain facts against all the opinions as a group, and certain facts against one or other of them in particular. Secondly, he disputes against the opinions presented.
Secundo ibi: primo quidem igitur etc., disputat contra positas opiniones: et primo contra secundam, quae fuit Pythagoricorum; secundo contra tertiam, quae fuit Hippocratis, ibi: adhuc autem si propter etc.; tertio contra primam, quae fuit Democriti et Anaxagorae, ibi: commune autem et his et cetera.	First, against the second one, which was that of the Pythagoreans; Secondly, against the third, which was Hippocrates', at 61; Thirdly, against the first, which was that of Democritus and Anaxagoras, 64b.
Circa primum ponit duas rationes: quarum prima talis est. Omnes stellae erraticae subdeficiunt, idest moventur quasi subdeficiendo, sicut expositum est, in circulo animalium qui dicitur zodiacus; sed multi cometae visi sunt extra hunc circulum; ergo non omnes cometae sunt stellae erraticae.	60. As to the first [58] he gives two arguments: the first of which is that all the wandering stars are "left behind," i.e., move as though being left behind, as already explained, in the "circle of animals called the "Zodiac"; on the other hand, many comets are found outside this circle. Therefore, not all comets are wandering stars.
Secunda ratio talis est. Saepe visi sunt cometae plures uno simul facti: non igitur cometa est una stellarum errantium. Harum rationum prima est communis contra has opiniones: secunda est propria contra secundam et tertiam opinionem.	The second argument is this: more comets than one have often been seen together; hence a comet is not one of the wandering stars. The first of these arguments is against these opinions together; the second is specifically against the second and third opinions.
Deinde cum dicit: adhuc autem si propter etc., improbat opinionem Hippocratis per tres rationes. Circa quarum primam dicit quod, si aliquis planetarum propter refractionem visus habet comam, sicut dixit Hippocrates, oporteret quod aliquando haec stella erratica appareret sine coma. Et hoc ideo, quia non ubique habet comam, ut dictum est, sed solum cum est extra tropicos, declinans ad Septentrionem: manifestum est autem quod etiam in aliis locis subdeficit, quasi discedens a sole; et ita oportet quod aliquando videatur sine coma. Sed nulla stella visa est sine coma errans praeter quinque stellas supra nominatas; quae quandoque omnes apparent simul elevatae super horizontem, et omnibus eis existentibus super horizontem, vel etiam quibusdam earum apparentibus super horizontem et quibusdam existentibus cum sole, nihilominus apparent cometae. Et sic manifestum est quod non semper cometa est una quinque stellarum errantium. Et nulla est alia sine coma praeter has. Ergo cometa non est stella errans, quandoque sine coma apparens: quod oporteret si comam ex seipso non haberet, sed ex aliquo loco determinato, ut ipsi dicunt.	61. Then [59] he disproves the opinion of Hippocrates with three arguments. As to the first of these he says that if a planet has a tail because of the reflection of the sight, as Hippocrates said, then it would have occasionally to appear without a tail. This is because it does not everywhere have a tail, as was said, but only when it is outside the tropics, receding to the north — for it is plain that it "falls behind" in other places as though receding from the sun; consequently it must sometimes appear without a tail. But no star is seen wandering without a tail other than the above-mentioned five. But occasionally all five are visible above the horizon at the same time; and when all are above the horizon, or some appear above and some are with the sun, comets nevertheless appear. Hence it is plain that a comet is not always one of the five wandering stars. And there is no other without a tail than these [five]. Therefore a comet is not a wandering star, which on occasion appears with a tail — which would have to be the case, if it did not possess a tail of itself but from being in some determined place, as they claim.
Secundam rationem ponit ibi: at vero neque hoc verum et cetera. Et dicit quod non est verum quod cometa fiat solum in loco qui declinat ad Septentrionem, hoc simul observato quod sol tunc sit circa tropicos aestivales, quasi propinquius stellae. Quia magnus cometes qui factus est eo tempore quo fuit factus terraemotus magnus in Achaia et supergressio fluctuum, ortus fuit ab occasibus aequinoctialibus: et ita manifestum est quod fuit infra tropicos. Et iam etiam multi facti sunt ad Austrum. Falsum est ergo quod dicunt, quod fiat tantum ad Septentrionem.	62. He gives the second argument [60] and says that it is not true to say that a comet occurs only in the region toward the north with the additional observation of the sun at the summer tropics [i.e., summer solstice], as though nearer to the comet. For the great comet which appeared at the time of the great earthquake and tidal wave in Achaia arose from the western equator; so it is plain that it occurred within the "tropics." Moreover, many have appeared in the south. It is therefore false to say that they occur only toward the north.
Tertiam rationem ponit ibi: sub principe autem et cetera. Et dicit quod tempore cuiusdam principis Atheniensium, facta fuit stella cometa, sole existente circa tropicos hiemales, idest circa Capricornum, et hoc mense Gamelione, idest Decembri vel Ianuario. Et hoc videtur esse impossibile, sicut etiam ipsi dicunt, quod fiat tanta refractio visus nostri ad solem, propter distantiam eius quae est tunc temporis de nocte ad solem, et propter magnitudinem decisionis circuli qui est sub horizonte. Falsum est ergo quod dicunt, quod non appareat cometa nisi sole existente circa tropicum aestivalem.	63. He gives a third argument [61] and says that in the time of a certain Athenian ruler, a comet star was formed when the sun was near the winter tropics [solstice], i.e., near Capricorn and this was in the month of "Gamelion," i.e., December or January. Now as they themselves admit, it seems impossible for such a long reflection from our vision to the sun to occur, considering the distance to the sun then prevailing at night and considering the size of the section of the circle below the horizon. Therefore, their claim that a comet does not appear unless the sun is near the summer tropic [solstice] is false.
Deinde cum dicit: commune autem et his etc., improbat primam opinionem per quatuor rationes. Quarum prima est contra omnes praedictas opiniones dicentes cometas esse stellas erraticas: quia etiam quaedam stellarum non errantium accipiunt comam. Et hoc non solum oportet credere Aegyptiis studentibus in mathematicis, qui hoc dicunt; sed ipse Aristoteles dicit se hoc vidisse, quod una stellarum quae est in figuratione canis, apud femur eius, comam habuit, sed debilem: quod patuit quia, quando aliquis fortiter intendebat in ipsam, debilitabatur lumen comae; sed quando aliquis iaciebat visum in stellam non nimis intense et remissius, plus apparebat lumen comae.	64. Then [62] he disproves the first opinion with four arguments. The first of these is against all the aforesaid opinions that claim the comets are wandering stars — for even certain stars that are not wandering receive a tail. And this is to be believed not only on the authority of certain Egyptians devoted to mathematics, but Aristotle himself says that he saw one of the stars in the constellation of the Dog, in the thigh, to be exact, with a tail, although it was faint: this was evidenced by the fact that when you gazed at it intently, the light of the tail grew dim, but when one glanced at the star not too intensely but more moderately, more of the tail's light appeared.
Secundam rationem ponit ibi: adhuc autem omnes et cetera. Et dicit quod omnes cometae qui suo tempore fuerunt visi, disparuerunt in loco super horizontem sine occasu, idest sine appropinquatione ad solem. Tunc enim dicitur occasus stellarum, quando intrant sub radiis solis: sed cometae apparentes suo tempore, disparuerunt sine hoc quod appropinquarent ad solem, adhuc super horizontem existentes longe a sole. Et disparuerunt quasi paulatim consumpti, ita quod non derelinqueretur neque corpus unius stellae neque plurium. Quia magna stella de qua supra diximus quod fuit tempore terraemotus in Achaia, apparuit tempore hiemis in vespere, existente gelu et serenitate, sub Astio principe Atheniensium; et primo die non apparuit ipsa stella, sed solum coma eius, quasi occidens ante solem; secundo autem die apparuit quantum possibile fuit, quia per modicum tempus remansit post solem et mox occubuit; sed lumen cometa extendit usque ad tertiam partem caeli, quasi simul et non paulatim crescens in lumine, ita ut ille ascensus luminis vocatus fuerit via cometae; et ascendit etiam, retrocedens a sole, usque ad quasdam stellas quae vocantur zona Orionis, et ibi fuit dissoluta, non appropinquando ad solem, sed magis ac magis discedendo ab eo.	65. In the second argument [63] he says that all the comets that were seen in his time disappeared in a region above the horizon "without setting," i.e., without approaching the sun. For stars are said to "set" when they enter into the sun's rays; but the comets of his time disappeared without approaching the sun, still being above the horizon far from the sun. And they disappeared as if gradually wasting away without leaving behind the body of one star or of several. For the great star previously described, which was at the time of the earthquake in Achaia, in the Athenian archonship of Astius, appeared in winter during the evening when it was frosty and clear: on the first day, not the star, but only its tail, appeared, as though setting before the sun; but on the second day it was as visible as conditions permitted, because for a short time it remained behind the sun and then immediately set; but the light of that comet spread over a third part of the heaven which burst into light not gradually but all at once, so that the upward ascent of the light was called the comet's path; it did indeed ascend, receding from the sun toward the stars called "Orion's belt," where it was dissolved, not by approaching the sun, but by receding farther and farther from it.
Haec etiam ratio est contra omnes opiniones praedictas, quae dicunt cometam esse unam vel plures stellarum errantium. Et sic patet per hanc rationem quod illud quod Democritus dixit ad confirmandam suam opinionem, non fuit sufficiens. Dixit enim quod, dissolutis cometis, aliquando apparuerunt stellae quaedam remanentes: quod ideo est insufficiens, quia oportebat ipsum probare quod, non aliquando, sed semper remanserunt stellae dissolutis cometis; quod apparet esse falsum ex eo quod dictum est.	This is also an argument against all the foregoing opinions that say a comet is one or more of the wandering stars. Consequently, it is plain from this argument that what Democritus said in support of his opinion was insufficient. For he said that when comets dissolved, there sometimes appeared certain remaining stars. This is an insufficient explanation because it devolved on him to prove that stars always, and not just occasionally, remained when comets were dissolved — which has been seen to be false from what has been said.
Tertiam rationem ponit ibi: adhuc autem et Aegyptii etc.: quae talis est. Aegyptii dicunt quod fiunt coniunctiones stellarum errantium adinvicem et ad alias stellas fixas. Et dicit se vidisse stellam Iovis se supposuisse cuidam stellae quae est in geminis, ita quod fecit eam disparere. Sed tamen non fuit factus cometa: quod oporteret secundum opinionem Democriti et Anaxagorae.	66. He gives a third argument [64] which is this: Egyptians claim that the conjunctions of the planets with one another and with certain fixed stars take place. And he says that he himself saw Jupiter conjoin with a star in Gemini and make it invisible. Yet no comet was formed, as should have according to the opinion of Democritus and Anaxagoras.
Quartam rationem ponit ibi: adhuc autem et ex ratione etc.: quae talis est. Quamvis stellarum quaedam videantur esse maiores et quaedam minores adinvicem comparatae, tamen unaquaeque secundum se considerata videtur quasi punctalis et indivisibilis. Sed si essent vere indivisibiles, se invicem tangentes non facerent maiorem magnitudinem, ut probatum est in VI Physic. Ergo quando videntur indivisibiles licet non sint, quando coniunguntur adinvicem, non debent videri maiores secundum apparentem magnitudinem. Et ita ex contactu stellarum non debet videri coma, quasi propter augmentum luminis. Hae autem duae ultimae rationes sunt proprie contra opinionem Democriti. Ultimo autem recolligit illud quod dictum est: et patet in littera.	67. The fourth argument [65] is this: Although some stars seem to be larger and some smaller when compared to one another, yet each considered by itself appears to be as though a point and indivisible. But if they were in very truth indivisible, they could not produce a larger magnitude by merely touching one another, as was proved in Physics VI. Therefore, when they seem to be indivisibles, although they are not, they should not, when in conjunction, seem larger as far as their apparent size is concerned. Consequently, from the conjunction of stars a tail should not be visible as though produced by an increase of light. (These last two arguments are properly against Democritus' opinion). Finally, he summarizes what has been said — as is had in text [66].

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Lecture 11 The cause, time and place of the appearance of comets according to Aristotle
Chapter 7
ἐπεὶ δὲ περὶ τῶν ἀφανῶν τῇ αἰσθήσει νομίζομεν ἱκανῶς ἀποδεδεῖχθαι κατὰ τὸν λόγον, ἐὰν εἰς τὸ δυνατὸν ἀναγάγωμεν,	67 We consider a satisfactory explanation of phenomena inaccessible to observation to have been given when our account of them is free from impossibilities.
ἔκ τε τῶν νῦν φαινομένων ὑπολάβοι τις ἂν ὧδε περὶ τούτων μάλιστα συμβαίνειν ὑπόκειται γὰρ ἡμῖν τοῦ κόσμου τοῦ περὶ τὴν γῆν, ὅσον ὑπὸ τὴν ἐγκύκλιόν ἐστιν φοράν, εἶναι τὸ πρῶτον μέρος ἀναθυμίασιν ξηρὰν καὶ θερμήν αὕτη δὲ αὐτή τε καὶ τοῦ συνεχοῦς ὑπ' αὐτὴν ἀέρος ἐπὶ πολὺ συμπεριάγεται περὶ τὴν γῆν ὑπὸ τῆς φορᾶς καὶ τῆς κινήσεως τῆς κύκλῳ φερομένη δὲ καὶ κινουμένη τοῦτον τὸν τρόπον, ᾗ ἂν τύχῃ εὔκρατος οὖσα, πολλάκις ἐκπυροῦται διό φαμεν γίγνεσθαι καὶ τὰς τῶν σποράδων ἀστέρων διαδρομάς.	68 The observations before us suggest the following account of the phenomena we are now considering. We know that the dry and warm exhalation is the outermost part of the terrestrial world which falls below the circular motion. It, and a great part of the air that is continuous with it below, is carried round the earth by the motion of the circular revolution. In the course of this motion it often ignites wherever it may happen to be of the right consistency, and this we maintain to be the cause of the 'shooting' of scattered 'stars'.
ὅταν οὖν εἰς τὴν τοιαύτην πύκνωσιν ἐμπέσῃ διὰ τὴν ἄνωθεν κίνησιν ἀρχὴ πυρώδης, μήτε οὕτω πολλὴ λίαν ὥστε ταχὺ καὶ ἐπὶ πολὺ ἐκκαίειν, μήθ' οὕτως ἀσθενὴς ὥστε ἀποσβεσθῆναι ταχύ, ἀλλὰ πλείων καὶ ἐπὶ πολύ, ἅμα δὲ κάτωθεν συμπίπτῃ ἀναβαίνειν εὔκρατον ἀναθυμίασιν, ἀστὴρ τοῦτο γίγνεται κομήτης, ὅπως ἂν τὸ ἀναθυμιώμενον τύχῃ ἐσχηματισμένον ἐὰν μὲν γὰρ πάντῃ ὁμοίως, κομήτης, ἐὰν δ' ἐπὶ μῆκος, καλεῖται πωγωνίας.	69 We may say, then, that a comet is formed when the upper motion introduces into a gathering of this kind a fiery principle not of such excessive strength as to burn up much of the material quickly, nor so weak as soon to be extinguished, but stronger and capable of burning up much material, and when exhalation of the right consistency rises from below and meets it. The kind of comet varies according to the shape which the exhalation happens to take. If it is diffused equally on every side the star is said to be fringed, if it stretches out in one direction it is called bearded.
ὥσπερ δὲ ἡ τοιαύτη φορὰ ἀστέρος φορὰ δοκεῖ εἶναι, οὕτως καὶ ἡ μονὴ ἡ ὁμοία ἀστέρος μονὴ δοκεῖ εἶναι παραπλήσιον γὰρ τὸ γιγνόμενον οἷον εἴ τις εἰς ἀχύρων θημῶνα καὶ πλῆθος ὤσειε δαλὸν ἢ πυρὸς ἀρχὴν ἐμβάλοι μικράν φαίνεται γὰρ ὁμοία καὶ ἡ τῶν ἀστέρων διαδρομὴ τούτῳ ταχὺ γὰρ διὰ τὴν εὐφυΐαν τοῦ ὑπεκκαύματος διαδίδωσιν ἐπὶ μῆκος. εἰ δὴ τοῦτο μείνειε καὶ μὴ καταμαρανθείη διελθόν, ᾗ μάλιστα ἐπύκνωσε τὸ ὑπέκκαυμα, γένοιτ' ἂν ἀρχὴ τῆς φορᾶς ἡ τελευτὴ τῆς διαδρομῆς. τοιοῦτον ὁ κομήτης ἐστὶν ἀστήρ, ὥσπερ διαδρομὴ ἀστέρος, ἔχων ἐν ἑαυτῷ πέρας καὶ ἀρχήν. ὅταν μὲν οὖν ἐν αὐτῷ τῷ κάτω τόπῳ ἡ ἀρχὴ τῆς συστάσεως ᾖ, καθ' ἑαυτὸν φαίνεται κομήτης	70 We have seen that when a fiery principle of this kind moves we seem to have a shooting-star: similarly when it stands still we seem to have a star standing still. We may compare these phenomena to a heap or mass of chaff into which a torch is thrust, or a spark thrown. That is what a shooting-star is like. The fuel is so inflammable that the fire runs through it quickly in a line. Now if this fire were to persist instead of running through the fuel and perishing away, its course through the fuel would stop at the point where the latter was densest, and then the whole might begin to move. Such is a comet-like a shooting-star that contains its beginning and end in itself. When the matter begins to gather in the lower region independently the comet appears by itself.
ὅταν δ' ὑπὸ τῶν ἄστρων τινός, ἢ τῶν ἀπλανῶν ἢ τῶν πλανήτων, ὑπὸ τῆς κινήσεως συνιστῆται ἡ (344b.) ἀναθυμίασις, τότε κομήτης γίγνεται τούτων τις οὐ γὰρ πρὸς αὐτοῖς ἡ κόμη γίγνεται τοῖς ἄστροις, ἀλλ' ὥσπερ αἱ ἅλῳ περὶ τὸν ἥλιον φαίνονται καὶ τὴν σελήνην παρακολουθοῦσαι, καίπερ μεθισταμένων, ὅταν οὕτως ᾖ πεπυκνωμένος ὁ ἀὴρ ὥστε τοῦτο γίγνεσθαι τὸ πάθος ὑπὸ τὴν τοῦ ἡλίου πορείαν, οὕτω καὶ ἡ κόμη τοῖς ἄστροις οἷον ἅλως ἐστίν πλὴν ἡ μὲν γίγνεται δι' ἀνάκλασιν τοιαύτη τὴν χρόαν, ἐκεῖ δ' ἐπ' αὐτῶν τὸ χρῶμα φαινόμενόν ἐστιν.	71 But when the exhalation is constituted by one of the fixed stars or the planets, owing to their motion, one of them becomes a comet. The fringe is not close to the stars themselves. Just as haloes appear to follow the sun and the moon as they move, and encircle them, when the air is dense enough for them to form along under the sun's course, so too the fringe. It stands in the relation of a halo to the stars, except that the colour of the halo is due to reflection, whereas in the case of comets the colour is something that appears actually on them.
ὅταν μὲν οὖν κατ' ἀστέρα γένηται ἡ τοιαύτη σύγκρισις, τὴν αὐτὴν ἀνάγκη φαίνεσθαι φορὰν κινούμενον τὸν κομήτην ἥνπερ φέρεται ὁ ἀστήρ ὅταν δὲ συστῇ καθ' αὑτόν, τότε ὑπολειπόμενοι φαίνονται. τοιαύτη γὰρ ἡ φορὰ τοῦ κόσμου τοῦ περὶ τὴν γῆν. τοῦτο γὰρ μάλιστα μηνύει μὴ εἶναι ἀνάκλασίν τινα τὸν κομήτην, ὡς ἅλω ἐν ὑπεκκαύματι καθαρῷ πρὸς αὐτὸν τὸν ἀστέρα γιγνομένην, καὶ μὴ ὡς λέγουσιν οἱ περὶ Ἱπποκράτην, πρὸς τὸν ἥλιον, ὅτι καὶ καθ' αὑτὸν γίγνεται κομήτης πολλάκις καὶ πλεονάκις ἢ περὶ τῶν ὡρισμένων τινὰς ἀστέρων. περὶ μὲν οὖν τῆς ἅλω τὴν αἰτίαν ὕστερον ἐροῦμεν	72 Now when this matter gathers in relation to a star the comet necessarily appears to follow the same course as the star. But when the comet is formed independently it falls behind the motion of the universe, like the rest of the terrestrial world. It is this fact, that a comet often forms independently, indeed oftener than round one of the regular stars, that makes it impossible to maintain that a comet is a sort of reflection, not indeed, as Hippocrates and his school say, to the sun, but to the very star it is alleged to accompany—in fact, a kind of halo in the pure fuel of fire. As for the halo we shall explain its cause later.
περὶ δὲ τοῦ πυρώδη τὴν σύστασιν αὐτῶν εἶναι τεκμήριον χρὴ νομίζειν ὅτι σημαίνουσι γιγνόμενοι πλείους πνεύματα καὶ αὐχμούς δῆλον γὰρ ὅτι γίγνονται διὰ τὸ πολλὴν εἶναι τὴν τοιαύτην ἔκκρισιν, ὥστε ξηρότερον ἀναγκαῖον εἶναι τὸν ἀέρα, καὶ διακρίνεσθαι καὶ διαλύεσθαι τὸ διατμίζον ὑγρὸν ὑπὸ τοῦ πλήθους τῆς θερμῆς ἀναθυμιάσεως, ὥστε μὴ συνίστασθαι ῥᾳδίως εἰς ὕδωρ. σαφέστερον δ' ἐροῦμεν καὶ περὶ τούτου τοῦ πάθους, ὅταν καὶ περὶ πνευμάτων λέγειν ᾖ καιρός. ὅταν μὲν οὖν πυκνοὶ καὶ πλείους φαίνωνται, καθάπερ λέγομεν, ξηροὶ καὶ πνευματώδεις γίγνονται οἱ ἐνιαυτοὶ ἐπιδήλως ὅταν δὲ σπανιώτεροι καὶ ἀμαυρότεροι τὸ μέγεθος, ὁμοίως μὲν οὐ γίγνεται τὸ τοιοῦτον, οὐ μὴν ἀλλ' ὡς ἐπὶ τὸ πολὺ γίγνεταί τις ὑπερβολὴ πνεύματος ἢ κατὰ χρόνον ἢ κατὰ μέγεθος, ἐπεὶ καὶ ὅτε ὁ ἐν Αἰγὸς ποταμοῖς ἔπεσε λίθος ἐκ τοῦ ἀέρος, ὑπὸ πνεύματος ἀρθεὶς ἐξέπεσε μεθ' ἡμέραν ἔτυχε δὲ καὶ τότε κομήτης ἀστὴρ γενόμενος ἀφ' ἑσπέρας. καὶ περὶ τὸν μέγαν ἀστέρα τὸν κομήτην ξηρὸς ἦν ὁ χειμὼν καὶ βόρειος, καὶ τὸ κῦμα δι' ἐναντίωσιν ἐγένετο πνευμάτων ἐν μὲν γὰρ τῷ κόλπῳ (345a.) βορέας κατεῖχεν, ἔξω δὲ νότος ἔπνευσε μέγας. ἔτι δ' ἐπ' ἄρχοντος Νικομάχου ἐγένετο ὀλίγας ἡμέρας κομήτης περὶ τὸν ἰσημερινὸν κύκλον, οὐκ ἀφ' ἑσπέρας ποιησάμενος τὴν ἀνατολήν, ἐφ' ᾧ τὸ περὶ Κόρινθον πνεῦμα γενέσθαι συνέπεσεν.	73 The fact that comets when frequent foreshadow wind and drought must be taken as an indication of their fiery constitution. For their origin is plainly due to the plentiful supply of that secretion. Hence the air is necessarily drier and the moist evaporation is so dissolved and dissipated by the quantity of the hot exhalation as not readily to condense into water. But this phenomenon too shall be explained more clearly later when the time comes to speak of the winds.—So when there are many comets and they are dense, it is as we say, and the years are clearly dry and windy. When they are fewer and fainter this effect does not appear in the same degree, though as a rule the is found to be excessive either in duration or strength. For instance when the stone at Aegospotami fell out of the air—it had been carried up by a wind and fell down in the daytime—then too a comet happened to have appeared in the west. And at the time of the great comet the winter was dry and north winds prevailed, and the wave was due to an opposition of winds. For in the gulf a north wind blew and outside it a violent south wind. Again in the archonship of Nicomachus a comet appeared for a few days about the equinoctial circle (this one had not risen in the west), and simultaneously with it there happened the storm at Corinth.
τοῦ δὲ μὴ γίγνεσθαι πολλοὺς μηδὲ πολλάκις κομήτας, καὶ μᾶλλον ἐκτὸς τῶν τροπικῶν ἢ ἐντός, αἴτιος ἡ τοῦ ἡλίου καὶ ἡ τῶν ἀστέρων κίνησις, οὐ μόνον ἐκκρίνουσα τὸ θερμόν, ἀλλὰ καὶ διακρίνουσα τὸ συνιστάμενον. μάλιστα δ' αἴτιον ὅτι τὸ πλεῖστον εἰς τὴν τοῦ γάλακτος ἀθροίζεται χώραν.	74 That there are few comets and that they appear rarely and outside the tropic circles more than within them is due to the motion of the sun and the stars. For this motion does not only cause the hot principle to be secreted but also dissolves it when it is gathering. But the chief reason is that most of this stuff collects in the region of the milky way.

Postquam philosophus reprobavit opiniones aliorum, hic incipit ponere opinionem propriam de cometis.	68. After refuting the opinions of others, the Philosopher here begins to give his own opinion on comets.
Et primo ostendit modum certitudinis qui est in hac materia exquirendus. Et dicit quod de talibus, quae sunt immanifesta sensui, non est exquirenda certa demonstratio et necessaria, sicut in mathematicis et in his quae subiacent sensui; sed sufficit per rationem demonstrare et ostendere causam, ita quod quaestionem solvamus per aliquam solutionem possibilem, ex qua non sequatur aliquod inconveniens, per ea quae hic apparent secundum sensum. Unde hoc modo in proposito ad habendam causam est procedendum.	First, he explains the type of certitude to be sought in this matter [67] and says that with respect to such things, not accessible to sense observation, one must not look for a certain and necessary demonstration, as found in mathematics and in phenomena accessible to sense. It is enough to demonstrate with an argument and present a cause, in such a way as to solve the problem with some possible solution from which nothing impossible follows, according to what here appears to sense. Accordingly, this is the method to be employed in the present case to obtain a cause.
Secundo ibi: supponitur enim nobis etc., secundum praedictum modum incipit assignare causam de apparitione cometae. Et circa hoc duo facit:	69. Secondly, according to the aforesaid method he begins to assign a cause of the appearance of comets. About this he does two things:
primo assignat causam de apparitione cometae; secundo de loco et tempore apparitionis, ibi: eius autem quod est et cetera.	First, he assigns the cause of the appearance of comets, at 70; Secondly, of the place and time of their appearance, at 76.
Prima dividitur in duas:	The first is divided into two parts:
in prima assignat causam apparitionis cometae; secundo hoc manifestat per signum, ibi: de eo autem quod est et cetera.	In the first he gives the cause of the appearance of a comet, at 70; Secondly, he manifests this through a sign, at 75.
Circa primum duo facit:	Regarding the first he does two things:
primo ostendit cometas apparere ex duabus causis; secundo ostendit differentiam inter cometas ex diversis causis apparentes, ibi: quando quidem igitur et cetera.	First, he shows that there are two causes of comets appearing, at 70; Secondly, he shows the differences between comets that arise from diverse causes, at 74.
Circa primum tria facit. Primo resumit quaedam superius dicta, ad manifestandum propositum. Et dicit quod oportet supponere supradicta, quod huius inferioris mundi qui est circa terram, prima pars et suprema, sub corporibus circulariter motis, est exhalatio calidi et sicci. Iterum oportet supradicta supponere, quod ista exhalatio calida et sicca, et multa pars aeris, qui continuatur ad ignem, simul circumducitur circa terram sub sphaera caelesti, motu circulari, quasi delata et tracta a circulatione caeli. Et tertio oportet supponere quod exhalatio praedicta sic mota, frequenter ignitur, quocumque modo sit disposita ad hoc quod ignis in ea bene dominetur: propter quam causam fiunt discursus siderum, ut dictum est.	70. About the first he does three things: First [68], in order to manifest his proposition he re-introduces certain things already stated. And he says that we must maintain what has been said above to the effect that in the region of the lower world surrounding the earth, the first and highest part, below the bodies in circular motion, is the exhalation of the hot and dry. We must also suppose, as stated above, that this hot-dry exhalation, as well as a large portion of the air continuous with the fire, are revolved together around the earth, under the heavenly sphere, with a circular motion, as though carried and drawn along by the turning of the heaven. Thirdly, we must assume that the above-mentioned exhalation, thus moved, is frequently ignited in whatever way it happens to be disposed to allow fire to prevail well in it: this being, as was said, the cause of the shooing of certain stars.
Secundo ibi: cum igitur in talem etc., assignat causam apparitionis cometae. Et dicit quod quando talis exhalatio fuerit condensata, et propter motum superioris corporis inciderit in ipsam exhalationem aliquod principium igneum, ita scilicet quod ex aliqua parte incipiat exuri; sic quod ignis non sit tam multus ut cito exurat materiam, neque etiam sit ita debilis ut cito extinguatur priusquam accendatur, sed sit talis quod plus et diu possit permanere, cum quantitate ignis et dispositione materiae inspissatae; cum hoc etiam quod simul de inferioribus ascendat continue exhalatio bene disposita ad hunc modum exustionis, ut scilicet diu duret; tunc fit stella cometa: quia illud quod iam ignitum est videtur quasi stella, reliqua autem exhalatio, quae nondum est perfecte ignita, sed apta ignitioni, videtur coma eius. Quia qualitercumque figuretur talis exhalatio, huiusmodi figura videbitur. Quia si exhalatio sit undique circumposita stellae, idest principio vel parti ignitae, videtur quasi coma, unde et cometes dicitur: si autem disponatur ad longitudinem principii igniti, videtur exhalatio esse quasi barba stellae, et ideo vocatur pogonias, idest quasi barbatus.	71. Secondly [69], he assigns a cause for the appearance of a comet and says that when such an exhalation condenses and when, as a result of the higher body's-motion, a source of combustion falls into this exhalation and causes a flame to burst out in a certain area in such a way that the fire is neither large enough to consume all the material quickly, nor so weak as to quickly die out before a conflagration occurs, but such as to last more and for a long time, in keeping with the size of the fire and the disposition of the condensed matter; and when along with this there continually rises from below an exhalation well disposed for this type of burning, i.e., sufficient to keep it burning for a long time, then it is that comets are formed. — For the material already on fire appears to be a star, while the rest of the exhalation, which is not yet completely ignited but on the way to being ignited appears as a tail. The shape of the exhalation determines the shape that will appear: if the exhalation completely surrounds the "star," i.e., the origin or ignited part, there appears, as it were, a circle of tresses [coma], hence it is called "cometed"; but if it is disposed along the length of the ignited origin, then the exhalation appears as though the beard of the star, and is therefore said to be "pogoniated," i.e., bearded.
Tertio ibi: sicut autem talis latio etc., manifestat quod dictum est de cometa, per comparationem ad stellam cadentem. Dictum est enim supra quod motus ignis accensi in tali materia, cum fuerit motus per expulsionem, videtur esse motus stellae: et similiter mansio vel quies igniti principii in praedicta materia, videtur esse mansio vel quies stellae. Dicit autem stellam cometam quiescere, ad excludendum motum qui apparet in stellis cadentibus; non autem ad excludendum motum cometae secundum quod circumvolvitur simul cum caelo, de quo post dicet. Huiusmodi autem mansio praedicti principii accidit propter hoc, quod materia non statim consumitur; tum propter multitudinem et spissitudinem, et ignis debilitatem; tum propter aliam materiam succedentem, ut dictum est.	72. Thirdly [70], he explains what was said about a comet by comparison with a falling star. For it was said above that the motion of fire ignited in such material, when it is moved by ejection, seems to be the motion of a star; similarly, the tarrying or state of rest of the fiery principle in this matter seems to be the tarrying or state of rest of a star. He says that a comet star is at rest so as to exclude the motion which appears in falling stars, but not so as to exclude the comet's motion as it is revolved along with the heaven. He will speak of this later. The reason why the above-mentioned principle tarries is that the material is not consumed at once, owing to the amount and thickness of the material and to the weakness of the fire, as well as to the other material that replaces it, as has been said.
Et est simile sicut si aliquis in magnum cumulum palearum immiserit titionem, aut aliud quodcumque ignitum principium: non enim statim discurret, quasi exurens paleam, sed videtur ignitio diu in uno loco manere. Et ita, si quis recte consideret, videtur similitudinem quandam habere discursus stellarum cadentium apparitioni cometae. Quia in stellis discurrentibus cito procedit ignitio in longitudinem, propter dispositionem scilicet hypeccaumatis ad hoc quod de facili aduratur: sed si ignitio maneret, et non pertransiret consumendo materiam, aut materia esset multum densa, ut non posset cito consumi, tunc, quasi subtracto medio discursu, remaneret solummodo stella manens, sicut est in principio discursus et in termino.	It is as though someone threw a torch or other burning source into a large pile of chaff: the fire does not at once travel as though consuming the chaff, but the igniting seems to remain in one area for a long time. From this example properly understood one can see that the shooting of falling stars has a certain likeness to the appearance of a comet. For in shooting stars the fire travels quickly along the length on account of the disposition, namely, in the fuel, that permits it to be easily burned; but if the flame were to tarry and not pass along by consuming the matter, or if the material were very dense, so as not to be swiftly consumed, then, as though the intermediate trajectory had been taken away, there would only be the star standing, as is the case in the beginning and end of the trajectory.
Et tale quid est cometa: ut imaginemur quod cometa sit quasi stella discurrens, prout talis stella est in principio et in fine discursus, subtracto motu discursionis. Sic igitur concludit quod, quando principium consistentiae ipsius fuerit in inferiori loco, idest sub globo lunari, dicitur cometa per se apparens, sine aliqua stella errante vel fixa.	Such is the comet. Thus we can imagine a comet as though it were a shooting star, as such a star is at the beginning and end of its course but with no shooting motion. He therefore concludes that when the source of its consistency was "in a lower place," i.e., under the lunar globe, a comet is said to appear by itself, without being accompanied by any star, either wandering or fixed.
Deinde cum dicit: quando autem sub astrorum aliquo etc., assignat alium modum apparitionis cometae. Et dicit quod quando sub aliqua stellarum errantium vel non errantium, exhalatio adunatur per motum illius stellae, tunc aliqua stellarum dictarum fit cometa: non quod stella quae apparet sit aliquod igneum in aere, sicut in superiori modo dictum est, sed est verax stella, errans vel non errans; non tamen coma eius fit in loco caelesti ubi sunt astra, sed est sub caelo in aere.	73. Then [71] he describes another way in which comets appear. And he says that when an exhalation is collected under some star, wandering or not wandering, on account of the motion of that star, then some such star becomes a comet — not that the star which appears is a fiery object in the air, as in the case cited above, but it is a true star, wandering or not wandering. Its "coma," however, does not come into existence in the heavenly region where the stars are, but under the heaven in the air.
Et ponit exemplum de halo, idest de aere qui videtur aliquando circumstare solem et lunam, etiam sole et luna motis. Huiusmodi enim halo non est in loco solis et lunae, licet sequatur solem et lunam, etiam sole et luna motis: haec enim passio fit in aere condensato sub motu solis et lunae, ut infra dicetur. Sicut igitur halo se habet ad solem et lunam, ita coma se habet ad stellas fixas vel erraticas, quando apparent cum comis: et est aliqua exhalatio inferius, scilicet in superiori loco aeris, consequens motum illarum stellarum. Sed tamen haec est differentia inter halo et comam, quia color eius quod dicitur halo, non est in ipso vapore, sed est ex reverberatione ad nubem, ut infra ostendetur: sed hoc quod videtur de comis, est proprie color ipsarum exhalationum fumosarum.	And he gives the example of the "halo," i.e., of the air which sometimes is seen to surround the sun and moon, even though the sun and moon are in motion. Such a halo does not exist in the place where the sun and moon exist, though it accompany the sun and moon, even when the latter are moved. This passion comes into existence in the air condensed under the course of the sun and moon, as will be explained later. Therefore, just as a halo is to the sun and moon, so a "coma" is to the fixed stars and wanderers, whenever they appear with a "coma," which is a certain exhalation farther down, namely, in the upper region of the air, deriving from the motion of those stars. Yet there is this difference between a halo and a "coma": the color of a halo is not in the vapor itself but is something that results from reflection toward a cloud, as will be explained later; but the color associated with a "coma" is properly a color belonging to the fumid exhalations themselves.
Deinde cum dicit: quando quidem igitur etc., ostendit differentiam inter cometas secundum duos dictos modos apparentes. Et dicit quod quando adunatio exhalationis fit secundum aliquam stellam fixam vel errantem, necesse est quod in cometa manifeste videatur ille motus qui est stellae cui adhaeret coma: sed quando stella cometa est per se ignis existens in aere, sine aliqua superiorum stellarum, tunc videntur subtardantes.	74. Then at [72] he points out the difference between comets as appearing in these two ways. And he says that when the accumulation of an exhalation takes place in relation to a fixed or wandering star, it is necessary that there clearly appear in the comet the motion which belongs to the star to which the "coma" belongs; but when the comet star is fire existing per se in the air without any of the upper stars, then they seem to lag.
Et hoc manifestat per hoc quod latio inferioris mundi qui est circa terram, talis est, scilicet tardior motu caelesti: quamvis enim circumvolvatur ignis et magna pars aeris per motum firmamenti, non potest tamen attingere ad velocitatem motus caelestis. Exhalatio igitur ignita existens in superiori parte aeris, circumvolvitur solum cum aere et igne: sed quia motus horum corporum est tardior motu firmamenti, ideo cometa existens in aere remanet post corpora caelestia, quae velocissime moventur; et sic videtur habere motum contrarium firmamento, sicut et planetae, ex sola retardatione. Quod etiam quidam opinati sunt circa planetas: et inde est etiam quod praedictae opiniones posuerunt cometas esse planetas.	He explains this by the fact that the course of the lower world about the earth is such, namely, slower than the heavenly movement — for although fire and a large portion of the air are revolved by the motion of the firmament, they nevertheless cannot attain to the speed of the heavenly motion. Therefore the burning exhalation existing in the upper region of air is revolved along with the air and the fire. Because their motion is slower than that of the firmament, therefore the comet existing in the air remains behind the heavenly bodies, which are moving most rapidly. Consequently, from its slowness alone, it seems to have a movement contrary to the firmament, just as the planets do. Some indeed thought this of the planets — hence the aforesaid opinions posited that comets are planets.
Sed hoc quod cometa saepe fit per se, et frequentius quam circa aliquam stellarum determinatarum, idest fixarum, quae habent esse fixum et determinatum in caelo, maxime manifestat quod cometa non est repercussio facta in exhalatione (quam nominat hypeccauma) ad ipsam stellam cui adhaeret coma, sicut est in halo. Si autem esset sicut est in halo, fieret repercussio visus ab exhalatione ad ipsam stellam, et non ad solem, sicut dicunt sequaces Hippocratis. Sed de halo posterius dicetur.	But the very fact that a comet is often produced by itself, and this more frequently than in association with any of the "determinate," i.e., fixed, stars which have a fixed and determinate existence in the heaven, shows most plainly that a comet is not a reflexion produced in the exhalation (which he calls "hypeccauma" [fuel]) to the star to which the "coma" is attached, as is the case with a halo. But if it were as it is with a halo, the reflection of our vision would pass from the exhalation to the star, and not to the sun, as the followers of Hippocrates claim. But an account of the halo will be given later.
Deinde cum dicit: de eo autem quod est etc., manifestat quod dixerat, per signum. Et dicit quod huius quod est consistentiam cometarum esse igneam, vel quantum ad comam apparentem, argumentum est hoc, quod plures cometae significant spiritus et siccitates. Manifestum est enim quod venti et siccitates fiunt propter hoc, quod multa exhalatio sicca est segregata a terra; unde necesse est aerem esse sicciorem, et humidum quod evaporat ab aquis, rarefieri et dissolvi, propter multitudinem calidae exhalationis, ita quod non de facili vapores in aquam condensentur, sed magis generentur venti, qui causantur ex exhalationibus siccis; hoc autem erit manifestius quando dicetur de ventis. Sic igitur, quando apparent frequentes et multi cometae, quod accidit propter multitudinem exhalationis siccae, oportet quod anni sint notabiliter sicci et ventosi. Sed quando rarius fiunt cometae, et non ita magni fiunt, non sunt anni notabiliter sicci et ventosi; sed tamen, ut frequenter, fit excessus venti, aut secundum tempus, quia diu durat, aut secundum magnitudinem, quia vehementer flat.	75. Then [73] he manifests what he had said, through a sign. And he says that an argument to show that the stuff of comets is fiery, or so far as the fringe [coma] appears, is that a number of comets is a herald of winds and droughts. For it is plain that winds and droughts are the result of much dry exhalation being drawn from the earth; as a result, the air is quite dry and the moisture which evaporates from the seas is rarified and dissolved by the abundance of hot exhalation; consequently, vapors are not easily condensed into water; rather, winds caused from the dry exhalations are generated. This will become clearer when winds are discussed. Thus, therefore, when frequent and numerous comets appear, which occurs as a result of the abundance of dry exhalation, the years are necessarily unusually dry and windy. But when the comets are less frequent, and not so large, the years are not notably dry and windy; yet frequently there is an excess of wind, either in duration because they last long, or in strength, because they blow furiously.
Et ponit exempla. Aliquando enim in quibusdam fluviis cecidit lapis ex aere per diem, elevatus a vento; et tunc fuit factus quidam cometa circa vesperum. Et similiter circa illum magnum cometam de quo supra dixit, fuit hiems sicca et borealis, et propter contrarietatem ventorum factus fuit superexcessus fluctuum, ita quod propter hoc destructae dicuntur quaedam civitates; quia extra in pelago flabat magnus Auster, sed in sinu vincebat Boreas. Similiter sub principe Nicomacho apparuit quidam cometa, et tunc etiam fuit factus magnus ventus apud Corinthum.	He gives examples. For sometimes a stone dropped into certain rivers from the air during the day, having been lifted by the wind; and then, that evening, a comet was formed. And the same is true of that large comet he referred to earlier: it was a dry winter with prevailing north winds, and because of contrary winds a tidal wave resulted and some cities are said to have been destroyed — for out on the sea a strong south wind was blowing, but in the bay a north wind prevailed. Likewise, under the rule of Nicomachus, a certain comet appeared and then a strong wind blew up in Corinth.
Deinde cum dicit: eius autem quod est etc., assignat causam de loco et tempore apparitionis cometae. Et dicit quod causa eius quod non fiant multi neque saepe, et magis extra tropicos, idest extra viam solis, quam intra, est quod per motum solis et astrorum non solum sunt exhalationes calidae a terra resolutae, sed etiam, si aliquid est in huiusmodi exhalationibus consistens et spissum, per motum solis et stellarum disgregatur; et sic impeditur causa apparitionis cometae, nisi quando fuerit superabundans talis exhalationis multiplicatio, quod raro accidit. Et maxime etiam causa est rarae apparitionis cometarum, quia plurimum de materia tali ex qua causatur apparitio cometae, adunatur in regione lactei circuli, ut infra dicetur: unde raro tantum multiplicatur exhalatio, quod sufficiat apparitioni cometae et lactei circuli.	76. Then [74] he assigns the cause for the place and time of a comet's appearance. And he says that the reason why comets are few and infrequent and occur more often outside the "tropics," i.e., outside the sun's path, than within, is that the motion of the sun and stars not only releases the hot exhalations resolved from the earth, but also breaks up any consistency and thickness that might be in them. In this way the cause of a comet's appearing is hindered except in cases when there is a superabundant accumulation of such exhalations, which happens rarely. The main reason why comets appear rarely is that most of the matter which causes the appearance of comets is accumulated in the region of the milky circle, as will be said later: hence it is rarely that enough exhalation accumulates to account for the appearance both of a comet and of the "milky circle."

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Lecture 12 Opinions of others on the Milky Way
Chapter 8
ὅπως δὲ καὶ διὰ τίν' αἰτίαν γίγνεται καὶ τί ἐστι τὸ γάλα, λέγωμεν ἤδη. προδιέλθωμεν δὲ καὶ περὶ τούτου τὰ παρὰ τῶν ἄλλων εἰρημένα πρῶτον.	75 Let us now explain the origin, cause, and nature of the milky way. And here too let us begin by discussing the statements of others on the subject.
τῶν μὲν οὖν καλουμένων Πυθαγορείων φασί τινες ὁδὸν εἶναι ταύτην οἱ μὲν τῶν ἐκπεσόντων τινὸς ἀστέρων, κατὰ τὴν λεγομένην ἐπὶ Φαέθοντος φθοράν, οἱ δὲ τὸν ἥλιον τοῦτον τὸν κύκλον φέρεσθαί ποτέ φασιν οἷον οὖν διακεκαῦσθαι τὸν τόπον τοῦτον ἤ τι τοιοῦτον ἄλλο πεπονθέναι πάθος ὑπὸ τῆς φορᾶς αὐτῶν.	76 (1) Of the so-called Pythagoreans some say that this is the path of one of the stars that fell from heaven at the time of Phaethon's downfall. Others say that the sun used once to move in this circle and that this region was scorched or met with some other affection of this kind, because of the sun and its motion.
ἄτοπον δὲ τὸ μὴ συννοεῖν ὅτι εἴπερ τοῦτ' ἦν τὸ αἴτιον, ἔδει καὶ τὸν τῶν ζῳδίων κύκλον οὕτως ἔχειν, καὶ μᾶλλον ἢ τὸν τοῦ γάλακτος ἅπαντα γὰρ ἐν αὐτῷ φέρεται τὰ πλανώμενα καὶ οὐχ ὁ ἥλιος μόνος. δῆλος δ' ἡμῖν ἅπας ὁ κύκλος αἰεὶ γὰρ αὐτοῦ φανερὸν ἡμικύκλιον τῆς νυκτός. ἀλλὰ πεπονθὼς οὐδὲν φαίνεται τοιοῦτον, πλὴν εἴ τι συνάπτει μόριον αὐτοῦ πρὸς τὸν τοῦ γάλακτος κύκλον.	77 But it is absurd not to see that if this were the reason the circle of the Zodiac ought to be affected in the same way, and indeed more so than that of the milky way, since not the sun only but all the planets move in it. We can see the whole of this circle (half of it being visible at any time of the night), but it shows no signs of any such affection except where a part of it touches the circle of the milky way.
οἱ δὲ περὶ Ἀναξαγόραν καὶ Δημόκριτον φῶς εἶναι τὸ γάλα λέγουσιν ἄστρων τινῶν τὸν γὰρ ἥλιον ὑπὸ τὴν γῆν φερόμενον οὐχ ὁρᾶν ἔνια τῶν ἄστρων. ὅσα μὲν οὖν περιορᾶται ὑπ' αὐτοῦ, τούτων μὲν οὐ φαίνεσθαι τὸ φῶς (κωλύεσθαι γὰρ ὑπὸ τῶν τοῦ ἡλίου ἀκτίνων) ὅσοις δ' ἀντιφράττει ἡ γῆ ὥστε μὴ ὁρᾶσθαι ὑπὸ τοῦ ἡλίου, τὸ τούτων οἰκεῖον φῶς εἶναί φασι τὸ γάλα. φανερὸν δ' ὅτι καὶ τοῦτ' ἀδύνατον τὸ μὲν γὰρ γάλα ἀεὶ τὸ αὐτὸ ἐν τοῖς αὐτοῖς ἐστιν ἄστροις (φαίνεται γὰρ μέγιστος ὢν κύκλος),	78 (2) Anaxagoras, Democritus, and their schools say that the milky way is the light of certain stars. For, they say, when the sun passes below the earth some of the stars are hidden from it. Now the light of those on which the sun shines is invisible, being obscured by the of the sun. But the milky way is the peculiar light of those stars which are shaded by the earth from the sun's rays.
ὑπὸ δὲ τοῦ ἡλίου ἀεὶ ἕτερα τὰ οὐχ ὁρώμενα διὰ τὸ μὴ ἐν ταὐτῷ μένειν τόπῳ. ἔδει οὖν μεθισταμένου τοῦ ἡλίου μεθίστασθαι καὶ τὸ γάλα νῦν δὲ οὐ φαίνεται τοῦτο γιγνόμενον.	79 This, too, is obviously impossible. The milky way is always unchanged and among the same constellations (for it is clearly a greatest circle), whereas, since the sun does not remain in the same place, what is hidden from it differs at different times. Consequently with the change of the sun's position the milky way ought to change its position too: but we find that this does not happen.
πρὸς (345b.) δὲ τούτοις, εἰ καθάπερ δείκνυται νῦν ἐν τοῖς περὶ ἀστρολογίαν θεωρήμασιν, τὸ τοῦ ἡλίου μέγεθος μεῖζόν ἐστιν ἢ τὸ τῆς γῆς καὶ τὸ διάστημα πολλαπλασίως μεῖζον τὸ τῶν ἄστρων πρὸς τὴν γῆν ἢ τὸ τοῦ ἡλίου, καθάπερ τὸ τοῦ ἡλίου πρὸς τὴν γῆν ἢ τὸ τῆς σελήνης, οὐκ ἂν πόρρω που τῆς γῆς ὁ κῶνος ὁ ἀπὸ τοῦ ἡλίου συμβάλλοι τὰς ἀκτῖνας, οὐδ' ἂν ἡ σκιὰ πρὸς τοῖς ἄστροις εἴη τῆς γῆς, ἡ καλουμένη νύξ ἀλλ' ἀνάγκη πάντα τὸν ἥλιον τὰ ἄστρα περιορᾶν, καὶ μηδενὶ τὴν γῆν ἀντιφράττειν αὐτῶν.	80 Besides, if astronomical demonstrations are correct and the size of the sun is greater than that of the earth and the distance of the stars from the earth many times greater than that of the sun (just as the sun is further from the earth than the moon), then the cone made by the rays of the sun would terminate at no great distance from the earth, and the shadow of the earth (what we call night) would not reach the stars. On the contrary, the sun shines on all the stars and the earth screens none of them.
ἔτι δ' ἐστὶν τρίτη τις ὑπόληψις περὶ αὐτοῦ λέγουσιν γάρ τινες ἀνάκλασιν εἶναι τὸ γάλα τῆς ἡμετέρας ὄψεως πρὸς τὸν ἥλιον, ὥσπερ καὶ τὸν ἀστέρα τὸν κομήτην.	81 (3) There is a third theory about the milky way. Some say that it is a reflection of our sight to the sun, just as they say that the comet is.
ἀδύνατον δὲ καὶ τοῦτο εἰ μὲν γὰρ τό τε ὁρῶν ἠρεμοίη καὶ τὸ ἔνοπτρον καὶ τὸ ὁρώμενον ἅπαν, ἐν τῷ αὐτῷ σημείῳ τοῦ ἐνόπτρου τὸ αὐτὸ φαίνοιτ' ἂν μέρος τῆς ἐμφάσεως εἰ δὲ κινοῖτο τὸ ἔνοπτρον καὶ τὸ ὁρώμενον ἐν τῷ αὐτῷ μὲν ἀποστήματι πρὸς τὸ ὁρῶν καὶ ἠρεμοῦν, πρὸς ἄλληλα δὲ μήτε ἰσοταχῶς μηδ' ἐν τῷ αὐτῷ ἀεὶ διαστήματι, ἀδύνατον τὴν αὐτὴν ἔμφασιν ἐπὶ τοῦ αὐτοῦ εἶναι μέρους τοῦ ἐνόπτρου. τὰ δ' ἐν τῷ τοῦ γάλακτος κύκλῳ φερόμενα ἄστρα κινεῖται καὶ ὁ ἥλιος πρὸς ὃν ἡ ἀνάκλασις, μενόντων ἡμῶν, καὶ ὁμοίως καὶ ἴσον πρὸς ἡμᾶς ἀπέχοντα, αὐτῶν δ' οὐκ ἴσον ὁτὲ μὲν γὰρ μέσων νυκτῶν ὁ δελφὶς ἐπιτέλλει, ὁτὲ δὲ ἕωθεν, τὰ δὲ μόρια τοῦ γάλακτος τὰ αὐτὰ μένει ἐν ἑκάστῳ. καίτοι οὐκ ἔδει, εἰ ἦν ἔμφασις, ἀλλὰ μὴ ἐν αὐτοῖς τι ἦν τοῦτο τὸ πάθος τοῖς τόποις.	82 But this too is impossible. For if the eye and the mirror and the whole of the object were severally at rest, then the same part of the image would appear at the same point in the mirror. But if the mirror and the object move, keeping the same distance from the eye which is at rest, but at different rates of speed and so not always at the same interval from one another, then it is impossible for the same image always to appear in the same part of the mirror. Now the constellations included in the circle of the milky way move; and so does the sun, the object to which our sight is reflected; but we stand still. And the distance of those two from us is constant and uniform, but their distance from one another varies. For the Dolphin sometimes rises at midnight, sometimes in the morning. But in each case the same parts of the milky way are found near it. But if it were a reflection and not a genuine affection of these this ought not to be the case.
ἔτι δὲ νύκτωρ ἐν ὕδατι καὶ τοῖς τοιούτοις ἐνόπτροις τὸ μὲν γάλα ἐμφαίνεται θεωροῦσι, τὸ δὲ τὴν ὄψιν ἀνακλᾶσθαι πρὸς τὸν ἥλιον πῶς δυνατόν;	83 Again, we can see the milky way reflected at night in water and similar mirrors. But under these circumstances it is impossible for our sight to be reflected to the sun.
ὅτι μὲν οὖν οὔτε ὁδὸς τῶν πλανήτων οὐδενὸς οὔτε φῶς ἐστι τῶν μὴ ὁρωμένων ἄστρων οὔτ' ἀνάκλασις, ἐκ τούτων φανερόν. σχεδὸν δὲ ταῦτ' ἐστὶν μόνον τὰ μέχρι τοῦ νῦν παραδεδομένα παρὰ τῶν ἄλλων	84 These considerations show that the milky way is not the path of one of the planets, nor the light of imperceptible stars, nor a reflection. And those are the chief theories handed down by others hitherto.

Postquam philosophus determinavit de stellis cadentibus et cometis, nunc determinat de lacteo circulo.	77. After determining concerning falling stars and comets, the Philosopher here determines concerning the milky circle.
Et primo ostendit de quo est intentio. Et dicit quod iam dicendum est de lacteo circulo, qualiter et propter quam causam est apparitio eius, et quid est illa claritas quae est quasi lac; hoc servato ordine, ut primo discutiamus ea quae ab aliis dicta sunt. Secundo ibi: vocatorum quidem igitur etc., exequitur propositum.	First, he states his intention [75] and says that we must talk now of the milky circle: the how and why of its appearance and what that milky brightness is. But we shall adhere to that order whereby we first discuss what others have said; Secondly, he executes his proposition, at 78.
Et primo ponit opiniones aliorum; secundo opinionem propriam, ibi: nos autem dicamus et cetera.	First he presents the opinions of others, at 78; Secondly, his own opinion (L. 13).
Prima dividitur in tres, secundum tres opiniones quas ponit: secunda incipit ibi: qui autem circa Anaxagoram etc.; tertia ibi: amplius autem est tertia et cetera.	The first is divided into three parts according to the three opinions he cited; The second opinion begins at 80; The third at 83.
Circa primum duo facit. Primo ponit opinionem. Et dicit quod quidam de numero philosophorum qui vocantur Pythagorici, dixerunt quod lacteus circulus est quaedam via. Sed in hoc diversificati sunt: quidam enim dixerunt quod erat via alicuius stellae quae per hanc partem caeli transivit, derelicto proprio cursu, tempore exorbitationis caeli, quae dicitur in fabulis fuisse facta sub Phaetonte; sed alii dicunt quod per istum circulum quandoque transivit sol. Et ita per motum solis vel stellae, locus iste caeli est quasi exustus, vel passus aliquam talem passionem, ut videatur ibi quaedam albedo.	78. Regarding the first he does two things. First, he presents the opinion at [76] and says that some of the philosophers called "Pythagoreans" held that the milky circle is a certain path. But their opinions differed: for some asserted that it was the path of a certain star that passed through this part of the heaven after abandoning its own course when the heavens once went off the path — an event which the fables declare happened under Phaethon. Others say that the sun once travelled that path. Consequently, by the motion of the sun or of a star that area of the heaven was, so to speak, scorched, or affected in such a way that a patch of whiteness now appears there.
Secundo ibi: inconveniens autem etc., improbat hanc opinionem. Et dicit quod inconveniens fuit quod ponentes hanc opinionem non simul intelligebant quod, si transitus solis vel stellae esset causa huius claritatis in hac parte caeli, multo magis oportebat quod haec dispositio esset in circulo zodiaco, quam in circulo lacteo: quia non solum sol, sed omnes stellae errantes feruntur per zodiacum. Circulus autem zodiacus totus manifestus est nobis, diversis temporibus, quia de nocte semper apparet medietas zodiaci super terram (terra enim obtinet vicem puncti respectu sphaerae stellarum fixarum: unde per grossitiem terrae nihil occultatur nobis de zodiaco): sed quamvis totus zodiacus sit a nobis visibilis, tamen non videtur in eo aliqua talis dispositio, nisi in parte qua coniungitur lacteo circulo.	79. Secondly [77], he rejects this opinion and says that it is an inconsistency for those who posited this opinion that they did not at the same time see that, if the journey of the sun or a star were the cause of this brightness in this region of the heaven, such a disposition has much more reason for appearing in the circle of the Zodiac than in the milky circle — for not only the sun, but all the wandering stars move through the Zodiac. Now the whole zodiacal circle is visible to us, at different times, because at night half of it always appears above the earth (for the earth has the status of a point compared to the sphere of the fixed stars: hence earth's largeness does not conceal anything in the Zodiac from us); but although the entire Zodiac is visible to us, no such disposition appears in it, save in the region where it is joined with the milky circle.
Deinde cum dicit: qui autem circa Anaxagoram etc., ponit secundam opinionem. Et primo recitat eam. Et dicit quod sectatores Anaxagorae et Democriti dixerunt claritatem lacteam quae apparet in caelo, esse lumen quarundam stellarum. Cum enim sol fertur sub terra, dicebant quod umbra terrae pertingit usque ad sphaeram stellarum fixarum, et occultat quasdam stellas, ne recipiant radios solis; non autem omnes, quia propter parvitatem terrae, umbra eius non occupat totum caelum, sed aliquam parvam partem. Dicebant enim quod claritas stellarum quae respiciuntur a sole, non apparet, quia prohibetur apparere a radiis solis ad eas pertingentibus; et sic circa eas non videtur claritas lactis. Sed illarum stellarum ad quas non pertingunt radii solis, impediente terra, apparet proprium lumen; quod dicebant esse claritatem lactis.	80. Then [78] he presents the second opinion. First, he recites it and says that the followers of Anaxagoras and Democritus declared that the milky brightness which appears in the heaven is the light of certain stars. For when the sun is borne below the earth, they said, the earth's shadow reaches as far as the sphere of the fixed stars and covers some of them so that they do not receive the sun's rays; yet it does not cover all of them, because, due to the smallness of the earth, its shadow does not cover the entire heaven but only a small area. For they said that the brightness of the stars faced by the sun does not appear, because it is prevented from appearing by the sun's rays reaching them; consequently, no milky brightness surrounds them. But of the stars which the sun's rays do not reach, because the earth prevents this, their own light appears, which they identify as the milky brightness.
Secundo ibi: manifestum est autem etc., reprobat hanc opinionem per duas rationes. Quarum primam ponit, dicens manifestum esse hoc quod dictum est esse impossibile. Quia claritas lactis semper apparet in eisdem stellis: quia circulus lacteus videtur esse unus de maximis circulis sphaerae, qui dividit eam per medium. Sed quia sol non semper manet in eodem loco caeli, oportet quod semper sint alia et alia astra quae occultantur radiis solis per umbram terrae: quia oportet imaginari motum umbrae in oppositum motui solis. Si igitur occultatio stellarum per umbram terrae esset causa apparitionis lacteae claritatis, oporteret, moto sole, transferri et lacteam claritatem. Sed hoc non videtur fieri, quia semper apparet in eodem loco et in eisdem stellis, ut dictum est. Falsa est igitur praedicta opinio.	81. Secondly [79], he rejects this opinion for two reasons. In presenting the first of them he says that what it claims is impossible. For the milky brightness always appears in the same stars — the milky circle being seen to be one of the largest circles, which divide the sphere in half. But because the sun does not always remain in the same place in the heaven, other and other stars must always be being obscured from the sun's rays by the earth's shadow — since the shadow's motion must be imagined as opposite to the sun's course. Therefore, if the cause of the milky brightness' visibility were the earth's shadow blotting out the stars, then as the sun moved, the milky brightness would also have to shift. But this is not seen to happen, because it always appears in the same place and in the same stars, as was said. Consequently, the aforesaid theory is false.
Secundam rationem ponit ibi: adhuc autem si quemadmodum etc., dicens quod probatum est per astrologicas rationes et considerationes, quod sol est maior terra, et quod plus distant astra fixa a terra quam sol, sicut et sol plus quam luna. Quando autem corpus lucidum est maius corpore opaco ex cuius oppositione fit umbra, umbra non ascendit in immensum, sed pyramidaliter ascendit in conum usque ad aliquam quantitatem; et tanto minorem, quanto corpus lucidum minus distat a corpore opaco, et quanto magis excedit ipsum. Unde manifestum est quod non multum longe conus umbrae terrae proiicitur ad radios qui sunt a sole, neque umbra terrae, quae vocatur nox, est apud astra fixa: sed necesse est quod sol prospiciat omnia astra fixa, et quod nulli eorum obsistat terra. Obsistit autem lunae eclipsans ipsam, quia est inferior sole, ut dictum est. Et sic patet quod praedicta opinio falsum supponebat.	82. He gives the second reason [80] and says that astronomical arguments and considerations prove that the sun is larger than earth and that the fixed stars are much farther from the earth than the sun is, just as the sun is farther from us than the moon is. Now when a shining body is larger than the opaque body whose interposition produces a shadow, the shadow does not increase indefinitely, rather it ascends in pyramid form to a cone of a certain quantity which is proportionately less as the shining body is less distant from the opaque one, and the more the former's size exceeds the latter's. Hence it is plain that the cone of the earth's shadow is not projected very far with respect to the rays coming from the sun; neither does the earth's shadow, which we call "night," reach as far as the fixed stars. What has to happen is that the sun has a view of all the fixed stars and that the earth blankets none of them. The reason why it blankets the moon and eclipses it is that the moon is lower than the sun, as has been said. Consequently, it is plain that the theory under discussion presupposed something false.
Tertiam opinionem ponit ibi: amplius autem est tertia et cetera. Et primo recitat ipsam, dicens quod quaedam tertia opinio fuit de circulo lacteo. Dixerunt enim quidam quod claritas lactea est ex eo quod visus noster repercutiebatur a stellis quibusdam ad solem; et ideo apparebat claritas circa illas stellas repercutientes visum, ita quod sunt quasi quoddam speculum claritatis solaris, sicut et Hippocrates dixit de apparitione cometae.	83. He presents the third opinion [81], and first he recites it, saying that there is a certain third theory about the milky circle. For some said that the milky brightness is due to our vision's being reflected from certain stars to the sun; as a result a brightness appeared around those stars striking our vision, so that they act as a certain mirror for the sun's brilliance, as Hippocrates also said when explaining the appearance of comets.
Secundo ibi: impossibile autem etc., improbat hanc opinionem per duas rationes. Quarum primam ponit, dicens quod impossibile est quod praedicta opinio ponit. Et praemittit hanc propositionem. Si omne, idest totum hoc, scilicet videns et speculum et res quae videtur per speculum, immobilis maneat, necesse est quod eadem pars emphaseos, idest formae apparentis, appareat in eodem signo speculi, idest in eodem puncto ad quod fit repercussio lineae visualis. Sed si speculum moveatur, et similiter res visa per speculum, videns autem quiescat; et illa duo quae moventur, semper remaneant in eadem distantia ad videntem, sed adinvicem comparata neque aequali velocitate moventur, neque sunt semper in eadem distantia; impossibile est quod eadem apparitio fiat in eadem parte speculi. Quia nihil differt quod speculum et res visa moveantur diversa velocitate, quam si unum moveretur et alterum quiesceret: quod si esset, manifestum est quod videretur in alia et alia parte speculi forma rei visae, propter diversam oppositionem secundum situm. Et hoc dico si videns quiescat: quia si videns moveatur, et speculum quiesceret, et res visa moveatur, posset forma rei visae apparere in eadem parte speculi; quia per motum videntis recompensaretur quod deesset motu rei visae, si sic proportionaliter moverentur. Unde oportet quod, quando videns quiescit, et speculum et res visa moventur inaequali velocitate, quod forma non appareat in eadem parte speculi.	84. Secondly [82], he rejects this theory for two reasons. He sets down the first of these and says that the above opinion posits something impossible. And he lays down this proposition: If "everything," i.e., the entire system, namely, the beholder, the mirror, and the object seen by means of the mirror, all remain at rest, then of necessity the same part of the "emphaseos," i.e., of the form appearing, will appear "on the same sign of the mirror," i.e., at the same point at which the reflection of the visual line took place. But if the mirror should move, and likewise the object seen by means of the mirror, while the beholder remains at rest, and if the two things in motion always remain at the same distance from the beholder, but with respect to one another are neither moving with equal speeds nor always at the same distance, then under these conditions it is impossible for the same appearance to occur in the same part of the mirror. For in practice it makes no difference whether the mirror and the thing seen are moving with unequal speeds, or one is in motion and the other at rest; and if this latter were the case, it is plain that the figure of the thing seen would appear now in one spot and now in another spot of the mirror, on account of the varying opposition according to position. And I say this, if the beholder is at rest: for if the beholder were to move, and the mirror remain at rest, while the object moved, then the figure of the thing seen could appear in the same spot on the mirror — since the beholder's motion could compensate for what was lacking due to the motion of the object seen, if they were thus proportionately moved. Hence, when the beholder remains at rest but the mirror and the thing seen are moved at unequal speeds, it is necessary that the figure not appear at the same spot on the mirror.
Sed astra quae sunt in circulo lacteo existentia, quae ponuntur quasi speculum, moventur; et similiter sol movetur, ad quem ponitur fieri repercussio visus, et sic obtinet locum rei visae; nos autem, qui sumus videntes, quiescimus, propter quietem terrae (motus autem quo movemur per terram, non facit aliquam sensibilem differentiam respectu tantae magnitudinis); astra autem praedicta et sol moventur aequaliter nobis quidem, et distantia eorum semper (est) aequalis nobis. Quod non est sic intelligendum, quod aequalis sit distantia a nobis ad solem, distantiae quae est a nobis ad stellas, cum supra dictum sit quod stellae sunt supra solem; sed quod sol per motum suum non fit a nobis magis vel minus distans. Et similiter convenit stellae: ut intelligatur maior vel minor distantia, quae sit notabilis respectu distantiae quae est inter solem et stellas; et hoc propter parvitatem terrae. Sed a seipsis sol et stellae non semper distant aequaliter: quia Delphis, hoc est constellatio delphini, quae est in lacteo circulo, quandoque oritur in media nocte, quandoque autem diluculo; et manifestum est quod plus distat a sole quando oritur in media nocte, quam quando oritur diluculo. Sed partes lactei circuli semper manent in eodem loco: quod non oportebat si esset apparitio ex repercussione proveniens; non enim esset haec claritas in eisdem locis, ut ostensum est. Unde patet praedictam opinionem esse falsam.	But the stars in the milky circle that are assumed to be a mirror, are in motion; moreover, there is motion of the sun, to which a reflection of our vision is assumed to take place'(the sun therefore plays the role of the thing seen); but we, the beholders, are at rest, because the earth is at rest (for the motion involved by our moving about on the earth makes no perceptible difference with respect to so great a size. Furthermore, the stars in question and the sun are equally moved in relation to us and their distance from us always remains the same. This does not mean that our distance from the sun is equal to our distance from the stars (for it has been previously said that the stars are higher than the sun), but that the sun, by its motion, does not increase or decrease its distance from us. And the same is true of a star. And by a "greater or less distance" is to be understood a distance that is significant with respect to the distance between the sun and the stars: we say this because of the smallness of the earth. But in relation to one another, the sun and the stars are not always equidistant: because "Delphis," i.e., the constellation of the Dolphin, which is in the milky circle, rises sometimes in the middle of the night and sometimes at dawn; and it is plain that this constellation is farther from the sun when it appears at night than when it appears at dawn. But the parts of the milky circle remain forever in the same place — which should not be the case if it were an appearance caused by a reflexion; for this brightness would not exist in the same place, as has been shown. Hence it is plain that the aforesaid theory is false.
Secundam rationem ponit ibi: adhuc autem nocte et cetera. Et dicit quod de nocte in aqua et aliis huiusmodi corporibus specularibus aspicitur forma lactei circuli. Sed inconveniens est dicere quod tunc visus repercutiatur ab aqua ad solem: vel propter distantiam enim videtur valde inconveniens quod sint ibi duae repercussiones, una scilicet ab aqua ad lacteum circulum, et alia a lacteo circulo ad solem.	85. He gives the second reason [83] and says that at night the form of the milky circle appears in water and other such mirror-like bodies. But it is inadmissible to say that in these cases vision is reflected by the water to the sun — in other words, considering the distances involved, it seems most unacceptable that there should be two reflections: one, namely, from the water to the milky circle, and another from the milky circle to the sun.
Ultimo autem epilogando concludit quod lacteus circulus neque est via alicuius planetarum, ut prima opinio dixit; neque est lumen stellarum quae non respiciuntur a sole, ut dixit secunda opinio; neque est repercussio visus a stellis ad solem, ut dixit tertia opinio. Hae enim opiniones fuerunt ante eum de Galaxia.	Finally, in summary he concludes that the milky circle is neither the path of any of the planets, as the first opinion held; nor the light of certain stars not regarded by the sun, as the second opinion said; nor the reverberation of our vision from the stars to the sun, as the third opinion maintained. And before his time these were the prevailing opinions about the "galaxy" [Milky Way].

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Lecture 13 The Milky Way, according to Aristotle
Chapter 8 cont.
ἡμεῖς δὲ λέγωμεν ἀναλαβόντες τὴν ὑποκειμένην ἀρχὴν ἡμῖν. εἴρηται γὰρ πρότερον ὅτι τὸ ἔσχατον τοῦ λεγομένου ἀέρος δύναμιν ἔχει πυρός, ὥστε τῇ κινήσει διακρινομένου τοῦ ἀέρος ἀποκρίνεσθαι τοιαύτην σύστασιν οἵαν καὶ τοὺς κομήτας ἀστέρας εἶναί φαμεν.	85 Let us recall our fundamental principle and then explain our views. We have already laid down that the outermost part of what is called the air is potentially fire and that therefore when the air is dissolved by motion, there is separated off a kind of matter—and of this matter we assert that comets consist.
τοιοῦτον δὴ δεῖ νοῆσαι γιγνόμενον ὅπερ ἐπ' ἐκείνων, ὅταν μὴ αὐτὴ (346a.) καθ' αὑτὴν γένηται ἡ τοιαύτη ἔκκρισις, ἀλλ' ὑπό τινος τῶν ἄστρων ἢ τῶν ἐνδεδεμένων ἢ τῶν πλανωμένων τότε γὰρ οὗτοι φαίνονται κομῆται διὰ τὸ παρακολουθεῖν αὐτῶν τῇ φορᾷ ὥσπερ τῷ ἡλίῳ τὴν τοιαύτην σύγκρισιν, ἀφ' ἧς διὰ τὴν ἀνάκλασιν τὴν ἅλω φαίνεσθαί φαμεν, ὅταν οὕτω τύχῃ κεκραμένος ὁ ἀήρ.	86 We must suppose that what happens is the same as in the case of the comets when the matter does not form independently but is formed by one of the fixed stars or the planets. Then these stars appear to be fringed, because matter of this kind follows their course. In the same way, a certain kind of matter follows the sun, and we explain the halo as a reflection from it when the air is of the right constitution.
ὃ δὴ καθ' ἕνα συμβαίνει τῶν ἀστέρων, τοῦτο δεῖ λαβεῖν γιγνόμενον περὶ ὅλον τὸν οὐρανὸν καὶ τὴν ἄνω φορὰν ἅπασαν εὔλογον γάρ, εἴπερ ἡ ἑνὸς ἄστρου κίνησις, καὶ τὴν τῶν πάντων ποιεῖν τι τοιοῦτον καὶ ἐκριπίζειν ἀέρα τε καὶ διακρίνειν διὰ τὸ τοῦ κύκλου μέγεθος. <�ἀνάγκη τοίνυν τῶν αὐτῶν μεγίστων κύκλων μάλιστα τὴν μέλλουσαν τοῦτο ποιήσειν φοράν... χρὴ γὰρ τοῦτο, ἵνα πολλὴ κίνησις ᾖ διὰ τὸ μέγεθος γιγνομένη καὶ πλείονα τὴν ἔξαψιν ποιήσῃ.> καὶ πρὸς τούτοις ἔτι καθ' ὃν τόπον πυκνότατα καὶ πλεῖστα καὶ μέγιστα τυγχάνουσιν ὄντα τῶν ἄστρων.	87 Now we must assume that what happens in the case of the stars severally happens in the case of the whole of the heavens and all the upper motion. For it is natural to suppose that, if the motion of a single star excites a flame, that of all the stars should have a similar result, and especially in that region in which the stars are biggest and most numerous and nearest to one another.
ὁ μὲν οὖν τῶν ζῳδίων διὰ τὴν τοῦ ἡλίου φορὰν καὶ τὴν τῶν πλανητῶν διαλύει τὴν τοιαύτην σύστασιν διόπερ οἱ πολλοὶ τῶν κομητῶν ἐκτὸς γίγνονται τῶν τροπικῶν. ἔτι δ' οὔτε περὶ τὸν ἥλιον οὔτε περὶ σελήνην γίγνεται κόμη θᾶττον γὰρ διακρίνουσιν ἢ ὥστε συστῆναι τοιαύτην σύγκρισιν. οὗτος δ' ὁ κύκλος ἐν ᾧ τὸ γάλα φαίνεται τοῖς ὁρῶσιν, ὅ τε μέγιστος ὢν τυγχάνει καὶ τῇ θέσει κείμενος οὕτως ὥστε πολὺ τοὺς τροπικοὺς ὑπερβάλλειν. πρὸς δὲ τούτοις ἄστρων ὁ τόπος πλήρης ἐστὶν τῶν μεγίστων καὶ λαμπροτάτων, καὶ ἔτι τῶν σποράδων καλουμένων (τοῦτο δ' ἐστὶν καὶ τοῖς ὄμμασιν ἰδεῖν φανερόν), ὥστε διὰ ταῦτα συνεχῶς καὶ ἀεὶ ταύτην πᾶσαν ἀθροίζεσθαι τὴν σύγκρισιν.	88 Now the circle of the zodiac dissolves this kind of matter because of the motion of the sun and the planets, and for this reason most comets are found outside the tropic circles. Again, no fringe appears round the sun or moon: for they dissolve such matter too quickly to admit of its formation. But this circle in which the milky way appears to our sight is the greatest circle, and its position is such that it extends far outside the tropic circles. Besides the region is full of the biggest and brightest constellations and also of what called 'scattered' stars (you have only to look to see this clearly). So for these reasons all this matter is continually and ceaselessly collecting there.
σημεῖον δέ καὶ γὰρ αὐτοῦ τοῦ κύκλου πλέον τὸ φῶς ἐστιν ἐν θατέρῳ ἡμικυκλίῳ τῷ τὸ δίπλωμα ἔχοντι ἐν τούτῳ γὰρ πλείω καὶ πυκνότερά ἐστιν ἄστρα ἢ ἐν θατέρῳ, ὡς οὐ δι' ἑτέραν τιν' αἰτίαν γιγνομένου τοῦ φέγγους ἢ διὰ τὴν τῶν ἄστρων φοράν εἰ γὰρ ἔν τε τῷ κύκλῳ τούτῳ γίγνεται ἐν ᾧ τὰ πλεῖστα κεῖται τῶν ἄστρων, καὶ αὐτοῦ τοῦ κύκλου ἐν ᾧ μᾶλλον φαίνεται καταπεπυκνῶσθαι καὶ μεγέθει καὶ πλήθει ἀστέρων, ταύτην εἰκὸς ὑπολαβεῖν οἰκειοτάτην αἰτίαν εἶναι τοῦ πάθους. θεωρείσθω δ' ὅ τε κύκλος καὶ τὰ ἐν αὐτῷ ἄστρα ἐκ τῆς ὑπογραφῆς. τοὺς δὲ σποράδας καλουμένους οὕτω μὲν εἰς τὴν σφαῖραν οὐκ ἔσται τάξαι διὰ τὸ μηδεμίαν διὰ τέλους ἔχειν φανερὰν ἕκαστον θέσιν, εἰς δὲ τὸν οὐρανὸν ἀναβλέπουσίν ἐστι δῆλον ἐν μόνῳ γὰρ τούτῳ τῶν κύκλων τὰ μεταξὺ πλήρη τοιούτων ἀστέρων ἐστίν, ἐν δὲ τοῖς ἄλλοις διαλείπει (346b.) φανερῶς.	89 A proof of the theory is this: In the circle itself the light is stronger in that half where the milky way is divided, and in it the constellations are more numerous and closer to one another than in the other half; which shows that the cause of the light is the motion of the constellations and nothing else. For if it is found in the circle in which there are most constellations and at that point in the circle at which they are densest and contain the biggest and the most stars, it is natural to suppose that they are the true cause of the affection in question. The circle and the constellations in it may be seen in the diagram. The so-called 'scattered' stars it is not possible to set down in the same way on the sphere because none of them have an evident permanent position; but if you look up to the sky the point is clear. For in this circle alone are the intervals full of these stars: in the other circles there are obvious gaps.
ὥστ' εἴπερ καὶ περὶ τοῦ φαίνεσθαι κομήτας ἀποδεχόμεθα τὴν αἰτίαν ὡς εἰρημένην μετρίως, καὶ περὶ τοῦ γάλακτος τὸν αὐτὸν ὑποληπτέον τρόπον ἔχειν ὃ γὰρ ἐκεῖ περὶ ἕνα ἐστὶν πάθος ἡ κόμη, τοῦτο περὶ κύκλον τινὰ συμβαίνει γίγνεσθαι τὸ αὐτό, καὶ ἔστιν τὸ γάλα, ὡς εἰπεῖν οἷον ὁριζόμενον, ἡ τοῦ μεγίστου διὰ τὴν ἔκκρισιν κύκλου κόμη. διὸ καθάπερ πρότερον εἴπομεν, οὐ πολλοὶ οὐδὲ πολλάκις γίγνονται κομῆται, διὰ τὸ συνεχῶς ἀποκεκρίσθαι καὶ ἀποκρίνεσθαι καθ' ἑκάστην περίοδον εἰς τοῦτον τὸν τόπον αἰεὶ τὴν τοιαύτην σύστασιν.	90 Hence if we accept the cause assigned for the appearance of comets as plausible we must assume that the same kind of thing holds good of the milky way. For the fringe which in the former case is an affection of a single star here forms in the same way in relation to a whole circle. So if we are to define the milky way we may call it 'a fringe attaching to the greatest circle, and due to the matter secreted'. This, as we said before, explains why there are few comets and why they appear rarely; it is because at each revolution of the heavens this matter has always been and is always being separated off and gathered into this region.
περὶ μὲν οὖν τῶν γιγνομένων ἐν τῷ περὶ τὴν γῆν κόσμῳ τῷ συνεχεῖ ταῖς φοραῖς εἴρηται, περί τε τῆς διαδρομῆς τῶν ἄστρων καὶ τῆς ἐκπιμπραμένης φλογός, ἔτι δὲ περί τε κομητῶν καὶ τοῦ καλουμένου γάλακτος σχεδὸν γάρ εἰσιν τοσαῦτα τὰ πάθη τὰ φαινόμενα περὶ τὸν τόπον τοῦτον.	91 We have now explained the phenomena that occur in that part of the terrestrial world which is continuous with the motions of the heavens, namely, shooting-stars and the burning flame, comets and the milky way, these being the chief affections that appear in that region.

Reprobatis opinionibus aliorum de circulo lacteo, hic ponit propriam opinionem. Et circa hoc duo facit:	86. Having rejected the opinion of others about the milky circle, he now presents his own opinion. About this he does two things:
primo resumit quaedam superius dicta, quae sunt utilia ad propositum manifestandum; secundo manifestat propositum, ibi: quod itaque secundum unum astrorum accidit et cetera.	First, he recalls previous statements useful for explaining the proposition; Secondly, he manifests the proposition, at 88.
Resumit autem duo: primo quidem quod supra dictum est de positione siccae exhalationis, et eius inflammatione. Unde dicit quod vult resumere id quod supra posuit tanquam principium. Dictum est enim supra quod communiter vocatur aer totum hoc quod est intra terram et globum lunarem; huius autem suprema pars, licet non proprie possit dici ignis, quia ignis significat excessum in caliditate, sicut glacies in frigore, tamen illa pars superior aeris habet virtutem ignis, quia est calida et sicca; ita quod, cum aer per motum caelestem disgregatur, talis consistentia exhalationis praedictae segregatur a terra et ab aere inferiori, et elevatur sursum, et ex hoc dicimus apparere stellas cometas.	He recalls two things: first, what was previously said about the location of the dry exhalation and of its kindling [85]. Hence he says that he wants to recall what he previously laid down as a principle. For it has been previously said that everything between earth and the globe of the moon has the common name of "air," while the highest part thereof, although it cannot strictly be called "fire" (because fire denotes a superabundance of heat, just as does ice with respect to cold), yet that upper part of the air does have the virtue of fire, because it is hot and dry — with the result that, when the air is separated by the heavenly motion, a certain consistency of the exhalation already mentioned is collected from the earth and lower air and lifted upward; and we say that it is from this that comet stars appear.
Secundo ibi: tale itaque oportet etc., resumit quod dictum est supra de uno modo apparitionis cometae. Et dicit quod oportet intelligere aliquid simile esse in lacteo circulo, quod fit in cometis, quando cometa non fuerit aliqua exhalatio elevata et ignita per se existens absque aliqua stella, sed fit eius apparitio ab aliqua stellarum fixarum vel errantium, sicut dictum est. Quia tunc apparent cometae propter hoc, quod tales exhalationes elevatae consequuntur motum stellarum quae videntur cometae; sicut etiam solem sequitur talis adunata exhalatio, ex qua, propter repercussionem radiorum, apparet halo, cum aer ad hoc fuerit dispositus.	87. Secondly [86], he recalls what he previously said concerning one of the ways that account for the appearance of a comet. And he says that we should understand in the milky circle something akin to what takes place in comets when the comet is not an exhalation borne aloft and ignited, and existing by itself apart from any star, but is an apparition deriving from one of the fixed or wandering stars, as was said. For in those cases comets appear because such elevated exhalations accompany the course of the stars that appear as comets; just as the sun is accompanied by such a collected exhalation, from which, as a result of reflected rays, a halo appears, when the air is disposed for such.
Deinde cum dicit: quod itaque secundum unum astrorum accidit etc., manifestat propositum, ostendens quae sit causa apparitionis lactei circuli. Et circa hoc tria facit:	88. Then [87] he manifests the proposition, showing what is the cause of the appearance of the milky circle. About this he does three things;
primo proponit causam apparitionis lactei circuli; secundo inducit signum eorum quae dicta sunt, ibi: signum autem etc.; tertio concludit propositum, ibi: quare si quidem et cetera.	First, he proposes the cause of the appearance of the milky circle; Secondly, he introduces a sign to support what he said, at 90; Thirdly, he concludes the proposition, at 92.
Circa primum duo facit. Primo ostendit causam apparitionis lactei circuli. Et dicit quod illud quod accidit in apparitione secundum unam stellam, oportet accipere esse factum circa totum caelum et circa totum motum ipsius: quia rationabile est quod, si motus unius stellae attrahit et circumducit aliquam exhalationem, quod multo magis hoc possit facere motus omnium stellarum; et praecipue in loco illo caeli, ubi apparent frequentissimae stellae et plurimae et maximae.	Regarding the first he does two things. First, he shows the cause of the appearance of the milky circle [87] and says that what happens with respect to the appearance of one star should be understood as happening with respect to the entire heaven and its entire course — because it is reasonable, if the motion of one star attracts and carries an exhalation along, that this should be all the more true of the motion of all the stars, and especially in that region of the heaven where there appears a very large collection of stars, greatest both in number and size.
Secundo ibi: qui quidem igitur animalium etc., ostendit causam quare in hac determinata parte caeli circuli lactei claritas apparet. Et dicit quod circulus animalium, qui dicitur zodiacus, dissolvit adunationem praedictae exhalationis, propter hoc quod per zodiacum movetur sol et alii planetae. Et haec est etiam causa propter quam, ut plurimum, cometae non apparent in zodiaco, sed extra tropicos, ut dictum est.	89. Secondly [88], he shows the cause why it is in that determinate part of the heaven that the brightness of the milky circle appears. And he says that the circle of the animals, called the "Zodiac," dissolves the accumulated mass of the above-mentioned exhalation, because of the fact that the sun and the other planets are moved through the Zodiac. This also explains why, for the most part, comets do not appear in the Zodiac, but outside the tropics, as was said.
Et haec est etiam causa propter quam circa solem et lunam non fit coma: quia videlicet per motum solis et lunae citius disgregatur exhalatio (quam diximus esse causam apparitionis cometae et lactei circuli), quam ut possit adunari ad causandum apparitiones praedictas. Sed iste circulus in quo apparet nobis videntibus lactea claritas, et est unus maximorum circulorum, quia dividit sphaeram per medium; et est sic dispositus secundum situm, ut ex utraque parte multum excedat utrumque tropicum, scilicet hiemalem et aestivum, licet intersecetur a zodiaco. Et etiam hic locus istius circuli est plenus magnis stellis fulgidis, et quae propter frequentiam et spissitudinem vocantur sporadicae, idest seminatae in caelo (quod etiam manifeste oculis videri potest); ita quod propter huiusmodi causam semper in tali parte caeli adunetur exhalatio; quia videlicet in hac parte caeli est efficax virtus stellarum ad attrahendam exhalationem, et non est causa vehemens quae impediat eius adunationem, sicut accidit sub zodiaco circulo. Ista igitur exhalatio adunata sub tali parte caeli, facit ibi videri lacteam claritatem, sicut et exhalatio consequens aliquam stellam, facit ibi videri comam.	Moreover, this also is the cause why no fringe [coma] appears around the sun and moon: namely, because the motions of the sun and moon separate the exhalation (which we have said to cause the appearance of a comet and of the milky circle) faster than it can accumulate to cause these appearances. But that circle in which a milky brightness appears to us observers is both one of the greatest circles (for it divides the sphere in half), and is so located that in both directions it far exceeds both the tropic circles, namely, the winter and the summer one, even though it is intersected by the Zodiac. Moreover, this place of that circle is filled with bright stars so numerous and thick that they are called "sporadic," i.e., sowed in the heaven (this can be observed with the naked eye); as a result, an exhalation is always gathered together in such an area of the heaven, since, namely, there is in this region of the heaven stellar virtue powerful enough to attract the exhalation, and no vehement cause impeding its accumulating, as happens in the zodiacal circle. Accordingly, the exhalation accumulated in that region of the heaven causes a milky brightness to be seen there, just as the exhalation accompanying a star makes a fringe appear.
Deinde cum dicit: signum autem etc., manifestat quod dictum est, per signum: dicens quod signum praedictorum est, quod in ipso lacteo circulo unus eius semicirculus duplatur, et habet amplius de lumine. Cuius causa est, quia in illo semicirculo sunt plures stellae et magis frequentes quam in alio, ac si nulla esset alia causa claritatis apparentis, quam motus astrorum plurimorum frequentium. Quia si in isto circulo apparet claritas in quo plures stellae ponuntur, et in illa eius parte plus apparet in qua sunt stellae plures et magis frequentes, verisimile est multitudinem stellarum esse causam huius apparitionis.	90. Then [89] he shows what he has said with a sign, and says that a sign of the foregoing is that in the milky circle one of its semicircles is doubled and has more light. The reason for this is that in that semicircle there are more stars there and closer together than in the other semicircle, as though there were no other cause of the visible brightness than the movements of a great many clustered stars. For if a brightness appears in that circle in which there are more stars, and if more brightness appears in that section in which the stars are more numerous and closer together, it is reasonable that it is the multitude of stars that causes this appearance.
Quod autem dictum est de isto circulo et de stellis in eo existentibus, potest considerari ex descriptione: quia astrologi describunt totam sphaeram cum stellis in ea existentibus.	What was said of the circle itself, and of the stars existing in it, can be seen from the diagram — since the astronomers have drawn charts of the whole sphere and of the constellations in it.
Exponit autem consequenter quare stellae in circulo lacteo existentes vocantur sporadicae, idest seminatae: quia videlicet sic sunt dispersae per illam partem caeli, quod non contingit eas ordinare sub aliqua figuratione, sicut stellas existentes in aliis partibus caeli; quia unaquaeque earum non habet aliquam determinatam positionem, ut possit ad similitudinem alicuius figurae reduci. Et hoc manifestum est aspicienti in caelo: quia in solo hoc circulo spatia intermedia inter stellas maiores, sunt plena quibusdam parvis stellis; sed in aliis locis caeli manifeste deficiunt stellae, quapropter intermedia apparent vacua a stellis.	91. Then he explains why the stars in the milky circle are called "sporadic," i.e., scattered like seeds: it is because they are scattered through that region of the heaven in such a way that they do not allow being grouped under some figure as do the stars existing in other regions of the heaven, since each of them does not have a fixed position so that they could be reduced into the likeness of some figure. This is plain to anyone looking at the heaven: because it is only in this circle that the areas between the major stars are filled with certain small stars; while in other regions of the heaven stars are manifestly lacking, so that the intervening spaces appear empty of stars.
Deinde cum dicit: quare si quidem etc., concludit ex supradictis suam intentionem. Et dicit quod si causa supra assignata de apparitione cometae, acceptanda est tanquam mediocriter dicta (quia scilicet nullum habet inconveniens manifestum), existimandum est etiam sic se habere de circulo lacteo: quia quod in cometis est coma circa unam stellam, eandem passionem accidit fieri circa quendam circulum. Ita quod lactea claritas, ut ita dicatur quasi definiendo, nihil aliud sit (lactea via) quam coma eiusdem maximi circuli, in caelo apparens propter segregationem, idest elevationem a terra, exhalationis ad illam partem adunatae. Et ideo, sicut prius dictum est, non fiunt multi cometae neque frequenter, quia talis adunatio exhalationis quae elevata est a terra, elevatur secundum unamquamque circulationem, et adunatur maxime in loco lactei circuli; ita quod a lacteo circulo exhalatio superabundans non relinquitur, quae possit esse materia apta ad cometae apparitionem.	92. Then [90] he concludes his intention from the foregoing. And he says that if the cause assigned above of the comet's appearance is accepted as plausible (because it involves no manifest inconsistencies), the same should be accorded this explanation of the milky circle: because what, in the case of comets, is a fringe about one star, is here a corresponding passion affecting some one circle. Thus, the milky clarity, if one were, so to speak, to define it, would be, as the milky way, nothing other than a fringe [coma] of the same greatest circle, appearing in the heaven on account of the "separating," i.e., the lifting from the earth, of an exhalation concentrated in that area. And therefore, as was already stated, many comets are not produced and they do not appear frequently, since such a gathering of the exhalation elevated from the earth is drawn up in accord with each revolution and brought together mostly in the region of the milky circle, in such a way that no surplus exhalation is left over from the milky circle which could be material suitable for the appearance of a comet.
Ultimo autem recapitulat ea quae dicta sunt. Et dicit quod dictum est de his quae fiunt in hoc mundo qui est circa terram, qui scilicet est suppositus generationi et corruptioni, quantum ad illum locum qui est continuus, idest contiguus, motibus caelestibus: scilicet de discursu astrorum, et de ignita flamma, et de cometis et lacteo circulo; quia huiusmodi passiones apparent circa locum istum superiorem.	93. Finally he sums up what has been said [91] and says that we have spoken of the things that take place in the earth-environing world, which is subject, namely, to generation and corruption, as to that region which is "continuous," i.e., contiguous, to the heavenly movements: of the shooting of stars and of the burning flame and of comets and the milky circle, because such passions appear in that upper region.

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Lecture 14 The causes in general of phenomena generated by the moist exhalation in the lower part of the air. Of rain, dew and frost
Chapter 9
περὶ δὲ τοῦ τῇ θέσει μὲν δευτέρου τόπου μετὰ τοῦτον, πρώτου δὲ περὶ τὴν γῆν, λέγωμεν οὗτος γὰρ κοινὸς ὕδατός τε τόπος καὶ ἀέρος καὶ τῶν συμβαινόντων περὶ τὴν ἄνω γένεσιν αὐτοῦ. ληπτέον δὲ καὶ τούτων τὰς ἀρχὰς καὶ τὰς αἰτίας πάντων ὁμοίως.	92 Let us go on to treat of the region which follows next in order after this and which immediately surrounds the earth. It is the region common to water and air, and the processes attending the formation of water above take place in it. We must consider the principles and causes of all these phenomena too as before.
ἡ μὲν οὖν ὡς κινοῦσα καὶ κυρία καὶ πρώτη τῶν ἀρχῶν ὁ κύκλος ἐστίν, ἐν ᾧ φανερῶς ἡ τοῦ ἡλίου φορὰ διακρίνουσα καὶ συγκρίνουσα τῷ γίγνεσθαι πλησίον ἢ πορρώτερον αἰτία τῆς γενέσεως καὶ τῆς φθορᾶς ἐστι.	93 The efficient and chief and first cause is the circle in which the sun moves. For the sun as it approaches or recedes, obviously causes dissipation and condensation and so gives rise to generation and destruction.
μενούσης δὲ τῆς γῆς, τὸ περὶ αὐτὴν ὑγρὸν ὑπὸ τῶν ἀκτίνων καὶ ὑπὸ τῆς ἄλλης τῆς ἄνωθεν θερμότητος ἀτμιδούμενον φέρεται ἄνω	94 Now the earth remains but the moisture surrounding it is made to evaporate by the sun's rays and the other heat from above, and rises.
τῆς δὲ θερμότητος ἀπολιπούσης τῆς ἀναγούσης αὐτό, καὶ τῆς μὲν διασκεδαννυμένης πρὸς τὸν ἄνω τόπον, τῆς δὲ καὶ σβεννυμένης διὰ τὸ μετεωρίζεσθαι πορρώτερον εἰς τὸν ὑπὲρ τῆς γῆς ἀέρα, συνίσταται πάλιν ἡ ἀτμὶς ψυχομένη διά τε τὴν ἀπόλειψιν τοῦ θερμοῦ καὶ τὸν τόπον, καὶ γίγνεται ὕδωρ ἐξ ἀέρος γενόμενον δὲ πάλιν φέρεται πρὸς τὴν γῆν.	95 But when the heat which was raising it leaves it, in part dispersing to the higher region, in part quenched through rising so far into the upper air, then the vapour cools because its heat is gone and because the place is cold, and condenses again and turns from air into water. And after the water has formed it falls down again to the earth.
ἔστι δ' ἡ μὲν ἐξ ὕδατος ἀναθυμίασις ἀτμίς, ἡ δ' ἐξ ἀέρος εἰς ὕδωρ νέφος ὁμίχλη δὲ νεφέλης περίττωμα τῆς εἰς ὕδωρ συγκρίσεως. διὸ σημεῖον μᾶλλόν ἐστιν εὐδίας ἢ ὑδάτων οἷον γάρ ἐστιν ἡ ὁμίχλη νεφέλη ἄγονος.	96 The exhalation of water is vapour: air condensing into water is cloud. Mist is what is left over when a cloud condenses into water, and is therefore rather a sign of fine weather than of rain; for mist might be called a barren cloud.
γίγνεται δὲ κύκλος οὗτος μιμούμενος τὸν τοῦ ἡλίου κύκλον ἅμα γὰρ (347a.) ἐκεῖνος εἰς τὰ πλάγια μεταβάλλει καὶ οὗτος ἄνω καὶ κάτω. δεῖ δὲ νοῆσαι τοῦτον ὥσπερ ποταμὸν ῥέοντα κύκλῳ ἄνω καὶ κάτω, κοινὸν ἀέρος καὶ ὕδατος πλησίον μὲν γὰρ ὄντος τοῦ ἡλίου ὁ τῆς ἀτμίδος ἄνω ῥεῖ ποταμός, ἀφισταμένου δὲ ὁ τοῦ ὕδατος κάτω. καὶ τοῦτ' ἐνδελεχὲς ἐθέλει γίγνεσθαι κατά γε τὴν τάξιν ὥστ' εἴπερ ᾐνίττοντο τὸν ὠκεανὸν οἱ πρότερον, τάχ' ἂν τοῦτον τὸν ποταμὸν λέγοιεν τὸν κύκλῳ ῥέοντα περὶ τὴν γῆν.	97 So we get a circular process that follows the course of the sun. For according as the sun moves to this side or that, the moisture in this process rises or falls. We must think of it as a river flowing up and down in a circle and made up partly of air, partly of water. When the sun is near, the stream of vapour flows upwards; when it recedes, the stream of water flows down: and the order of sequence, at all events, in this process always remains the same. So if 'Oceanus' had some secret meaning in early writers, perhaps they may have meant this river that flows in a circle about the earth.
ἀναγομένου δὲ τοῦ ὑγροῦ αἰεὶ διὰ τὴν τοῦ θερμοῦ δύναμιν καὶ πάλιν φερομένου κάτω διὰ τὴν ψύξιν πρὸς τὴν γῆν, οἰκείως τὰ ὀνόματα τοῖς πάθεσιν κεῖται καί τισιν διαφοραῖς αὐτῶν ὅταν μὲν γὰρ κατὰ μικρὰ φέρηται, ψακάδες, ὅταν δὲ κατὰ μείζω μόρια, ὑετὸς καλεῖται.	98 So the moisture is always raised by the heat and descends to the earth again when it gets cold. These processes and, in some cases, their varieties are distinguished by special names. When the water falls in small drops it is called a drizzle; when the drops are larger it is rain.
Chapter 10
ἐκ δὲ τοῦ καθ' ἡμέραν ἀτμίζοντος ὅσον ἂν μὴ μετεωρισθῇ δι' ὀλιγότητα τοῦ ἀνάγοντος αὐτὸ πυρὸς πρὸς τὸ ἀναγόμενον ὕδωρ, πάλιν καταφερόμενον ὅταν ψυχθῇ νύκτωρ, καλεῖται δρόσος καὶ πάχνη,	99 Some of the vapour that is formed by day does not rise high because the ratio of the fire that is raising it to the water that is being raised is small. When this cools and descends at night it is called dew and hoar-frost.
πάχνη μὲν ὅταν ἡ ἀτμὶς παγῇ πρὶν εἰς ὕδωρ συγκριθῆναι πάλιν (γίγνεται δὲ χειμῶνος, καὶ μᾶλλον ἐν τοῖς χειμερινοῖς τόποις), δρόσος δ' ὅταν συγκριθῇ εἰς ὕδωρ ἡ ἀτμίς, καὶ μήθ' οὕτως ἔχῃ ἡ ἀλέα ὥστε ξηρᾶναι τὸ ἀναχθέν, μήθ' οὕτω ψῦχος ὥστε παγῆναι τὴν ἀτμίδα αὐτὴν διὰ τὸ ἢ τὸν τόπον ἀλεεινότερον ἢ τὴν ὥραν εἶναι γίγνεται γὰρ μᾶλλον ἡ δρόσος ἐν εὐδίᾳ καὶ ἐν τοῖς εὐδιεινοτέροις τόποις, ἡ δὲ πάχνη, καθάπερ εἴρηται, τοὐναντίον δῆλον γὰρ ὡς ἡ ἀτμὶς θερμότερον ὕδατος (ἔχει γὰρ τὸ ἀνάγον ἔτι πῦρ), ὥστε πλείονος ψυχρότητος αὐτὴν πῆξαι.	100 When the vapour is frozen before it has condensed to water again it is hoar-frost; and this appears in winter and is commoner in cold places. It is dew when the vapour has condensed into water and the heat is not so great as to dry up the moisture that has been raised nor the cold sufficient (owing to the warmth of the climate or season) for the vapour itself to freeze. For dew is more commonly found when the season or the place is warm, whereas the opposite, as has been said, is the case with hoar-frost. For obviously vapour is warmer than water, having still the fire that raised it: consequently more cold is needed to freeze it.
γίγνεται δ' ἄμφω αἰθρίας τε καὶ νηνεμίας οὔτε γὰρ ἀναχθήσεται μὴ οὔσης αἰθρίας, οὔτε συστῆναι δύναιτ' ἂν ἀνέμου πνέοντος. σημεῖον δ' ὅτι γίγνεται ταῦτα διὰ τὸ μὴ πόρρω μετεωρίζεσθαι τὴν ἀτμίδα ἐν γὰρ τοῖς ὄρεσιν οὐ γίγνεται πάχνη.	101 Both dew and hoar-frost are found when the sky is clear and there is no wind. For the vapour could not be raised unless the sky were clear, and if a wind were blowing it could not condense.
αἰτία δὲ μία μὲν αὕτη, ὅτι ἀνάγεται ἐκ τῶν κοίλων καὶ ἐφύδρων τόπων, ὥστε καθάπερ φορτίον φέρουσα πλέον ἡ ἀνάγουσα θερμότης ἢ καθ' ἑαυτὴν οὐ δύναται μετεωρίζειν ἐπὶ πολὺν τόπον αὐτὸ τοῦ ὕψους, ἀλλ' ἐγγὺς ἀφίησι πάλιν ἑτέρα δ' ὅτι καὶ ῥεῖ μάλιστα ὁ ἀὴρ ῥέων ἐν τοῖς ὑψηλοῖς, ὃς διαλύει τὴν σύστασιν τὴν τοιαύτην.	102 The fact that hoar-frost is not found on mountains contributes to prove that these phenomena occur because the vapour does not rise high. One reason for this is that it rises from hollow and watery places, so that the heat that is raising it, bearing as it were too heavy a burden cannot lift it to a great height but soon lets it fall again. A second reason is that the motion of the air is more pronounced at a height, and this dissolves a gathering of this kind.
γίγνεται δ' ἡ δρόσος πανταχοῦ νοτίοις, οὐ βορείοις, πλὴν ἐν τῷ Πόντῳ. ἐκεῖ δὲ τοὐναντίον βορείοις μὲν γὰρ γίγνεται, νοτίοις δ' οὐ (347b.) γίγνεται.	103 Everywhere, except in Pontus, dew is found with south winds and not with north winds. There the opposite is the case and it is found with north winds and not with south.
αἴτιον δ' ὁμοίως ὥσπερ ὅτι εὐδίας μὲν γίγνεται, χειμῶνος δ' οὔ ὁ μὲν γὰρ νότος εὐδίαν ποιεῖ, ὁ δὲ βορέας χειμῶνα ψυχρὸς γάρ, ὥστ' ἐκ τοῦ χειμῶνος τῆς ἀναθυμιάσεως σβέννυσι τὴν θερμότητα.	104 The reason is the same as that which explains why dew is found in warm weather and not in cold. For the south wind brings warm, and the north, wintry weather. For the north wind is cold and so quenches the heat of the evaporation.
ἐν δὲ τῷ Πόντῳ ὁ μὲν νότος οὐχ οὕτως ποιεῖ εὐδίαν ὥστε γίγνεσθαι ἀτμίδα, ὁ δὲ βορέας διὰ τὴν ψυχρότητα ἀντιπεριιστὰς τὸ θερμὸν ἀθροίζει, ὥστε πλέον ἀτμίζει μᾶλλον. πολλάκις δὲ τοῦτο καὶ ἐν τοῖς ἔξω τόποις ἰδεῖν γιγνόμενον ἔστιν ἀτμίζει γὰρ τὰ φρέατα βορείοις μᾶλλον ἢ νοτίοις ἀλλὰ τὰ μὲν βόρεια σβέννυσιν πρὶν συστῆναί τι πλῆθος, ἐν δὲ τοῖς νοτίοις ἐᾶται ἀθροίζεσθαι ἡ ἀναθυμίασις. αὐτὸ δὲ τὸ ὕδωρ οὐ πήγνυται, καθάπερ ἐν τῷ περὶ τὰ νέφη τόπῳ.	105 But in Pontus the south wind does not bring warmth enough to cause evaporation, whereas the coldness of the north wind concentrates the heat by a sort of recoil, so that there is more evaporation and not less. This is a thing which we can often observe in other places too. Wells, for instance, give off more vapour in a north than in a south wind. Only the north winds quench the heat before any considerable quantity of vapour has gathered, while in a south wind the evaporation is allowed to accumulate. Water, once formed, does not freeze on the surface of the earth, in the way that it does in the region of the clouds.

Postquam philosophus determinavit de his quae causantur ex exhalatione sicca ad supremum locum aeris elevata, hic determinat de his quae causantur ex exhalatione humida.	94. After determining concerning phenomena caused from the hot exhalation lifted to the highest place of the air, the Philosopher here determines about phenomena caused from the moist exhalation.
Et primo de his quae causantur ex exhalatione humida super terram; secundo de his quae causantur ex exhalatione humida in terra, ibi: de ventis autem et cetera.	First, about phenomena caused above the earth from the moist exhalation; Secondly, about those caused on the earth from the moist exhalation (L. 16).
Circa primum duo facit. Primo ostendit de quo est intentio: dicens quod nunc dicendum est de his quae fiunt in loco qui secundum situm, descendendo, est secundus post locum supremum aeris, in quo fiunt ea quae dicta sunt, sed ascendendo est primus, immediatus circa terram; quae inferior pars aeris est. Iste enim locus est communis et aquae et aeri: quia in eo aer est secundum naturalem ordinem elementorum, et aqua ex vaporibus elevatis ibi generatur. Unde non solum est communis aquae et aeri, sed etiam eis quae accidunt circa generationem ipsius aquae et aeris, quae fiunt superius dum aqua resolvitur in vapores, qui pertinent ad naturam aeris, et vapores congregantur in aquam. Ostendit etiam modum determinandi de istis, dicens quod debemus sumere primo principia communia et causas omnium horum accidentium.	95. Regarding the first he does two things: first, he shows what his intention concerns [92] and says that we must now discuss the things which come to be in the region which, going downwards, is the second after the uppermost region of the air (where the phenomena already discussed take place), but which, going upward, is first, i.e., the region immediately around the earth: this region is the lower region of air. It is the region common both to water and to air; because in it air exists according to the natural order of the elements, and water is generated there from vapors borne aloft. Hence not only is it common to water and air, but also to the phenomena attending the generation of that water and air. These generations take place on high, when water is resolved into vapors (which pertain to the nature of air) and vapors are gathered into water. He also indicates the method for determining these matters and says that we should first take the common principles and causes of all these things that happen.
Secundo ibi: quod quidem igitur etc., determinat propositum.	96. Secondly [93] he determines the proposition.
Et primo ponit ea quae communiter pertinent ad causam omnium huiusmodi passionum; secundo determinat de singulis passionibus, ostendens differentiam inter eas, ibi: elevato autem humido et cetera.	First, he posits what pertains commonly to the cause of all passions of this kind; Secondly, he determines concerning each of them separately, showing wherein they differ, at 101.
Circa primum tria facit. Primo ponit causam effectivam harum passionum. Et dicit quod illud quod est causa sicut movens et principale et primum principium omnium harum passionum, est circulus zodiacus, in quo manifeste movetur sol, qui et disgregat resolvendo vapores a terra, et congregat eos per suam absentiam: frigore enim invalescente in aere per absentiam solis, nubes condensantur in aquam. Et ideo subiungit quod ex hoc quod quandoque fit prope nos, quandoque autem elongatur a nobis, existit causa generationis et corruptionis. Fit prope autem nobis secundum proprium motum, quando accedit ad signa Septentrionalia: elongatur autem a nobis, dum moratur in signis meridionalibus.	About the first he does three things: first, he sets down the efficient cause of these passions [93] and says that all these passions have as their cause, in the sense of the movent, and primary, and first principle, the circle of the Zodiac in which the sun clearly moves, which both separates the vapors, by resolving them from earth, and unites them by its absence: for when coldness increases in the air on account of the sun's absence, clouds are condensed into water. Accordingly he adds that from its being at one time near us, and at another time away from us, the sun is the cause of generation and corruption. It gets near us, when by its own motion it approaches the northern signs; it is moved away from us, when it tarries in the southern signs.
Secundo ibi: manente autem terra etc., ostendit causam materialem harum passionum. Et dicit quod, cum terra quiescat in medio, illud humidum aqueum quod est circa ipsam, tum a radiis solis tum ab alia caliditate quae est a superioribus corporibus, resolvitur in vaporem, et sic subtiliatum per virtutem calidi sursum fertur.	97. Secondly [94], he shows the material cause of these passions and says that, since the earth is at rest in the center, the aqueous humor surrounding it is, both through the agency of the sun's rays and through other heat from the higher bodies, resolved into vapor and, being thus refined by the virtue of the heat, borne aloft.
Tertio ibi: caliditate autem etc., ostendit modum generationis horum de quibus intendit. Et circa hoc tria facit. Primo ponit in communi modum generationis harum passionum. Et dicit quod vapor qui sursum fertur per virtutem caloris, deseritur a caliditate quae sursum eum ferebat. Quod quidem contingit dupliciter: uno modo per hoc quod id quod erat subtilius et calidius in vapore, elevatur ulterius ad superiorem locum exhalationis siccae, et sic residua pars vaporis remanet frigida; alio modo per hoc quod calor qui est in vapore extinguitur, propter hoc quod longe elevatur a terra in aere qui est supra terram, ubi deficit calor propter hoc quod radii reverberati a terra in immensum sparguntur, ut supra dictum est. Sic igitur deficiente calore calefaciente et elevante vaporem aqueum, vapor aqueus redit ad suam naturam, coadunante etiam frigiditate loci; et sic infrigidatur, et infrigidatus inspissatur, et inspissatus cadit ad terram.	98. Thirdly [95], he shows the way in which the things under discussion are generated. About this he does three things: first, he states in general the way these passions are generated and says that the vapor borne aloft by the power of the heat is abandoned by the heat which bore it aloft. This happens in two ways: in one way by the fact that the finer and warmer elements in the vapor are raised higher still, to the upper region of the dry exhalation — consequently, the portion of vapor left behind remains cold; in another way by the fact that the heat in the vapor is quenched by having been lifted far from the earth, in the air above the earth where heat is feeble on account of the rays reflected from the earth being scattered far apart, as was stated above. Therefore, when the heat which warmed and elevated the moist vapor runs out, this vapor returns to its nature, with the coldness of the region condensing it; thus it becomes cool,-and after being cooled, it is thickened, and once thickened, it falls to earth.
Secundo ibi: est autem quae quidem etc., ostendit quid sit medium in praedictis transmutationibus. In prima enim transmutatione, secundum quam aqua subtiliatur et elevatur, medium est vapor: nam ipsa exhalatio resoluta ab aqua vocatur vapor, qui est medius inter aerem et aquam. In illa autem transmutatione secundum quam aer condensatur in aquam, medium est nubes, quae est via generationis aquae. Sed cum nubes condensatur in aquam, id quod est residuum de nube, quod scilicet in aquam condensari non potuit, est caligo nebulae. Et ideo nebula magis est signum serenitatis quam pluviae: quia nebula est quasi quaedam nubes sterilis, idest sine pluvia, quae est naturalis effectus nubis. Contingit tamen aliquando nebulam elevari in ipsa exhalatione vaporum, antequam condensentur in nubem perfecte: et tunc nebula potest esse signum pluviae.	99. Secondly [96] he shows what intermediates are involved in these transmutations. In the first transmutation, in which water is subtilized and raised up, the intermediate is vapor: for the very exhalation resolved from the water is called "vapor," which is intermediate between air and water. In that transmutation in which air is condensed into water, the medium is a cloud, which is a step toward the generation of water. But when the cloud is condensed into water, that which is left over in the cloud, i.e., whatever could not be condensed into water, is called the fog of mist. That is why mist is more a sign of clear than of rainy weather: for mist is, as it were, a "barren" cloud, i.e., devoid of rain, which is the natural effect of a cloud. However it sometimes happens that mist is carried up along with the vaporous exhalations before they are perfectly condensed into a cloud — and then mist can be a sign of rain.
Tertio ibi: fit autem circulus iste etc., ostendit quomodo in praedictis transmutationibus representatur similitudo primae causae moventis, scilicet circulationis solis. Attenditur enim quaedam circulatio in praedictis transmutationibus, dum aqua resolvitur in vapores, qui condensantur in nubes, et nubes in aquam, quae cadit in terram. Dicit ergo quod ista circularis transmutatio imitatur circularem motum solis: sol enim permutatur ad diversas partes caeli, puta ad Septentrionem et meridiem, et circulatio ista completur in hoc quod vapores ascendunt sursum et descendunt deorsum. Sed oportet intelligere quod iste fluxus vaporum ascendentium et descendentium, sit quasi quidam fluvius circularis communis aeri et aquae: nam quod aqua resolvitur in vaporem, ad aerem attinet, quod autem nubes in aquam condensantur, ad aquam. Cum ergo sol prope existit, iste fluvius vaporum ascendit sursum; cum autem elongatur sol, descendit deorsum; et hoc indesinenter fit secundum ordinem praedictum. Unde concludit quod forte antiqui dicentes Oceanum esse quendam fluvium circumdantem terram, occulte loquebantur de hoc fluvio, qui circulariter fluit circa terram, ut dictum est.	100. Thirdly [97], he shows how the above-mentioned transmutations bear an analogy to the first movent cause, i.e., to the circling of the sun. For a certain circling is discernible in the above-mentioned transmutations, as water is refined into vapors which are condensed into clouds, and the clouds into water, which falls to earth. He says therefore that this circular transmutation imitates the circular movement of the sun — for the sun is changed to diverse parts of the heaven (for example, to the north and to the south); and that cycle is completed in the fact that vapors ascend upwards and descend downwards. But we should understand this flow of ascending and descending vapors as a certain circular stream common to air and water: for the resolving of water into vapor pertains to the air, while the condensing of clouds into water pertains to the water. When, therefore, the sun is near, this river of vapors flows upward; when the sun is away, it flows downward; and this goes on without interruption in the order described. From this he concludes that perhaps the ancients, in speaking of Oceanus as a certain river surrounding the earth, were cryptically speaking of this river, which, as was said, flows circularly around the earth.
Deinde cum dicit: elevato autem humido etc., determinat de praedictis passionibus in speciali, ostendendo differentias earum adinvicem. Et dividitur in duas partes:	101. Then at [98] he discusses the foregoing passions in detail, by pointing out their mutual differences. And it is divided into two parts:
in prima determinat de generatione illorum quae manifestiorem habent causam; in secunda de generatione grandinis, circa quam est maior difficultas, ibi: ipsa autem aqua et cetera.	In the first he determines about the generation of those phenomena whose cause is quite plain; In the second about the generation of hail, concerning which there is greater difficulty (L. 15).
Circa primum duo facit. Primo determinat de pluviis: dicens quod cum humidum aqueum elevatur ex virtute calidi, et iterum fertur deorsum propter infrigidationem, secundum quasdam differentias, huiusmodi passionibus aeris diversa nomina imponuntur. Quia quando per modicas partes vapores inspissati in aquam cadunt, tunc dicuntur psecades, idest guttae, sicut aliquando contingit quod parvae guttae decidunt: quando vero secundum maiores partes decidunt guttae ex vaporibus generatae, vocatur pluvia.	102. About the first he does two things: first, he determines about rain [98] and says that when watery moisture is elevated through the power of heat and is again brought down on account of cooling, different names, based on varying characteristics, are given to these passions of air. For when the vapors condensed into water in small parts fall, then they are called "psecades," i.e., drops, as occasionally happens, when small drops fall; but when the drops of a larger size generated from the vapors fall, this is called "rain."
Secundo ibi: ex eo autem quod de die etc., determinat de rore et pruina. Et circa hoc tria facit. Primo determinat modum generationis eorum. Et dicit quod ros et pruina contingunt ex hoc quod de die, sole existente super terram, aliquid evaporat ex humido aqueo propter solis calorem; quod quidem evaporatum non multum suspenditur vel elevatur super terram, propter hoc quod ignis, idest calor elevans huiusmodi vaporem, est parvus in comparatione ad humorem aqueum qui elevatur. Et ita, cum de nocte infrigidatus fuerit aer, inspissatur ille vapor elevatus de die, et cadit in terram, et vocatur ros vel pruina: ut ita se habeat accessus solis et recessus secundum motum diurnum ad generationem roris et pruinae, secundum quod se habet ad generationem pluviae secundum motum proprium, secundum quod accedit et recedit in aestate et hieme.	103. Secondly [99], he determines about dew and frost. First, he determines the manner in which they are generated. And he says that they arise from the fact that, when the sun is above the earth in daytime, something evaporates from the watery moisture because of the sun's heat, but this evaporation is not suspended or raised very high above the earth, for the simple reason that the "fire," i.e., the heat raising this vapor, is slight in comparison with the watery moisture elevated. Consequently, when the air cools at night, the vapor elevated during the day condenses and falls to earth and is called "dew" or "frost." The approach and departure of the sun in its diurnal course has the same relation to the generation of dew and frost as, in the generation of rain, its proper motion has according as it approaches and departs in summer and winter.
Secundo ibi: pruina quidem etc., ostendit differentiam eorum: dicens quod pruina fit, quando vapor prius congelatur quam condensetur in aquam; et propter hoc fit in hieme et in hiemalibus locis, idest in frigidis locis. Sed ros fit, quando vapor inspissatur in aquam, et neque est tantus aestus quod vapor elevatus desiccetur, neque est tantum frigus quod vapor congeletur. Et ideo oportet quod sit aut in tempore aut in loco calido: quia ros semper fit in tempore temperato et in locis temperatis, sed pruina, sicut dictum est, fit in tempore et loco magis frigidis. Cum enim vapor sit calidior aqua, quia adhuc est in eo aliquid de calore elevante, maior frigiditas requiritur ad congelationem vaporis quam aquae; et sic pruina nunquam fit nisi in magno frigore.	104. Secondly [100], he points out their difference and says that frost occurs when the vapor is frozen before it is condensed into water: for this reason it occurs in winter and in "wintry," i.e., frigid, places. But dew occurs when the vapor is thickened into water and there is neither enough heat to dry out the vapor that has been raised, nor enough cold for the vapor to freeze. Hence dew must occur either during warm seasons or in warm places: because dew occurs always in temperate times or temperate places, but frost in times and places that are colder, as has been said. For since vapor is warmer than water (because some of the heat raising it is still in it) more cold is needed to freeze vapor than to freeze water: as a result, frost never occurs except where there is much cold.
Deinde cum dicit: fiunt autem ambo etc., ostendit qualiter existente aere disposito, fit ros et pruina.	105. Then [101] he shows the conditions of disposed air under which dew and frost occur.
Et primo ostendit hoc communiter quantum ad utrumque; secundo specialiter de rore, ibi: fit autem ros ubique et cetera.	First, he shows this generally as to both, at 105; Secondly, specially for dew, at 107.
Circa primum duo facit:	About the first he does two things:
primo ostendit quod proponit; secundo ponit quoddam signum praedictorum, ibi: signum autem et cetera.	First, he shows what he is proposing, at 105; Secondly, he gives a sign of the aforesaid, at 106.
Dicit ergo primo quod tam ros quam pruina fiunt cum aer fuerit serenus absque nubibus et pluvia, et tranquillus absque vento. Quia si non sit serenus, non possunt elevari vapores de die, propter defectum caloris: si autem non fuerit tranquillitas, vento flante, non poterunt vapores condensari, ut generetur ros; nam ventus, commovendo aerem, impedit congregationem vaporum.	He says therefore first [101], that both dew and frost occur when the air is clear, without clouds and rain, and calm, without wind. Because if it is not clear, vapors cannot be lifted up during the day due to the lack of sufficient heat: if it is not calm, but windy, the vapors could not be condensed to form dew — for the wind, in agitating the air, prevents the vapors from massing together.
Deinde cum dicit: signum autem etc., manifestat per signum quod supra posuerat de generatione roris et pruinae. Et dicit quod signum huius quod ros et pruina causentur ex hoc quod vapor non longe elevatur a terra, est hoc quod in montibus non fit pruina, cum tamen ibi magis videatur fieri propter loci frigiditatem. Huius ergo sunt duae causae. Una quidem, quia vapor ex quo generatur ros et pruina, elevatur ex locis infimis et humefactis, ex quibus multi vapores generantur et elevantur: unde caliditas quae eos elevavit, non potuit elevare eos ad multam altitudinem, quasi portans onus quod excedit suam virtutem; sed prope loca infima dimittit calor vapores, et cadit ros et pruina. Unde in montibus altis pruina esse non potest. Secunda autem causa est, quia sicut supra dictum est, aer superior excedens montes, fluit quasi tractus ex motu caeli; et ideo suo fluxu dissolvit huiusmodi adunationem vaporum, quae est causa roris et pruinae. Plus autem de motu requiritur ad multam materiam vaporosam disgregandam, quam disgregandam parvam: materia autem pluviae et nivis est multa, materia autem roris et pruinae est pauca simpliciter, licet sit multa in comparatione ad calorem parvum elevantem ipsam: unde in montibus altissimis, propter maiorem fluxum aeris, neque pluvia neque ros neque pruina cadit; in montibus autem non ita altis cadit pluvia et nix, propter minorem fluxum, non autem ros et pruina.	106. Then [102] he gives a sign to support what he posited earlier about generation of dew and frost. And he says that a sign of the fact that dew and frost are caused by the fact that vapor is not lifted far above the earth is that frost does not appear on mountains, whereas it would seem that, on account of the cold there present, it should appear there even more. There are two reasons for this: First, because the vapor from which dew and frost are generated is raised from low, moist, places, from which many vapors are generated and lifted up: hence the heat which elevates them, bearing, as it were, a burden too much for its power, cannot raise them to a very great height; hence, while still near the lowest places, the heat leaves the vapors, and dew and frost fall. That is why frost cannot form on high mountains. The second cause is that, as previously stated, the upper air above the mountains flows along, as though carried by the course of the heaven; and therefore, by its flowing it dissolves such gatherings of vapor that cause dew and frost. Now, more motion is needed for scattering large amounts of vaporous matter than small amounts: but the matter of rain and snow coalesces in large amounts, whereas the matter of dew and frost is, absolutely speaking, small, although it is large in relation to the small amount of heat elevating it: hence neither rain nor dew nor frost fall on the highest mountains, because of the greater flow of air; but on mountains that are not so lofty, rain and snow, but no dew or frost, fall, because of the lesser flow of air.
Deinde cum dicit: fit autem ros ubique etc., ostendit specialiter de rore quali dispositione fiat. Et circa hoc tria facit. Primo proponit veritatem: dicens quod ros fit in omnibus locis, flantibus Australibus ventis, non tamen ita validis quod impediant congregationem vaporum. Non autem fit flantibus borealibus ventis, nisi in regione Ponti, quae est frigidissima: ibi enim contrarie accidit, nam tempore boreali fit ros, non autem tempore Australi.	107. Then [103] he shows under what circumstances dew in particular occurs. About this he does three things: first, he proposes a truth and says that dew forms in all places with south winds that are not strong enough to prevent vapors from gathering. It does not form with the blowing of the north wind except in the region of Pontus, which is very cold: there the opposite takes place, for dew forms there with northerly weather but not with southerly weather.
Secundo ibi: causa autem similiter etc., assignat causam eius quod communiter accidit. Et dicit quod causa huius est similis ei quod dictum est: quia scilicet ros fit in tempore temperato, sed non fit in hieme, idest in tempore valde frigido. Et rationem similitudinis ostendit: quia Auster facit temperiem, sed Boreas facit hiemem et frigus, est enim frigidus; et ideo ex hieme, idest ex frigiditate, extinguit caliditatem exhalationis, ut scilicet non possint vapores elevari ad generationem roris.	108. Secondly [104], he assigns the cause of what generally happens and says that the cause of this is akin to what has been said: namely, that dew forms in temperate times but not in "winter," i.e., in very cold times. And he shows the point of similarity: the south wind brings mildness, but the north wind winter and cold, for it is a cold wind; and therefore, because of the "winter," i.e., because of the coldness, the warmth is extinguished from exhalations, and, as a result, the vapors cannot be elevated for dew to be formed.
Tertio ibi: in Ponto autem etc., assignat causam eius quod accidit in Ponto. Et est quod ibi, propter magnam frigiditatem, Auster non sufficit ad facere tantam temperiem quae sufficiat ad elevationem vaporis; et ideo tempore Australi ibi non fit ros. Sed Boreas, propter suam frigiditatem, congregat calidum quod est in locis humectis, antiperistasim faciens, idest cum quadam contrarietate circumstans calidum: cum enim frigidum circumstat calidum, si non omnino possit extinguere ipsum, congregat illud. Et sic ex congregatione calidi vigoratur effectus eius, et ideo magis resolvitur vapor.	109. Thirdly [105], he assigns the cause of what happens in Pontus. The reason is that, because of the great cold there, the south wind is unable to produce sufficient mildness for vapors to be elevated: therefore no dew forms there during the time of the south wind. But the north wind, because of its coldness, collects the warm matter existing in damp places, "making a kind of anti-surrounding," i.e., by surrounding the warm matter with a certain contrariety — for when cold matter surrounds warm matter, if the former cannot completely quench the latter, it concentrates it. Thus, by the concentration of the hot, its effect is strengthened — and, as a result, more vapor is resolved.
Et hoc non tantum in Ponto accidit, sed etiam in aliis locis frequenter videtur factum: quia putei magis vaporant flantibus ventis borealibus quam Australibus, propter calorem congregatum interius ex frigore circumstante. Sed tamen in aliis locis frigiditas Boreae extinguit caliditatem vaporum, antequam aliqua multitudo possit adunari ad generationem roris: sed quando fiunt venti Australes, non impeditur congregatio vaporum ut generetur ros. Sed in Ponto etiam aliquando propter Boream extinguitur calor vaporum, et impeditur eorum elevatio: sed aliquando, propter multitudinem frigoris, multum de calido includitur intra terram, et fit multa exhalatio vaporum; ita quod ad modicum tempus resistit frigiditati aeris, donec congregetur tantum quod sufficiat ad generationem roris.	This occurs not only in Pontus but is frequently observed in other places: wells evaporate more with a north wind than with a south wind, because of the heat trapped in them by the surrounding cold. However, in other places the coldness of the north wind quenches the vapor's heat before any can be concentrated in amounts large enough to generate dew; but when there are south winds, they do not impede the accumulation of vapors needed for generating dew. Even in Pontus there are times when, because of the north wind, the heat of the vapors is quenched and, therefore, do not rise; but sometimes, because of the greatness of the cold, much warmth is enclosed within the earth and a large amount of vaporous exhalation forms, in such a way that, for a brief time, it resists the air's coldness, but only long enough for an amount sufficient for the generation of dew to be accumulated.

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Lecture 15 On the place of the generation of hail and snow
Chapter 11
ἐκεῖθεν γὰρ τρία φοιτᾷ σώματα συνιστάμενα διὰ τὴν ψύξιν, ὕδωρ καὶ χιὼν καὶ χάλαζα. τούτων δὲ τὰ μὲν δύο ἀνάλογον καὶ διὰ τὰς αὐτὰς αἰτίας γίγνεται τοῖς κάτω, διαφέροντα τῷ μᾶλλον καὶ ἧττον καὶ πλήθει καὶ ὀλιγότητι χιὼν γὰρ καὶ πάχνη ταὐτόν, καὶ ὑετὸς καὶ δρόσος, ἀλλὰ τὸ μὲν πολὺ τὸ δ' ὀλίγον. ὁ μὲν γὰρ ὑετὸς ἐκ πολλῆς ἀτμίδος γίγνεται ψυχομένης τούτου δ' αἴτιον ὅ τε τόπος πολὺς καὶ ὁ χρόνος ὤν, ἐν ᾧ συλλέγεται καὶ ἐξ οὗ. τὸ δ' ὀλίγον ἡ δρόσος ἐφήμερος γὰρ ἡ σύστασις καὶ ὁ τόπος μικρός δηλοῖ τε ἥ τε γένεσις οὖσα ταχεῖα καὶ βραχὺ τὸ πλῆθος. ὁμοίως δὲ καὶ πάχνη καὶ χιών ὅταν γὰρ παγῇ τὸ νέφος, χιών ἐστιν, ὅταν δ' ἡ ἀτμίς, πάχνη. διὸ ἢ ὥρας ἢ χώρας ἐστὶν σημεῖον ψυχρᾶς οὐ γὰρ ἂν ἐπήγνυτο ἔτι πολλῆς ἐνούσης θερμότητος, εἰ μὴ ἐπεκράτει τὸ ψῦχος ἐν γὰρ τῷ νέφει ἔτι ἔνεστιν πολὺ θερμὸν τὸ ὑπόλοιπον τοῦ ἐξατμίσαντος ἐκ τῆς γῆς τὸ ὑγρὸν πυρός. χάλαζα δ' ἐκεῖ μὲν γίγνεται, ἐν δὲ τῷ πλησίον τῆς γῆς ἀτμίζοντι τοῦτ' ἐκλείπει καθάπερ γὰρ εἴπομεν, ὡς μὲν ἐκεῖ χιών, ἐνταῦθα γίγνεται πάχνη, ὡς δ' ἐκεῖ ὑετός, ἐνταῦθα δρόσος ὡς δ' ἐκεῖ χάλαζα, ἐνταῦθα οὐκ ἀνταποδίδωσι τὸ ὅμοιον. τὸ δ' αἴτιον εἰποῦσι περὶ χαλάζης ἔσται δῆλον.	106 From the latter there fall three bodies condensed by cold, namely rain, snow, hail. Two of these correspond to the phenomena on the lower level and are due to the same causes, differing from them only in degree and quantity. Snow and hoar-frost are one and the same thing, and so are rain and dew: only there is a great deal of the former and little of the latter. For rain is due to the cooling of a great amount of vapour, for the region from which and the time during which the vapour is collected are considerable. But of dew there is little: for the vapour collects for it in a single day and from a small area, as its quick formation and scanty quantity show. The relation of hoar-frost and snow is the same: when cloud freezes there is snow, when vapour freezes there is hoar-frost. Hence snow is a sign of a cold season or country. For a great deal of heat is still present and unless the cold were overpowering it the cloud would not freeze. For there still survives in it a great deal of the heat which caused the moisture to rise as vapour from the earth. Hail on the other hand is found in the upper region, but the corresponding phenomenon in the vaporous region near the earth is lacking. For, as we said, to snow in the upper region corresponds hoar-frost in the lower, and to rain in the upper region, dew in the lower. But there is nothing here to correspond to hail in the upper region. Why this is so will be clear when we have explained the nature of hail.
Chapter 12
δεῖ δὲ λαβεῖν ἅμα καὶ τὰ συμβαίνοντα περὶ τὴν γένεσιν αὐτῆς, τά τε μὴ πλανῶντα καὶ τὰ δοκοῦντ' εἶναι παράλογα. ἔστι μὲν γὰρ ἡ χάλαζα κρύσταλλος, πήγνυται δὲ τὸ ὕδωρ τοῦ χειμῶνος αἱ δὲ χάλαζαι γίγνονται ἔαρος μὲν (348a.) καὶ μετοπώρου μάλιστα, εἶτα δὲ καὶ τῆς ὀπώρας, χειμῶνος δ' ὀλιγάκις, καὶ ὅταν ἧττον ᾖ ψῦχος. καὶ ὅλως δὲ γίγνονται χάλαζαι μὲν ἐν τοῖς εὐδιεινοτέροις τόποις, αἱ δὲ χιόνες ἐν τοῖς ψυχροτέροις.	107 But we must go on to collect the facts bearing on the origin of it, both those which raise no difficulties and those which seem paradoxical. Hail is ice, and water freezes in winter; yet hailstorms occur chiefly in spring and autumn and less often in the late summer, but rarely in winter and then only when the cold is less intense. And in general hailstorms occur in warmer, and snow in colder places.
ἄτοπον δὲ καὶ τὸ πήγνυσθαι ὕδωρ ἐν τῷ ἄνω τόπῳ οὔτε γὰρ παγῆναι δυνατὸν πρὶν γενέσθαι ὕδωρ, οὔτε τὸ ὕδωρ οὐδένα χρόνον οἷόν τε μένειν μετέωρον ὄν.	108 Again, there is a difficulty about water freezing in the upper region. It cannot have frozen before becoming water: and water cannot remain suspended in the air for any space of time.
ἀλλὰ μὴν οὐδ' ὥσπερ αἱ ψακάδες ἄνω μὲν ὀχοῦνται διὰ μικρότητα, ἐνδιατρίψασαι δ' ἐπὶ τοῦ ἀέρος, ὥσπερ καὶ ἐπὶ τοῦ ὕδατος γῆ καὶ χρυσὸς διὰ μικρομέρειαν πολλάκις ἐπιπλέουσιν, οὕτως ἐπὶ τοῦ ἀέρος τὸ ὕδωρ, συνελθόντων δὲ πολλῶν μικρῶν μεγάλαι καταφέρονται ψακάδες	109 Nor can we say that the case is like that of particles of moisture which are carried up owing to their small size and rest on the iar (the water swimming on the air just as small particles of earth and gold often swim on water). In that case large drops are formed by the union of many small, and so fall down.
τοῦτο γὰρ οὐκ ἐνδέχεται γενέσθαι ἐπὶ τῆς χαλάζης οὐ γὰρ συμφύεται τὰ πεπηγότα ὥσπερ τὰ ὑγρά. δῆλον οὖν ὅτι ἄνω τοσοῦτον ὕδωρ ἔμεινεν οὐ γὰρ ἂν ἐπάγη τοσοῦτον.	110 This cannot take place in the case of hail, since solid bodies cannot coalesce like liquid ones. Clearly then drops of that size were suspended in the air or else they could not have been so large when frozen.
τοῖς μὲν οὖν δοκεῖ τοῦ πάθους αἴτιον εἶναι τούτου καὶ τῆς γενέσεως, ὅταν ἀπωσθῇ τὸ νέφος εἰς τὸν ἄνω τόπον μᾶλλον ὄντα ψυχρὸν διὰ τὸ λήγειν ἐκεῖ τὰς ἀπὸ τῆς γῆς τῶν ἀκτίνων ἀνακλάσεις, ἐλθὸν δ' ἐκεῖ πήγνυσθαι τὸ ὕδωρ διὸ καὶ θέρους μᾶλλον καὶ ἐν ταῖς ἀλεειναῖς χώραις γίγνεσθαι τὰς χαλάζας, ὅτι ἐπὶ πλέον τὸ θερμὸν ἀνωθεῖ ἀπὸ τῆς γῆς τὰς νεφέλας.	111 Some think that the cause and origin of hail is this. The cloud is thrust up into the upper atmosphere, which is colder because the reflection of the sun's rays from the earth ceases there, and upon its arrival there the water freezes. They think that this explains why hailstorms are commoner in summer and in warm countries; the heat is greater and it thrusts the clouds further up from the earth.
συμβαίνει δ' ἐν τοῖς σφόδρα ὑψηλοῖς ἥκιστα γίγνεσθαι χάλαζαν καίτοι ἔδει, ὥσπερ καὶ τὴν χιόνα ὁρῶμεν ἐπὶ τοῖς ὑψηλοῖς μάλιστα γιγνομένην.	112 But the fact is that hail does not occur at all at a great height: yet it ought to do so, on their theory, just as we see that snow falls most on high mountains.
ἔτι δὲ πολλάκις ὦπται νέφη φερόμενα σὺν ψόφῳ πολλῷ παρ' αὐτὴν τὴν γῆν, ὥστε φοβερὸν εἶναι τοῖς ἀκούουσιν καὶ ὁρῶσιν ὡς ἐσομένου τινὸς μείζονος. ὁτὲ δὲ καὶ ἄνευ ψόφου τοιούτων ὀφθέντων νεφῶν χάλαζα γίγνεται πολλὴ καὶ τὸ μέγεθος ἄπιστος, καὶ τοῖς σχήμασιν οὐ στρογγύλη, διὰ τὸ μὴ πολὺν χρόνον γίγνεσθαι τὴν φορὰν αὐτῆς ὡς πλησίον τῆς πήξεως γενομένης τῆς γῆς, ἀλλ' οὐχ ὥσπερ ἐκεῖνοί φασιν.	113 Again clouds have often been observed moving with a great noise close to the earth, terrifying those who heard and saw them as portents of some catastrophe. Sometimes, too, when such clouds have been seen, without any noise, there follows a violent hailstorm, and the stones are of incredible size, and angular in shape. This shows that they have not been falling for long and that they were frozen near to the earth, and not as that theory would have it.
ἀλλὰ μὴν ἀναγκαῖον ὑπὸ τοῦ μάλιστ' αἰτίου τῆς πήξεως μεγάλας γίγνεσθαι χαλάζας κρύσταλλος γὰρ ἡ χάλαζα, καὶ τοῦτο παντὶ δῆλον. μεγάλαι δ' εἰσὶν αἱ τοῖς σχήμασιν μὴ στρογγύλαι. τοῦτο δ' ἐστὶ σημεῖον τοῦ παγῆναι πλησίον τῆς γῆς αἱ γὰρ φερόμεναι πόρρωθεν διὰ τὸ φέρεσθαι μακρὰν περιθραυόμεναι γίγνονται τό τε σχῆμα περιφερεῖς καὶ τὸ μέγεθος ἐλάττους. ὅτι μὲν (348b.) οὖν οὐ τῷ ἀπωθεῖσθαι εἰς τὸν ἄνω τόπον τὸν ψυχρὸν ἡ πῆξις συμβαίνει, δῆλον	114 Moreover, where the hailstones are large, the cause of their freezing must be present in the highest degree: for hail is ice as every one can see. Now those hailstones are large which are angular in shape. And this shows that they froze close to the earth, for those that fall far are worn away by the length of their fall and become round and smaller in size. It clearly follows that the congelation does not take place because the cloud is thrust up into the cold upper region.
ἀλλ' ἐπειδὴ ὁρῶμεν ὅτι γίγνεται ἀντιπερίστασις τῷ θερμῷ καὶ ψυχρῷ ἀλλήλοις (διὸ ἔν τε ταῖς ἀλέαις ψυχρὰ τὰ κάτω τῆς γῆς καὶ ἀλεεινὰ ἐν τοῖς πάγοις), τοῦτο δεῖ νομίζειν καὶ ἐν τῷ ἄνω γίγνεσθαι τόπῳ, ὥστ' ἐν ταῖς ἀλεεινοτέραις ὥραις ἀντιπεριιστάμενον εἴσω τὸ ψυχρὸν διὰ τὴν κύκλῳ θερμότητα ὁτὲ μὲν ταχὺ ὕδωρ ἐκ νέφους ποιεῖ διὸ καὶ αἱ ψακάδες πολὺ μείζους ἐν ταῖς ἀλεειναῖς γίγνονται ἡμέραις ἢ ἐν τῷ χειμῶνι, καὶ ὕδατα λαβρότερα λαβρότερα μὲν γὰρ λέγεται ὅταν ἀθροώτερα, ἀθροώτερα δὲ διὰ τὸ τάχος τῆς πυκνώσεως. (τοῦτο δὲ γίγνεται αὐτὸ τοὐναντίον ἢ ὡς Ἀναξαγόρας λέγει ὁ μὲν γὰρ ὅταν εἰς τὸν ψυχρὸν ἀέρα ἐπανέλθῃ φησὶ τοῦτο πάσχειν, ἡμεῖς δ' ὅταν εἰς τὸν θερμὸν κατέλθῃ, καὶ μάλιστα ὅταν μάλιστα.) ὅταν δ' ἔτι μᾶλλον ἀντιπεριστῇ ἐντὸς τὸ ψυχρὸν ὑπὸ τοῦ ἔξω θερμοῦ, ὕδωρ ποιῆσαν ἔπηξεν καὶ γίγνεται χάλαζα.	115 Now we see that warm and cold react upon one another by recoil. Hence in warm weather the lower parts of the earth are cold and in a frost they are warm. The same thing, we must suppose, happens in the air, so that in the warmer seasons the cold is concentrated by the surrounding heat and causes the cloud to go over into water suddenly. (For this reason rain-drops are much larger on warm days than in winter, and showers more violent. A shower is said to be more violent in proportion as the water comes down in a body, and this happens when the condensation takes place quickly,—though this is just the opposite of what Anaxagoras says. He says that this happens when the cloud has risen into the cold air; whereas we say that it happens when the cloud has descended into the warm air, and that the more the further the cloud has descended). But when the cold has been concentrated within still more by the outer heat, it freezes the water it has formed and there is hail.
συμβαίνει δὲ τοῦτο ὅταν θᾶττον ᾖ ἡ πῆξις ἢ ἡ τοῦ ὕδατος φορὰ ἡ κάτω εἰ γὰρ φέρεται μὲν ἐν τοσῷδε χρόνῳ, ἡ δὲ ψυχρότης σφοδρὰ οὖσα ἐν ἐλάττονι ἔπηξεν, οὐδὲν κωλύει μετέωρον παγῆναι, ἐὰν ἡ πῆξις ἐν ἐλάττονι γίγνηται χρόνῳ τῆς κάτω φορᾶς. καὶ ὅσῳ δ' ἂν ἐγγύτερον καὶ ἀθροωτέρα γένηται ἡ πῆξις, τά τε ὕδατα λαβρότερα γίγνεται καὶ αἱ ψακάδες καὶ αἱ χάλαζαι μείζους διὰ τὸ βραχὺν φέρεσθαι τόπον. καὶ οὐ πυκναὶ αἱ ψακάδες αἱ μεγάλαι πίπτουσιν διὰ τὴν αὐτὴν αἰτίαν.	116 We get hail when the process of freezing is quicker than the descent of the water. For if the water falls in a certain time and the cold is sufficient to freeze it in less, there is no difficulty about its having frozen in the air, provided that the freezing takes place in a shorter time than its fall. The nearer to the earth, and the more suddenly, this process takes place, the more violent is the rain that results and the larger the raindrops and the hailstones because of the shortness of their fall. For the same reason large raindrops do not fall thickly.
ἧττον δὲ τοῦ θέρους γίγνεται ἢ ἔαρος καὶ μετοπώρου, μᾶλλον μέντοι ἢ χειμῶνος, ὅτι ξηρότερος ὁ ἀὴρ τοῦ θέρους ἐν δὲ τῷ ἔαρι ἔτι ὑγρός, ἐν δὲ τῷ μετοπώρῳ ἤδη ὑγραίνεται. γίγνονται δέ ποτε, καθάπερ εἴρηται, καὶ τῆς ὀπώρας χάλαζαι διὰ τὴν αὐτὴν αἰτίαν.	117 Hail is rarer in summer than in spring and autumn, though commoner than in winter, because the air is drier in summer, whereas in spring it is still moist, and in autumn it is beginning to grow moist. It is for the same reason that hailstorms sometimes occur in the late summer as we have said.
συμβάλλεται δ' ἔτι πρὸς τὴν ταχυτῆτα τῆς πήξεως καὶ τὸ προτεθερμάνθαι τὸ ὕδωρ θᾶττον γὰρ ψύχεται. διὸ πολλοὶ ὅταν τὸ ὕδωρ ψῦξαι ταχὺ βουληθῶσιν, εἰς τὸν ἥλιον τιθέασι πρῶτον, καὶ οἱ περὶ τὸν Πόντον ὅταν ἐπὶ τοῦ κρυστάλλου σκηνοποιῶνται πρὸς τὰς τῶν ἰχθύων θήρας (θηρεύουσι γὰρ διακόπτοντες τὸν κρύσταλλον), ὕδωρ θερμὸν (349a.) περιχέουσι τοῖς καλάμοις διὰ τὸ θᾶττον πήγνυσθαι χρῶνται γὰρ τῷ κρυστάλλῳ ὥσπερ τῷ μολύβδῳ, ἵν' ἠρεμῶσιν οἱ κάλαμοι. θερμὸν δὲ γίγνεται ταχὺ τὸ συνιστάμενον ὕδωρ ἔν τε ταῖς χώραις καὶ ταῖς ὥραις ταῖς ἀλεειναῖς. γίγνεται δὲ καὶ περὶ τὴν Ἀραβίαν καὶ τὴν Αἰθιοπίαν τοῦ θέρους τὰ ὕδατα καὶ οὐ τοῦ χειμῶνος, καὶ ταῦτα ῥαγδαῖα, καὶ τῆς αὐτῆς ἡμέρας πολλάκις, διὰ τὴν αὐτὴν αἰτίαν ταχὺ γὰρ ψύχεται τῇ ἀντιπεριστάσει, ἣ γίγνεται διὰ τὸ ἀλεεινὴν εἶναι τὴν χώραν ἰσχυρῶς.	118 The fact that the water has previously been warmed contributes to its freezing quickly: for so it cools sooner. Hence many people, when they want to cool hot water quickly, begin by putting it in the sun. So the inhabitants of Pontus when they encamp on the ice to fish (they cut a hole in the ice and then fish) pour warm water round their reeds that it may freeze the quicker, for they use the ice like lead to fix the reeds. Now it is in hot countries and seasons that the water which forms soon grows warm. It is for the same reason that rain falls in summer and not in winter in Arabia and Ethiopia too, and that in torrents and repeatedly on the same day. For the concentration or recoil due to the extreme heat of the country cools the clouds quickly.
περὶ μὲν οὖν ὑετοῦ καὶ δρόσου καὶ νιφετοῦ καὶ πάχνης καὶ χαλάζης, διὰ τίν' αἰτίαν γίγνεται καὶ τίς ἡ φύσις αὐτῶν ἐστιν, εἰρήσθω τοσαῦτα.	119 So much for an account of the nature and causes of rain, dew, snow, hoar-frost, and hail.

Postquam philosophus determinavit de generatione pluviae, roris et pruinae, hic incipit determinare de generatione grandinis. Et circa hoc tria facit:	110. After determining about the generation of rain, dew and frost, the Philosopher here begins to determine about the formation of hail. About this he does three things:
primo ostendit locum generationis grandinis; secundo enumerat quaedam accidentia circa grandinem, quae faciunt difficultatem circa generationem ipsius, ibi: oportet autem accipere etc.; tertio assignat causam generationis eius, ibi: his quidem igitur et cetera.	First, he shows where hail is generated; Secondly, he enumerates certain phenomena accompanying hail that raise a difficulty about its formation, at 111; Thirdly, he assigns the cause of its generation, at 115.
Dicit ergo primo quod, licet vapor congeletur in hoc inferiori aere vicino terrae, tamen aqua non coagulatur hic ad generationem grandinis, sicut coagulatur in loco nubium. Ex illo enim loco veniunt tria corpora inspissata propter infrigidationem, scilicet aqua pluviae et nix et grando. Sed duobus horum corporum quaedam proportionalia fiunt in loco inferiori vicino terrae, quae ex eisdem causis generantur, sed differunt a pluvia et nive secundum magis et minus, prout scilicet citius vel tardius fit generatio, et secundum multitudinem et paucitatem.	He says therefore first [106], that although vapor freezes in this lower air near the earth, yet water does not coagulate here to form hail as it coagulates in the region of the clouds. For three bodies condensed by cold come from that region: namely, rain water, snow and hail. But in the case of two of these bodies, certain proportionate things take place in the lower region near the earth, and which are generated from the same causes, but differ from rain and snow according to more and less, depending, namely, on whether they are produced more quickly or more slowly, and on largeness and smallness [of amount].
Nix enim et pruina proportionaliter sunt idem, et similiter pluvia et ros: sed differunt secundum multum et paucum. Quia pluvia fit ex multo vapore infrigidato: huius autem multitudinis causa est et locus magnus et spatiosus, et multum tempus in quo vapor adunatur et colligitur, et multus etiam locus ex quo colligitur; quia enim in alto generantur pluviae, ex multis partibus illuc concurrunt vapores. Ros autem habet paucum de vapore, quia tempus in quo colligitur est paucum (consistentia enim illius vaporis est ephemeros, idest unius diei), et locus in quo congregatur parvus est, quia congregatur in propinquo terrae: et hoc manifestum fit per hoc quod generatio roris est velox, et multitudo eius est parva. Et sicut se habet de rore et pluvia, ita se habet de nive et pruina: quando enim tota nubes congelatur, fit nix; quando vero aliquis parvus vapor circa terram congelatur, tunc fit pruina. Et ideo utrumque eorum est signum temporis aut regionis frigidae: quia cum in vapore et nube adhuc sit aliquid de caliditate, non congelaretur nisi esset magnum frigus supervincens caliditatem ipsam; quia in nube adhuc multum residuum est de calore qui fecit evaporare humidum aqueum a terra, in vapore autem adhuc magis. Sic ergo, sicut pluvia et nix fiunt superius, ita ros et pruina inferius. Sed tamen, licet grando fiat superius, non convenit ei proportionale inferius: et huius causa erit manifesta, cum exposita fuerit causa generationis grandinis.	For snow and frost are proportionately the same, and likewise rain and dew: they differ according to abundance and scarcity. For rain comes to be from the cooling of an abundance of vapor — the cause of this abundance being a large and spacious region and a long time in which the vapor is being united and collected, and also a large place from which it is collected. For, since rains are generated on high, vapors collect there from many regions. Dew, on the other hand, has little vapor, because the time is short during which it is collected (for the consistency of that vapor is "ephemeral," i.e., of a single day), and the region is small in which it is collected, for it is collected close to the earth — and this becomes plain fog from the fact that the generating of dew is swift and its amount is small. And as it is with dew and rain, so with snow and frost: for when an entire cloud is frozen, snow comes to be; but when some small vapor near the earth freezes, frost comes to be. Therefore, both of them are a sign of cold weather or of a cold region — for, since some heat still abides in both the vapor and the cloud, they would not freeze, unless there were present a vast coldness overwhelming that heat: there being in the cloud still a large residue of the heat which made the watery moisture evaporate from the earth, and in the vapor still more. Thus, as rain and snow come to be in the upper region, so dew and frost in the lower. But although hail comes to be in the upper region, nothing below corresponds to it: the reason for this will be plain, when the cause of the generation of hail is explained.
Deinde cum dicit: oportet autem accipere etc., proponit quaedam accidentia quae accidunt circa grandinem, et faciunt difficultatem circa generationem ipsius.	111. Then [107] he proposes certain phenomena that occur with respect to hail and create a difficulty as to its generation;
Et proponit duas difficultates circa generationem grandinis: secundam ponit ibi: inconveniens autem et cetera.	And he proposes two difficulties with respect to generation of hail; The second one is mentioned at 112.
Dicit ergo primo quod oportet accipere ea quae accidunt circa generationem grandinis, quae putantur esse rationabilia, et non sunt falsa. Et primo proponit quod grando est sicut crystallus quidam, idest aqua vehementer congelata: et proponit iterum quod aqua maxime congelatur in hieme: ex quibus videtur sequi quod grando maxime fiat in hieme. Sed contrarium videtur accidere: quia grandines maxime fiunt in vere et in autumno; et post hoc, tempore fructuum, idest in aestate et circa principium autumni; minus autem in hieme, et tunc quando fuerit minus frigus hiemis. Et universaliter grandines fiunt in locis magis temperatis: nives autem in frigidioribus locis et temporibus. Unde et grandines, in quibus apparet maior congelatio, magis deberent fieri locis et temporibus frigidis.	He says therefore first [107], that with respect to the generation of hail we must consider the facts which are thought to be reasonable, and not false. And first he proposes that hail is, as it were, "crystal," i.e., water solidly frozen; he further proposes that water freezes especially in winter. But the contrary is seen to happen: for hailstorms occur mainly in spring and autumn; and after this, during the time of fruit, i.e., in summer and around the onset of autumn; but less often in winter, and, in that case, when the cold of winter has been less. Generally speaking, hail occurs in more temperate places; snow in colder places and times. From all this it would seem that hail, in which a larger amount of freezing is involved, ought rather to occur in places and times that are cold.
Deinde cum dicit: inconveniens autem etc., ponit secundam difficultatem. Et circa hoc tria facit. Primo ponit difficultatem. Et dicit quod inconveniens videtur quod aqua congeletur superius: quia non potest congelari antequam sit facta; neque postquam est facta, remanere elevata, quoniam statim cadit. Unde non videtur quod possit dari tempus in quo congeletur ad generationem grandinis.	112. Then at [108] he presents a second difficulty, about which he does three things. First, he presents the difficulty and says that it appears inconsistent that water should freeze on high — for it cannot freeze before it is formed, nor after it is formed, can it remain aloft, since it falls immediately. Hence it does not appear that there can be time for it to freeze and generate hail.
Secundo ibi: at vero neque quemadmodum etc., ponit quandam apparentem solutionem huius difficultatis. Posset enim aliquis dicere quod aqua, divisa in partes minimas, remanet in aere quasi ei commixta; et non cadit statim, sed immoratur in aere. Et per hunc modum accidit quando cadunt psecades, de quibus supra dictum est. Et simile est etiam de terra respectu aquae, quae ita se habet ad terram sicut aer ad aquam: frequenter enim aurum vel terra supernatat aquae propter parvitatem partium; sed si congregarentur illae partes terrae vel auri, caderent sub aqua. Unde, congregatis parvis partibus aquae quae resident in aere, fiunt magnae guttae, et sic deorsum feruntur psecades. Et ita posset aliquis dicere non esse inconveniens quod aqua insidens aeri congelaretur ad generationem grandinis.	113. Secondly, he gives an apparent solution of this difficulty [109]. For one could say that the water, separated into minimal parts, remains in the air as though mingled with it, and does not fall at once, but abides in the air. This is what happens when "psecades" [droplets] fall, about which we spoke earlier. And a like thing is true of earth in respect to water, which is to earth, as air is to water: for often gold or earth float on water because of the minuteness of their particles; but if those particles of earth or gold coalesced, they would fall to the bottom of the water. Hence as a result of the small particles that abide in the air congregating, large drops are formed and, in this way, the drops are brought down. In like manner, one could say that it is not impossible for water permeating the air to freeze and form hail.
Tertio ibi: hoc enim non contingit etc., excludit dictam solutionem: dicens quod non contingit fieri in grandine, sicut contingit in psecadibus. Quia partes aquae congelatae, si essent parvae, non possent uniri ut facerent aliquod magnum, sicut est grando, sicut continuantur partes aquae humidae existentis: quia duriora, ut sunt congelata, non ita adunantur sicut humidiora. Unde oporteret quod tanta aqua quanta est magnitudo grandinis, sursum maneret in aere non cadens: quod patet, quia non esset tanta post congelationem, si non fuisset tanta ante congelationem; ex multis enim parvis non possunt fieri multa magna continua. Sed quod tanta aqua sursum maneat non cadens, videtur impossibile.	114. Thirdly [110], he rejects this solution and says that what happens to occur in droplets does not occur in the case of hail. For bits of frozen water, if small, could not consolidate to form something large like hailstones in the way that the parts of water, as moist, coalesce: for hard objects, such as ice, do not unite the way more moist things do. Hence a quantity of water equal to the size of the hailstone would have had to be hanging above in the air without falling: this is evident, for it could not be the size it is after freezing, if it had not been that size before freezing — since from many small things cannot be formed many large continua. But that such an amount of water should remain above without falling seems impossible.
Deinde cum dicit: his quidem igitur etc., assignat causam generationis grandinis.	115. Then [111] he assigns the cause of the generation of hail.
Et primo ponit opinionem aliorum; secundo opinionem propriam, ibi: sed quoniam videmus et cetera.	First, he presents the opinions of others, at 115; Secondly, his own opinion, at 119.
Circa primum duo facit. Primo proponit opinionem aliorum. Et dicit quod quibusdam videtur quod, cum nubes ex magno calore fuerit impulsa in locum superiorem, qui est valde frigidus ex eo quod ibi desinunt radii refracti a terra, aqua veniens ibi coagulatur, propter frigiditatem loci. Et ideo in aestate et in regionibus calidis fiunt grandines, quia magnus calor multum impellit nubes in superiorem locum sursum longe a terra.	About the first he does two things: first, he presents the opinions of others [111] and says that it seems to some that when a large quantity of heat pushed a cloud into the upper region, which is very cold because the rays reflected from the earth do not reach there, the water arriving there is frozen on account of the region's being cold. And therefore the reason why hail occurs during the summer and in warm regions is that vast heat greatly pushes clouds into the upper region far from earth.
Secundo ibi: accidit autem etc., impugnat praedictam positionem tribus rationibus. Quarum prima est, quod videmus in altis montibus non fieri grandines: quod tamen oportebat, si per elevationem vaporis in locum multum altum generarentur grandines; sicut etiam videmus in montibus altis fieri nives, quae generantur in alto.	116. Secondly [112] he attacks this position on three scores. First, we see that hail does not occur on lofty mountains — but it should, if hail is formed by vapor lifted into very high places, just as we see snow, which is generated on high, on lofty mountains.
Secundam rationem ponit ibi: adhuc autem saepe et cetera. Et dicit quod saepe visae sunt nubes quae feruntur prope terram cum multo sono, ita ut quidam audientes cadentes terreantur, ac si aliquod maius futurum portendatur. Aliquando etiam, talibus nubibus visis prope terram sine sono, fit multa grando, incredibilis magnitudinis et figurae non rotundae. Hoc autem, scilicet quod grando non sit figurae rotundae et quod sit magnae quantitatis, accidit ex hoc quod congelatio grandinis est facta prope terram, et ideo parvo tempore fit motus ipsius: quia si multo tempore fieret, deminuta fuisset quantitas grandinis, et figura fuisset facta rotunda, motu dissolvente praecipue partes angulares, fortius dividentes aerem et magis ei resistentes. Non ergo verum est quod generatio grandinis fit multum longe a terra.	117. He gives the second argument [113] and says that clouds are often seen moving with a great noise close to the earth so that some people hearing it fall down in terror, as though it augured a great prodigy. At other times, when such clouds are seen near the earth without any noise, a great hailstorm occurs, with hailstones of incredible size and non-round shape. Now, these phenomena, namely, that the hail is not round in shape and that the stones are large, are due to the fact that the freezing of the hail took place near the earth; consequently its fall is of short duration — for if it had fallen a long time, the size of the hail would have been reduced and the shape rounded, because the descending motion would especially have dissolved the angled edges cleaving the air very strongly and offering it greater resistance. Therefore, it is not true that hail is generated very far from the earth.
Tertiam rationem ponit ibi: at vero necessarium et cetera. Et dicit quod necesse est quod magnitudo grandinis contingat ex fortitudine causae coagulationis grandinis: quia grando est quoddam congelatum sicut crystallus, ut est cuilibet manifestum. Sed magnitudo grandinis maior est in grandinibus quae non sunt rotundae: ex quo potest concludi quod grandines quae non sunt figurae rotundae, habeant fortem causam congelationis. Sed hoc quod grando non sit figurae rotundae, est signum quod sit congelata prope terram: quia si venirent de longe, circumquaque essent attritae, propter motum a longinquo, et sic essent figurae rotundae et magnitudine minores. Unde concludit quod coagulatio grandinis non accidit propter hoc quod vapores propellantur in locum frigidum supremum, multum remotum a terra.	118. He gives the third argument [114] and says that it is necessary that the size of the hail be due to the vigor of the cause freezing it: because hail is something congealed after the manner of crystal, as everyone can see. But the size of hail is greater when the stones are not round; from which it can be concluded that hailstones which are not round have vigorous cause of their freezing. But the very fact that the stone is not round is a sign that it froze close to the earth; because if the stones came from a great distance, their surface would have been worn down all over because of motion from a distance, and thus they would be round in shape and smaller in size. Hence he concludes that the freezing of hail is not due to vapors being pushed up into a highest cold region far from the earth.
Deinde cum dicit: sed quoniam videmus etc., assignat causam generationis grandinis.	119. Then [115] he assigns the cause of the generation of hail.
In quo primo excludit unam difficultatem superius motam; secundo excludit aliam, ibi: accidit autem hoc et cetera.	First, he excludes one difficulty raised earlier; Secondly, he excludes another one, at 120.
Dicit ergo primo quod per experimentum videmus quod calidum et frigidum sua contrarietate circumstant se invicem et aggregant. Et hoc manifestum est in terra. Nam in aestu interiora terrae sunt frigida, propter hoc quod caliditas aeris frigiditatem terrae circumstat; unde congregatur interius. E converso autem tempore frigoris interiora terrae sunt calida, propter hoc quod frigus concludit interius calorem qui erat in terra. Et inde est quod aqua fontium in aestate est frigida, et in hieme calida. Et hoc oportet putare fieri etiam in superiori loco. Unde in tempore calido frigidum, contrarietate calidi circumstantis inclusum, vehementius operatur: unde aliquando valde cito ex nube facit aquam. Et propter hoc multo maiores guttae fiunt in calidis diebus quam in hieme, et aquae pluviae fiunt labroterae, idest violentiores: quae quidem magnitudo et violentia accidunt ex eo quod quasi subito simul tota descendit pluvia, quod accidit propter celeritatem congelationis.	He says therefore first [115] that from frequent experience we observe that the hot and the cold being contrary surround each other and cause gathering. And this is evident in the case of the earth. For in the hot weather the interior of the earth is cold, due to the fact that the heat of the air surrounds earth's coldness; hence it congregates together within. On the other hand, when it is cold, the interior of the earth is warm, because the cold encloses inside the warmth which was in the earth. That is why in summer the water from fountains is cool but warm in winter. The same thing must be supposed to take place in the upper region also. Therefore, when the weather is warm, the cold, shut in by the contrariety of the warmth surrounding, acts with greater force — as a result, the coldness sometimes can form water very quickly from a cloud. And, for this reason, much larger drops are formed on hot days than in winter, and the rains are '"labroterae," i.e., more violent. The size and violence are due to the fact that a whole sheet of rain descends very suddenly, which is due to the rapidity of condensation.
Et sic contrarium accidit ei quod dixit Anaxagoras. Dicebat enim hoc accidere, quando vapor ex quo generatur pluvia, ascendit in aerem valde frigidum: sed nos e converso dicimus quod hoc accidit, cum vapor descendit in aerem calidum; et tanto magis, quanto in magis calidum. Sic igitur ex calido circumstante frigidum et congregante ipsum, fiunt magnae guttae pluviarum et violentae. Sed cum frigidum magis congregatur conclusum ab exteriori calido, non solum subito condensantur nubes in aquam, sed ulterius aqua congelatur ex vehementi virtute frigidi inclusi, et sic fit grando. Unde patet solutio primae difficultatis: quare scilicet aqua congelatur in grandinem magis tempore aestatis quam hiemis.	Therefore, what happens is the very contrary of Anaxagoras' theory, which held that this happens when the vapor, from which rain forms, rises into air which is very cold; but we, on the contrary, maintain that this happens when the vapor descends into warm air — and so much the more so according as the warmth is greater. Therefore, from the hot which surrounds and gathers together the cold, are due the large drops and the violence of the rain. But when the cold is still more gathered together as a result of being surrounded by an external warmth, not only are the clouds condensed into water suddenly but what is more, the water is frozen by the vehement power of the trapped coldness: then hail is formed. From this is plain the solution to the first difficulty: namely, why is water congealed into hail in warm weather more than in winter?
Deinde cum dicit: accidit autem hoc etc., solvit secundam difficultatem. Et circa hoc tria facit:	120. Then [1163 he solves the second difficulty. About this he does three things:
primo solvit difficultatem; secundo assignat rationem de tempore generationis grandinis, ibi: minus autem aestate etc.; tertio ponit quoddam conferens ad celeritatem generationis grandinis, ibi: confert autem et cetera.	First, he solves the difficulty; Secondly, he gives an explanation for the season in which hail is formed, 121. Thirdly, he lays down something that contributes to the speed with which hail is formed, at 122.
Fuit autem secunda difficultas ex hoc quod non videbatur posse dari tempus in quo superius aqua congelaretur in grandinem; quia statim dum aqua generatur, cadit; et antequam generetur, congelari non potest. Ad solvendam igitur hanc difficultatem, dicit quod generatio grandinis accidit, quando est velocior aquae congelatio, propter virtutem frigoris congregati, quam motus aquae pluviae deorsum.	The second difficulty arose from the fact that there did not seem to be able to be any time for the water on high to freeze into hail — for as soon as water is formed, it falls, and it cannot freeze before it has formed. To solve this difficulty, therefore, he says [116] that the generation of hail occurs when the freezing of water is more rapid (on account of the vigor of the cold gathered together) than the downward motion of the water.
Et quod hoc sit possibile, ostendit. Cum enim omnis motus localis sit in tempore, manifestum est quod in aliquo determinato tempore aqua pluviae fertur deorsum; contingit autem quod in minori tempore frigiditas, propter suam vehementiam, congelat aquam, quam sit tempus descensus eius; unde nihil prohibet si congelatio fiat in minori tempore quam motus deorsum aquae, si frigidum existat fortius et vehemens. Et hinc est quod quanto propinquius nobis fit generatio aquae vel grandinis, tanto magis subito congeletur, calido existente fortiori prope terram, et vehementius expellente et concludente frigidum. Et ideo oportet quod et aquae pluviae fiant violentiores, et tam guttae pluviarum quam grandinum sint maiores, propter hoc quod per minus spatium feruntur, et minus ex eis dissolvitur. Illae autem guttae quae cadunt magnae, non sunt crebrae, propter eandem causam: quia enim subito et simul congelantur in magnas, non in multas partes dividuntur, et subito etiam cadunt; sicque materia pluviae et grandinis non tam spissim cadit.	That this is possible he now shows. For since every instance of local motion is in time, it is plain that the rain water is traveling downward for some definite period of time; but it happens that the coldness, because of its vigor, freezes the water in less time than the time of descent. Hence there is nothing to prevent the freezing from occurring in less time than it takes the water to descend, if the cold is very vigorous and intense. This is why, the nearer to us the generation of water or hail takes place, the faster it freezes, since the heat is stronger near the earth and more vigorously expels and encloses the cold. In these circumstances the water of the rain must become more violent, and both the drops of rain and the hailstones larger, because they travel a shorter distance and less is dissolved away. For the same reason the raindrops do not fall thickly, for, since they suddenly condense into large drops at one time, they are not divided into many parts, and also fall very quickly — and that is why the stuff of rain and hail does not fall so thickly.
Deinde cum dicit: minus autem aestate etc., assignat rationem de tempore generationis grandinis. Et dicit quod minus cadunt grandines in aestate quam in vere et in autumno, sed magis quam in hieme. Ideo autem minus in aestate quam in vere et autumno, quia in aestate est siccior aer; in vere autem est adhuc humidus, propter hiemem praecedentem, et in autumno iam incipit humectari. Et sic in aestate non est tanta materia vaporum humidorum ad generationem grandinis, sicut in vere et in autumno, licet sit maior calor. In hieme autem, licet abundet materia, deficit tamen calor qui sit potens concludere frigidum ad generationem grandinis. Fiunt etiam grandines tempore maturationis fructuum, idest in fine aestatis, propter eandem causam: quia tunc calor adhuc viget, et etiam aer iam incipit humectari.	121. Then [117] he assigns a reason for the time when hail is generated, and says that hail falls less in summer than in spring and autumn, but more than in winter: less in summer than in spring and autumn, because in summer the air is drier; but in spring the air is still moist on account of the preceding winter, while in autumn, it is already beginning to grow moist. Hence in summer there is not as much moist vapor for generation of hail as in spring and autumn, although there is more heat. But in winter, although there is an abundance of material, there is lack of heat to concentrate the cold that generates hail. Also hail occurs at harvest time, i.e., in late summer, for the same reason: because the heat is then still potent and the air is beginning to get moist.
Deinde cum dicit: confert autem etc., quia difficultatem superius motam solverat propter velocitatem generationis grandinis, contingentem ex vehementia frigoris, ponit hic quoddam aliud conferens ad celeritatem eandem. Et dicit quod confert ad celeritatem coagulationis, quod aqua fuit praecalefacta, adiuvante materia vaporosa caliditatem temporis: et ideo citius infrigidatur, quia frigus vehementius agit in ipsam, et potest intrinsecus penetrare aquam rarefactam per calorem. Et ideo multi, cum volunt infrigidare calidam aquam, ponunt eam ad solem primo. Et illi etiam qui piscantur in regione Ponti, cum fecerint habitacula tempore glaciei ad venandum pisces, quos venantur scindentes glaciem fluviorum vel maris, circumfundunt aquam calidam calamis quibus venantur, ut citius coaguletur; et sic utuntur glacie quasi plumbo, ut calami firmiter quiescant. Sed et in regionibus et in temporibus calidis aqua calida fit cito frigida, eo quod cito inspissatur, propter praedictam causam. Et ideo in Arabia et Aethiopia fiunt pluviae aestate et non hieme: quia scilicet vapores cito infrigidantur ex contrarietate calidi circumstantis, cum regio illa sit valde calida.	122. Then [118], because he had solved the difficulty raised above by citing the speed with which hail is generated on account of the vigorous cold, he now posits something else that contributes to this same speed. And he says that a contribution to the speed of the coagulating process is the fact that the water is pre-heated (the vaporous stuff aiding the season's heat) and therefore freezes more quickly, because the cold acts upon it more vigorously and can penetrate farther into water that has been rarified by the heat. This is the reason why many people; when they want to cool warm water, first place it in the sun. And fishermen in the region of Pontus, when they make huts during the ice season to fish (they catch the fish through holes cut in the ice of the sea or river), pour hot water around the poles they use for fishing, so that it will freeze faster; in this way they use the frozen water, as though it were lead, to keep the poles firmly fixed. But in warm regions and in warm seasons, hot water cools quickly, because it gets dense quickly, for the reason given. Hence,-in Arabia and Ethiopia, rains occur in summer and not in winter, because the vapors are quickly cooled by reason of the contrariety of the heat surrounding them, since this region is very hot.
Ultimo autem epilogat quae dicta sunt: et est planum in littera.	Finally [119] he summarizes what has been said — and this is plain in the text.

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Lecture 16 The cause of the generation of rivers
Chapter 13
περὶ δὲ ἀνέμων καὶ πάντων πνευμάτων, ἔτι δὲ ποταμῶν καὶ θαλάττης λέγωμεν, πρῶτον καὶ περὶ ούτων διαπορήσαντες πρὸς ἡμᾶς αὐτούς ὥσπερ γὰρ καὶ περὶ ἄλλων, οὕτως καὶ περὶ τούτων οὐδὲν παρειλήφαμεν λεγόμενον τοιοῦτον ὃ μὴ κἂν ὁ τυχὼν εἴπειεν.	120 Let us explain the nature of winds, and all windy vapours, also of rivers and of the sea. But here, too, we must first discuss the difficulties involved: for, as in other matters, so in this no theory has been handed down to us that the most ordinary man could not have thought of.
εἰσὶ δέ τινες οἵ φασι τὸν καλούμενον ἀέρα κινούμενον μὲν καὶ ῥέοντα ἄνεμον εἶναι, συνιστάμενον δὲ τὸν αὐτὸν τοῦτον πάλιν νέφος καὶ ὕδωρ, ὡς τῆς αὐτῆς φύσεως οὔσης ὕδατος καὶ πνεύματος, καὶ τὸν ἄνεμον εἶναι κίνησιν ἀέρος. διὸ καὶ τῶν σοφῶς βουλομένων λέγειν τινὲς ἕνα φασὶν ἄνεμον εἶναι πάντας τοὺς ἀνέμους, ὅτι συμπέπτωκε καὶ τὸν ἀέρα τὸν κινούμενον ἕνα καὶ τὸν αὐτὸν εἶναι πάντα, δοκεῖν δὲ διαφέρειν οὐδὲν διαφέροντα διὰ τοὺς τόπους ὅθεν ἂν τυγχάνῃ ῥέων ἑκάστοτε, παραπλησίως λέγοντες ὥσπερ ἂν εἴ τις οἴοιτο καὶ τοὺς ποταμοὺς πάντας ἕνα ποταμὸν εἶναι. διὸ βέλτιον οἱ πολλοὶ λέγουσιν ἄνευ ζητήσεως τῶν μετὰ ζητήσεως οὕτω λεγόντων εἰ μὲν γὰρ ἐκ μιᾶς ἀρχῆς ἅπαντες ῥέουσι, κἀκεῖ τὰ πνεύματα τὸν αὐτὸν τρόπον, τάχα λέγοιεν ἄν τι οἱ λέγοντες οὕτως εἰ δ' ὁμοίως ἐνταῦθα κἀκεῖ, δῆλον ὅτι τὸ κόμψευμα ἂν εἴη τοῦτο ψεῦδος, ἐπεὶ τοῦτό γε προσήκουσαν ἔχει σκέψιν, τί τ' ἐστὶν ὁ ἄνεμος, καὶ γίγνεται πῶς, καὶ τί τὸ κινοῦν, καὶ ἡ ἀρχὴ πόθεν αὐτῶν, καὶ πότερον ἄρ' ὥσπερ ἐξ ἀγγείου δεῖ λαβεῖν ῥέοντα τὸν ἄνεμον, καὶ μέχρι τούτου ῥεῖν ἕως ἂν κενωθῇ τὸ ἀγγεῖον, οἷον ἐξ ἀσκῶν ἀφιέμενον, (349b.) ἢ καθάπερ καὶ οἱ γραφεῖς γράφουσιν, ἐξ αὑτῶν τὴν ἀρχὴν ἀφιέντας.	121 Some say that what is called air, when it is in motion and flows, is wind, and that this same air when it condenses again becomes cloud and water, implying that the nature of wind and water is the same. So they define wind as a motion of the air. Hence some, wishing to say a clever thing, assert that all the winds are one wind, because the air that moves is in fact all of it one and the same; they maintain that the winds appear to differ owing to the region from which the air may happen to flow on each occasion, but really do not differ at all. This is just like thinking that all rivers are one and the same river, and the ordinary unscientific view is better than a scientific theory like this. If all rivers flow from one source, and the same is true in the case of the winds, there might be some truth in this theory; but if it is no more true in the one case than in the other, this ingenious idea is plainly false. What requires investigation is this: the nature of wind and how it originates, its efficient cause and whence they derive their source; whether one ought to think of the wind as issuing from a sort of vessel and flowing until the vessel is empty, as if let out of a wineskin, or, as painters represent the winds, as drawing their source from themselves.
ὁμοίως δὲ καὶ περὶ τῆς τῶν ποταμῶν γενέσεως δοκεῖ τισιν ἔχειν τὸ γὰρ ἀναχθὲν ὑπὸ τοῦ ἡλίου ὕδωρ πάλιν ὑόμενον ἀθροισθὲν ὑπὸ γῆν ῥεῖν ἐκ κοιλίας μεγάλης, ἢ πάντας μιᾶς ἢ ἄλλον ἄλλης καὶ οὐ γίγνεσθαι ὕδωρ οὐδέν, ἀλλὰ τὸ συλλεχθὲν ἐκ τοῦ χειμῶνος εἰς τὰς τοιαύτας ὑποδοχάς, τοῦτο γίγνεσθαι τὸ πλῆθος τὸ τῶν ποταμῶν. διὸ καὶ μείζους ἀεὶ τοῦ χειμῶνος ῥεῖν ἢ τοῦ θέρους, καὶ τοὺς μὲν ἀενάους εἶναι τοὺς δ' οὐκ ἀενάους ὅσων μὲν γὰρ διὰ τὸ μέγεθος τῆς κοιλίας πολὺ τὸ συλλεγόμενον ὕδωρ ἐστίν, ὥστε διαρκεῖν καὶ μὴ προαναλίσκεσθαι πρὶν ἐπελθεῖν τὸ ὄμβριον ἐν τῷ χειμῶνι πάλιν, τούτους μὲν ἀενάους εἶναι διὰ τέλους, ὅσοις δὲ ἐλάττους αἱ ὑποδοχαί, τούτους δὲ δι' ὀλιγότητα τοῦ ὕδατος φθάνειν ξηραινομένους πρὶν ἐπελθεῖν τὸ ἐκ τοῦ οὐρανοῦ, κενουμένου τοῦ ἀγγείου.	122 We find analogous views about the origin of rivers. It is thought that the water is raised by the sun and descends in rain and gathers below the earth and so flows from a great reservoir, all the rivers from one, or each from a different one. No water at all is generated, but the volume of the rivers consists of the water that is gathered into such reservoirs in winter. Hence rivers are always fuller in winter than in summer, and some are perennial, others not. Rivers are perennial where the reservoir is large and so enough water has collected in it to last out and not be used up before the winter rain returns. Where the reservoirs are smaller there is less water in the rivers, and they are dried up and their vessel empty before the fresh rain comes on.
καίτοι φανερόν, εἴ τις βούλεται ποιήσας οἷον ὑποδοχὴν πρὸ ὀμμάτων τῷ καθ' ἡμέραν ὕδατι ῥέοντι συνεχῶς νοῆσαι τὸ πλῆθος ὑπερβάλλοι γὰρ ἂν τῷ μεγέθει τὸν τῆς γῆς ὄγκον ἢ οὐ πολὺ ἂν ἐλλείποι τὸ δεχόμενον πᾶν τὸ ῥέον ὕδωρ εἰς τὸν ἐνιαυτόν. ἀλλὰ δῆλον ὅτι συμβαίνει μὲν καὶ πολλὰ τοιαῦτα πολλαχοῦ τῆς γῆς,	123 But if any one will picture to himself a reservoir adequate to the water that is continuously flowing day by day, and consider the amount of the water, it is obvious that a receptacle that is to contain all the water that flows in the year would be larger than the earth, or, at any rate, not much smaller. Though it is evident that many reservoirs of this kind do exist in many parts of the earth,
οὐ μὴν ἀλλ' ἄτοπον εἴ τις μὴ νομίζει διὰ τὴν αὐτὴν αἰτίαν ὕδωρ ἐξ ἀέρος γίγνεσθαι δι' ἥνπερ ὑπὲρ γῆς καὶ ἐν τῇ γῇ. ὥστ' εἴπερ κἀκεῖ διὰ ψυχρότητα συνίσταται ὁ ἀτμίζων ἀὴρ εἰς ὕδωρ, καὶ ὑπὸ τῆς ἐν τῇ γῇ ψυχρότητος τὸ αὐτὸ τοῦτο δεῖ νομίζειν συμβαίνειν, καὶ γίγνεσθαι μὴ μόνον τὸ ἀποκεκριμένον ὕδωρ ἐν αὐτῇ, καὶ τοῦτο ῥεῖν, ἀλλὰ καὶ γίγνεσθαι συνεχῶς.	123 yet it is unreasonable for any one to refuse to admit that air becomes water in the earth for the same reason as it does above it. If the cold causes the vaporous air to condense into water above the earth we must suppose the cold in the earth to produce this same effect, and recognize that there not only exists in it and flows out of it actually formed water, but that water is continually forming in it too.
ἔτι δὲ τοῦ μὴ γιγνομένου ἀλλ' ὑπάρχοντος ὕδατος καθ' ἡμέραν μὴ τοιαύτην εἶναι τὴν ἀρχὴν τῶν ποταμῶν, οἷον ὑπὸ γῆν λίμνας τινὰς ἀποκεκριμένας, καθάπερ ἔνιοι λέγουσιν, ἀλλ' ὁμοίως ὥσπερ καὶ ἐν τῷ ὑπὲρ γῆς τόπῳ μικραὶ συνιστάμεναι ῥανίδες, καὶ πάλιν αὗται ἑτέραις, τέλος μετὰ πλήθους καταβαίνει τὸ ὑόμενον ὕδωρ, οὕτω καὶ ἐν τῇ γῇ ἐκ μικρῶν συλλείβεσθαι τὸ πρῶτον καὶ εἶναι οἷον πιδώσης εἰς ἓν τῆς γῆς τὰς ἀρχὰς τῶν ποταμῶν. δηλοῖ δ' αὐτὸ τὸ ἔργον οἱ γὰρ τὰς ὑδραγωγίας (350a.) ποιοῦντες ὑπονόμοις καὶ διώρυξι συνάγουσιν, ὥσπερ ἂν ἰδιούσης τῆς γῆς ἀπὸ τῶν ὑψηλῶν.	125 Again, even in the case of the water that is not being formed from day to day but exists as such, we must not suppose as some do that rivers have their source in definite subterranean lakes. On the contrary, just as above the earth small drops form and these join others, till finally the water descends in a body as rain, so too we must suppose that in the earth the water at first trickles together little by little, and that the sources of the rivers drip, as it were, out of the earth and then unite. This is proved by facts. When men construct an aqueduct they collect the water in pipes and trenches, as if the earth in the higher ground were sweating the water out.
διὸ καὶ τὰ ῥεύματα τῶν ποταμῶν ἐκ τῶν ὀρῶν φαίνεται ῥέοντα, καὶ πλεῖστοι καὶ μέγιστοι ποταμοὶ ῥέουσιν ἐκ τῶν μεγίστων ὀρῶν. ὁμοίως δὲ καὶ αἱ κρῆναι αἱ πλεῖσται ὄρεσιν καὶ τόποις ὑψηλοῖς γειτνιῶσιν ἐν δὲ τοῖς πεδίοις ἄνευ ποταμῶν ὀλίγαι γίγνονται πάμπαν. οἱ γὰρ ὀρεινοὶ καὶ ὑψηλοὶ τόποι, οἷον σπόγγος πυκνὸς ἐπικρεμάμενοι, κατὰ μικρὰ μὲν πολλαχῇ δὲ διαπιδῶσι καὶ συλλείβουσι τὸ ὕδωρ δέχονταί τε γὰρ τοῦ κατιόντος ὕδατος πολὺ πλῆθος (τί γὰρ διαφέρει κοίλην καὶ ὑπτίαν ἢ πρηνῆ τὴν περιφέρειαν εἶναι καὶ κυρτήν; ἀμφοτέρως γὰρ τὸν ἴσον ὄγκον περιλήψεται σώματος) καὶ τὴν ἀνιοῦσαν ἀτμίδα ψύχουσι καὶ συγκρίνουσι πάλιν εἰς ὕδωρ διό, καθάπερ εἴπομεν, οἱ μέγιστοι τῶν ποταμῶν ἐκ τῶν μεγίστων φαίνονται ῥέοντες ὀρῶν. δῆλον δ' ἐστὶ τοῦτο θεωμένοις τὰς τῆς γῆς περιόδους ταύτας γὰρ ἐκ τοῦ πυνθάνεσθαι παρ' ἑκάστων οὕτως ἀνέγραψαν, ὅσων μὴ συμβέβηκεν αὐτόπτας γενέσθαι τοὺς λέγοντας. ἐν μὲν οὖν τῇ Ἀσίᾳ πλεῖστοι μὲν ἐκ τοῦ Παρνασσοῦ καλουμένου φαίνονται ῥέοντες ὄρους καὶ μέγιστοι ποταμοί, τοῦτο δ' ὁμολογεῖται πάντων εἶναι μέγιστον τὸ ὄρος τῶν πρὸς τὴν ἕω τὴν χειμερινήν ὑπερβάντι γὰρ ἤδη τοῦτο φαίνεται ἡ ἔξω θάλαττα, ἧς τὸ πέρας οὐ δῆλον τοῖς ἐντεῦθεν. ἐκ μὲν οὖν τούτου ῥέουσιν ἄλλοι τε ποταμοὶ καὶ ὁ Βάκτρος καὶ ὁ Χοάσπης καὶ ὁ Ἀράξης τούτου δ' ὁ Τάναϊς ἀποσχίζεται μέρος ὢν εἰς τὴν Μαιῶτιν λίμνην. ῥεῖ δὲ καὶ ὁ Ἰνδὸς ἐξ αὐτοῦ, πάντων τῶν ποταμῶν ῥεῦμα πλεῖστον. ἐκ δὲ τοῦ Καυκάσου ἄλλοι τε ῥέουσι πολλοὶ καὶ κατὰ πλῆθος καὶ κατὰ μέγεθος ὑπερβάλλοντες, καὶ ὁ Φᾶσις ὁ δὲ Καύκασος μέγιστον ὄρος τῶν πρὸς τὴν ἕω τὴν θερινήν ἐστιν καὶ πλήθει καὶ ὕψει. σημεῖα δὲ τοῦ μὲν ὕψους ὅτι ὁρᾶται καὶ ἀπὸ τῶν καλουμένων βαθέων καὶ εἰς τὴν λίμνην εἰσπλεόντων, ἔτι δ' ἡλιοῦται τῆς νυκτὸς αὐτοῦ τὰ ἄκρα μέχρι τοῦ τρίτου μέρους ἀπό τε τῆς ἕω καὶ πάλιν ἀπὸ τῆς ἑσπέρας τοῦ δὲ πλήθους ὅτι πολλὰς ἔχον ἕδρας, ἐν αἷς ἔθνη τε κατοικεῖ πολλὰ καὶ λίμνας εἶναί φασι μεγάλας, ἀλλ' ὅμως πάσας τὰς ἕδρας εἶναί φασι φανερὰς μέχρι τῆς ἐσχάτης κορυφῆς. ἐκ δὲ (350b.) τῆς Πυρήνης (τοῦτο δ' ἐστὶν ὄρος πρὸς δυσμὴν ἰσημερινὴν ἐν τῇ Κελτικῇ) ῥέουσιν ὅ τε Ἴστρος καὶ ὁ Ταρτησσός. οὗτος μὲν οὖν ἔξω στηλῶν, ὁ δ' Ἴστρος δι' ὅλης τῆς Εὐρώπης εἰς τὸν Εὔξεινον πόντον. τῶν δ' ἄλλων ποταμῶν οἱ πλεῖστοι πρὸς ἄρκτον ἐκ τῶν ὀρῶν τῶν Ἀρκυνίων ταῦτα δὲ καὶ ὕψει καὶ πλήθει μέγιστα περὶ τὸν τόπον τοῦτόν ἐστιν. ὑπ' αὐτὴν δὲ τὴν ἄρκτον ὑπὲρ τῆς ἐσχάτης Σκυθίας αἱ καλούμεναι Ῥῖπαι, περὶ ὧν τοῦ μεγέθους λίαν εἰσὶν οἱ λεγόμενοι λόγοι μυθώδεις ῥέουσι δ' οὖν οἱ πλεῖστοι καὶ μέγιστοι μετὰ τὸν Ἴστρον τῶν ἄλλων ποταμῶν ἐντεῦθεν, ὥς φασιν. ὁμοίως δὲ καὶ περὶ τὴν Λιβύην οἱ μὲν ἐκ τῶν Αἰθιοπικῶν ὀρῶν, ὅ τε Αἰγὼν καὶ ὁ Νύσης, οἱ δὲ μέγιστοι τῶν διωνομασμένων, ὅ τε Χρεμέτης καλούμενος, ὃς εἰς τὴν ἔξω ῥεῖ θάλατταν, καὶ τοῦ Νείλου τὸ ῥεῦμα τὸ πρῶτον, ἐκ τοῦ Ἀργυροῦ καλουμένου ὄρους. τῶν δὲ περὶ τὸν Ἑλληνικὸν τόπον ὁ μὲν Ἀχελῷος ἐκ Πίνδου, καὶ ὁ Ἴναχος ἐντεῦθεν, ὁ δὲ Στρυμὼν καὶ Νέσσος καὶ ὁ Ἕβρος ἅπαντες τρεῖς ὄντες ἐκ τοῦ Σκόμβρου πολλὰ δὲ ῥεύματα καὶ ἐκ τῆς Ῥοδόπης ἐστίν. ὁμοίως δὲ καὶ τοὺς ἄλλους ποταμοὺς εὕροι τις ἂν ῥέοντας ἀλλὰ μαρτυρίου χάριν τούτους εἴπομεν ἐπεὶ καὶ ὅσοι αὐτῶν ῥέουσιν ἐξ ἑλῶν, τὰ ἕλη ὑπὸ ὄρη κεῖσθαι συμβαίνει πάντα σχεδὸν ἢ τόπους ὑψηλοὺς ἐκ προσαγωγῆς.	126 Hence, too, the head-waters of rivers are found to flow from mountains, and from the greatest mountains there flow the most numerous and greatest rivers. Again, most springs are in the neighbourhood of mountains and of high ground, whereas if we except rivers, water rarely appears in the plains. For mountains and high ground, suspended over the country like a saturated sponge, make the water ooze out and trickle together in minute quantities but in many places. They receive a great deal of water falling as rain (for it makes no difference whether a spongy receptacle is concave and turned up or convex and turned down: in either case it will contain the same volume of matter) and, they also cool the vapour that rises and condense it back into water. Hence, as we said, we find that the greatest rivers flow from the greatest mountains. This can be seen by looking at itineraries: what is recorded in them consists either of things which the writer has seen himself or of such as he has compiled after inquiry from those who have seen them. In Asia we find that the most numerous and greatest rivers flow from the mountain called Parnassus, admittedly the greatest of all mountains towards the south-east. When you have crossed it you see the outer ocean, the further limit of which is unknown to the dwellers in our world. Besides other rivers there flow from it the Bactrus, the Choaspes, the Araxes: from the last a branch separates off and flows into lake Maeotis as the Tanais. From it, too, flows the Indus, the volume of whose stream is greatest of all rivers. From the Caucasus flows the Phasis, and very many other great rivers besides. Now the Caucasus is the greatest of the mountains that lie to the northeast, both as regards its extent and its height. A proof of its height is the fact that it can be seen from the so-called 'deeps' and from the entrance to the lake. Again, the sun shines on its peaks for a third part of the night before sunrise and again after sunset. Its extent is proved by the fact that thought contains many inhabitable regions which are occupied by many nations and in which there are said to be great lakes, yet they say that all these regions are visible up to the last peak. From Pyrene (this is a mountain towards the west in Celtice) there flow the Istrus and the Tartessus. The latter flows outside the pillars, while the Istrus flows through all Europe into the Euxine. Most of the remaining rivers flow northwards from the Hercynian mountains, which are the greatest in height and extent about that region. In the extreme north, beyond furthest Scythia, are the mountains called Rhipae. The stories about their size are altogether too fabulous: however, they say that the most and (after the Istrus) the greatest rivers flow from them. So, too, in Libya there flow from the Aethiopian mountains the Aegon and the Nyses; and from the so-called Silver Mountain the two greatest of named rivers, the river called Chremetes that flows into the outer ocean, and the main source of the Nile. Of the rivers in the Greek world, the Achelous flows from Pindus, the Inachus from the same mountain; the Strymon, the Nestus, and the Hebrus all three from Scombrus; many rivers, too, flow from Rhodope. All other rivers would be found to flow in the same way, but we have mentioned these as examples. Even where rivers flow from marshes, the marshes in almost every case are found to lie below mountains or gradually rising ground.
ὅτι μὲν οὖν οὐ δεῖ νομίζειν οὕτω γίγνεσθαι τὰς ἀρχὰς τῶν ποταμῶν ὡς ἐξ ἀφωρισμένων κοιλιῶν, φανερόν οὔτε γὰρ ἂν ὁ τόπος ἱκανὸς ἦν ὁ τῆς γῆς ὡς εἰπεῖν, ὥσπερ οὐδ' ὁ τῶν νεφῶν, εἰ τὸ ὂν ἔδει ῥεῖν μόνον, ἀλλὰ μὴ τὸ μὲν ἀπῄει τὸ δ' ἐγίγνετο, ἀλλ' αἰεὶ ἀπὸ ὄντος ἐταμιεύετο τό τε ὑπὸ τοῖς ὄρεσιν ἔχειν τὰς πηγὰς μαρτυρεῖ διότι τῷ συρρεῖν εἰς ὀλίγον καὶ κατὰ μικρὸν ἐκ πολλῶν νοτίδων διαδίδωσιν ὁ τόπος καὶ γίγνονται οὕτως αἱ πηγαὶ τῶν ποταμῶν.	127 It is clear then that we must not suppose rivers to originate from definite reservoirs: for the whole earth, we might almost say, would not be sufficient (any more than the region of the clouds would be) if we were to suppose that they were fed by actually existing water only and it were not the case that as some water passed out of existence some more came into existence, but rivers always drew their stream from an existing store. Secondly, the fact that rivers rise at the foot of mountains proves that a place transmits the water it contains by gradual percolation of many drops, little by little, and that this is how the sources of rivers originate.
οὐ μὴν ἀλλὰ καὶ τοιούτους εἶναι τόπους ἔχοντας πλῆθος ὕδατος, οἷον λίμνας, οὐδὲν ἄτοπον, πλὴν οὔτι τηλικαύτας ὥστε τοῦτο συμβαίνειν, οὐδὲν μᾶλλον ἢ εἴ τις οἴοιτο τὰς φανερὰς εἶναι πηγὰς τῶν ποταμῶν σχεδὸν γὰρ ἐκ κρηνῶν οἱ πλεῖστοι ῥέουσιν. ὅμοιον οὖν τὸ ἐκείνας καὶ τὸ ταύτας νομίζειν εἶναι τὸ σῶμα τὸ τοῦ ὕδατος πᾶν. ὅτι δ' εἰσὶν τοιαῦται φάραγγες καὶ διαστάσεις τῆς γῆς, (351a.) δηλοῦσιν οἱ καταπινόμενοι τῶν ποταμῶν. συμβαίνει δὲ τοῦτο πολλαχοῦ τῆς γῆς, οἷον τῆς μὲν Πελοποννήσου πλεῖστα τοιαῦτα περὶ τὴν Ἀρκαδίαν ἐστίν. αἴτιον δὲ διὰ τὸ ὀρεινὴν οὖσαν μὴ ἔχειν ἐκροὰς ἐκ τῶν κοίλων εἰς θάλατταν πληρούμενοι γὰρ οἱ τόποι καὶ οὐκ ἔχοντες ἔκρυσιν αὑτοῖς εὑρίσκονται τὴν δίοδον εἰς βάθος, ἀποβιαζομένου τοῦ ἄνωθεν ἐπιόντος ὕδατος. περὶ μὲν οὖν τὴν Ἑλλάδα μικρὰ τοιαῦτα παντελῶς ἐστιν γιγνόμενα ἀλλ' ἥ γε ὑπὸ τὸν Καύκασον λίμνη, ἣν καλοῦσιν οἱ ἐκεῖ θάλατταν αὕτη γὰρ ποταμῶν πολλῶν καὶ μεγάλων εἰσβαλλόντων οὐκ ἔχουσα ἔκρουν φανερὸν ἐκδίδωσιν ὑπὸ γῆν κατὰ Κοραξούς, περὶ τὰ καλούμενα βαθέα τοῦ Πόντου ταῦτα δ' ἐστὶν ἄπειρόν τι τῆς θαλάττης βάθος οὐδεὶς γοῦν πώποτε καθεὶς ἐδυνήθη πέρας εὑρεῖν. ταύτῃ δὲ πόρρω τῆς γῆς σχεδὸν περὶ τριακόσια στάδια πότιμον ἀναδίδωσιν ὕδωρ ἐπὶ πολὺν τόπον, οὐ συνεχῆ δέ, ἀλλὰ τρισσαχῇ. καὶ περὶ τὴν Λιγυστικὴν οὐκ ἐλάττων τοῦ Ῥοδανοῦ καταπίνεταί τις ποταμός, καὶ πάλιν ἀναδίδωσιν κατ' ἄλλον τόπον ὁ δὲ Ῥοδανὸς ποταμὸς ναυσιπέρατός ἐστιν.	128 However, there is nothing impossible about the existence of such places containing a quantity of water like lakes: only they cannot be big enough to produce the supposed effect. To think that they are is just as absurd as if one were to suppose that rivers drew all their water from the sources we see (for most rivers do flow from springs). So it is no more reasonable to suppose those lakes to contain the whole volume of water than these springs. That there exist such chasms and cavities in the earth we are taught by the rivers that are swallowed up. They are found in many parts of the earth: in the Peloponnesus, for instance, there are many such rivers in Arcadia. The reason is that Arcadia is mountainous and there are no channels from its valleys to the sea. So these places get full of water, and this, having no outlet, under the pressure of the water that is added above, finds a way out for itself underground. In Greece this kind of thing happens on quite a small scale, but the lake at the foot of the Caucasus, which the inhabitants of these parts call a sea, is considerable. Many great rivers fall into it and it has no visible outlet but issues below the earth off the land of the Coraxi about the so-called 'deeps of Pontus'. This is a place of unfathomable depth in the sea: at any rate no one has yet been able to find bottom there by sounding. At this spot, about three hundred stadia from land, there comes up sweet water over a large area, not all of it together but in three places. And in Liguria a river equal in size to the Rhodanus is swallowed up and appears again elsewhere: the Rhodanus being a navigable river.

Postquam philosophus determinavit de his quae generantur in alto ab exhalatione humida, hic determinat de his quae generantur in terra ex eadem materia, scilicet de fontibus et fluminibus. Et dividitur in partes duas:	123. After determining concerning things generated on high from the moist exhalation, the Philosopher here determines about things generated on earth from the same material — namely, about springs and rivers. It is divided into two parts:
in prima determinat de causa generationis fluviorum; in secunda de duratione eorum, ibi: non semper autem eadem loca et cetera.	In the first he determines concerning the cause of the generation of rivers; In the second concerning their duration (L. 17).
Circa primum tria facit. Primo dicit de quo est intentio. Et dicit quod est de ventis et omnibus quae ex ventis causantur, et de fluviis et de mari. De quibus hoc ordine dicetur, quod primo proponemus dubitationes ad nosipsos, et postea declarabimus veritatem ad nosipsos, et non ad alios: quia de talibus nihil accepimus dictum ab aliis, quod non quilibet possit dicere, sicut et circa alias materias contingit.	As to the first, he does three things: first, he states his intention [120] and says that the discussion is about winds and everything caused by winds, and about rivers and the sea. These will be treated in the following order: we shall propose problems of our own; then we shall declare the true answer to the problems to ourselves and not others: since on these matters we have received no opinions from others that anybody could not have conceived, unlike that which was the case in regard to the other matters.
Secundo ibi: sunt autem quidam etc., ponit opiniones quorundam de ventis. Et dicit quod quidam dixerunt quod corpus quod dicitur aer, dum fluit et movetur, est ventus; dum autem constat et inspissatur, est nubes et aqua; ac si eadem natura sit aquae, aeris et venti, et nihil aliud sit ventus quam aer et aqua. Et quia aer totus est unus, ideo quidam, volentes multum sapienter loqui, dixerunt quod non est nisi unus ventus; et quod videantur venti differre, hoc non est nisi ex differentia locorum ex quibus moventur. Quod est simile ac si dicerent quod omnes fluvii sunt unus fluvius, et quod omnis aqua est una: quod manifeste falsum est. Unde multitudo hominum, qui vulgariter et sine inquisitione philosophiae loquuntur de ventis, melius loquuntur quam isti, qui sic inquirendo erraverunt. Quia si hoc esset verum, quod omnes fluvii fluerent ex uno principio, et hoc etiam posset aliquo modo esse verum, quod omnes venti essent ex uno principio: sed de ventis etiam, sicut de fluviis, manifestum est quod id quod dixerunt, leviter et mendaciter dixerunt.	124. Secondly [121], he presents the opinions of certain others about winds. And he says that some have declared that the body called "air," when it flows along and is in motion, is wind; but when it halts and condenses, it is cloud and water — as though the natures of water, air and wind were identical, and wind were nothing more than air and water. And because the whole of air is one, some, wishing to speak very wisely, have asserted that there is but one wind, and that if winds seem to differ, it is only because of the different places whence they move. This is like saying that all rivers are one river, and that all water is one: which is plainly false. Hence the generality of mankind, who speak as do the uneducated and without philosophic enquiry about the winds, speak with more truth than these, who in such an inquiry erred. For if it were true that all rivers flowed from one source, then it could also be somehow true that all winds were from one source: but it is plain that, for winds as well as for rivers, what they said is frivolously and deceitfully said.
Opportunum est autem de hoc considerare in proprio tractatu, quid est ventus, et quomodo generatur, et quid movet ipsum, et unde est principium ventorum; et utrum oporteat accipere ventum fluentem sicut ex aliquo vase, qui tandiu fluat donec illud evacuetur, ac si esset emissum ab aliquo utre, ut fabulatur Homerus; aut non est ex uno principio sed ex multis, sicut pictores pingunt diversos ventos emittentes ex seipsis principium flatuum.	It is appropriate to discuss in a tract proper to it what wind is, and how it is generated, and what moves it, and from what do winds derive their source, and whether we must consider the wind as though flowing from some receptacle, and continuing to flow until it is emptied, as though wind were squeezed out of a wineskin as Homer's fable pretended; or whether it comes, not from one, but from many sources, as the painters depict the various winds puffing from out of themselves the source of breezes.
Tertio ibi: similiter autem de generatione etc., inducit similes opiniones de generatione fluviorum: propter hoc enim induxerat quod dictum est de ventis. Et circa hoc tria facit:	125. Thirdly [122], he presents like opinions about the generation of rivers: this was the reason he introduced what he said concerning winds. About this he does three things:
primo ponit quorundam falsam opinionem; secundo reprobat eam, ibi: quamvis manifestum etc.; tertio excludit quandam rationem ipsorum, ibi: non solum sed et talia et cetera.	First, he presents the false opinion of certain ones, at 125; Secondly, he rejects it, at 126, Thirdly, he rejects a certain argument of their, at 130.
Dicit ergo primo quod similiter videtur quibusdam se habere de generatione fluviorum, sicut dictum est de generatione ventorum. Dicunt enim quod, cum aqua elevatur a terra per vaporationem, et iterum fluit deorsum, congregatur sub terra, et sic fluit ad generationem fontium et fluviorum; sicut si intelligantur exire ex aliquo magno ventre, idest ex aliqua magna voragine, ubi sit congregata multa aqua; sive ita sit quod omnes fluvii fluant ex uno principio tali, sive ex diversis talibus principiis diversi fluvii fluant. Et secundum hoc, aqua non generatur sub terra de novo ad fluxum fontium et fluviorum; sed illa quae prius fuit collecta in praedicta receptacula, est principium multitudinis aquarum et fluviorum.	He says therefore first [122], that to some, the same things seem to be true of the generation of rivers as was said of the generation of winds. For they say that when water is raised aloft through evaporation and then re-descends, it collects under the earth and thus flows on to generate springs and rivers. It is as if they were understood to emerge from some "great womb," i.e., from some large depth where a great amount of water is gathered. It makes no difference to their theory whether all rivers flow from one such source or various rivers from various sources of this sort. According to this theory water is not newly generated under the earth to cause the flow of springs and rivers: what happens is that the water previously collected in the aforesaid receptacles is the source of the amount of waters and rivers.
Et huius signum dicebant esse, quod in hieme est maior fluxus fluviorum quam in aestate. Et hinc assignant causam quare quidam fluviorum sunt perpetui, et quidam non perpetui. Quando enim, propter magnitudinem voraginis, tanta aqua congregatur in hieme sub terra, ut sufficiat ad perpetuitatem fluvii, ita quod non deficiat aqua fluens priusquam iterum superveniat in nova hieme, tunc fluvius fit perpetuus usque in finem: si autem receptaculum sit parvum, tunc propter paucitatem aquae deficit origo fluvii, quasi evacuato vase, antequam iterum fluat aqua de caelo; et ideo fluvius non perenniter fluit.	And they said that a sign of this is the fact that in winter there is more river-flow than in summer. From this they assign the cause why some rivers are unceasing and some not. For when, because of the size of the depth, a sufficient amount of water gathers under the earth to assure continuity of flow, in such a way that the flowing water does not run out before returning again the next winter, then the river is made perpetual to the end. But if the reservoir is small, then, because of the smallness of the amount of water, the river's source runs dry (as an emptied vessel) before water again flows from the sky. That is why such a river does not flow perennially.
Deinde cum dicit: quamvis manifestum etc., improbat praedictam positionem quadrupliciter: primo quidem dicens quod, si aliquis velit prae oculis considerare multitudinem aquae quae continue fluit per fluvios per totum universum, excederet totam quantitatem terrae, vel parum ab ea deficeret, si oporteret esse aliquod receptaculum sub terra, vel unum vel plura, unde flumina fluerent. Et sic oporteret totam terram interius esse concavam, ad capiendam tantam multitudinem aquae; et hoc ipsum non sufficeret.	126. Then [123] he rejects this position for four reasons: First, he says that if one were to take into consideration the vast amount of water that continually flows through rivers in the entire world, the subterranean reservoir, or reservoirs, feeding these rivers, would have to be larger, or at least almost as large, as the earth. This would require that the whole interior of the earth be hollow, in order to hold such a vast amount of water; and even that would not be a sufficiently large container.
Hoc autem patet esse falsum. Cum enim terra naturaliter sit in medio, et naturaliter partes tendant ad medium, non potest dici quod terra sit tantum concava interius ad suscipiendam aquam; licet non sit inconveniens quod in multis locis terrae sint aliqua receptacula aquarum.	Now this is plainly false: for, since earth is by nature in the middle [center], and its parts naturally tend to the middle, it cannot be said that the earth is hollow enough within to hold the water — although it is not inadmissible that there be certain receptacles of water in many parts of the earth.
Secundo ibi: non solum sed et inconveniens etc., ponit secundam rationem. Et dicit quod inconveniens est, si quis non putet quod ex aere evaporato intra terram fiat aqua, propter eandem causam propter quam fit etiam supra terram in aere. Unde si supra terram in aere aer evaporatus propter frigiditatem condensatur in aquam, oportet putare quod etiam a frigiditate terrae hoc idem fiat. Et sic non solum aqua separatim existens in terra quasi in aliquo receptaculo, fluet per fluvios; sed continue infra terram generatur per infrigidationem vaporum, et haec effluet per fluvios.	127. Secondly [124], he gives a second argument and says that it is inconsistent for one not to suppose that water comes to be within the earth from evaporated air, for the same reason that it is produced above the earth in the air. Hence, if evaporated air is condensed into water in the air above the earth on account of coldness, one must believe that the same is produced by reason of the coldness of the earth. And so, not only water existing separated in the earth as in a reservoir, flows through rivers, but water is also being continually generated within the earth by the refrigeration of vapors, and this will flow out through rivers.
Sed quia posset aliquis dicere quod ex vaporibus infra terram generatur quaedam aqua, sed tota simul colligitur in aliquibus receptaculis, ex quibus fluvii fluunt, quod esset simile et quasi idem positioni praedictae, ideo tertio hoc excludit per quoddam signum, ibi: adhuc autem et cetera. Et dicit quod adhuc non est intelligendum tale esse principium fluviorum, quod aqua quidem generetur infra terram, sed existat ibi quotidie dum flumina fluunt, ac si essent quaedam stagna aquarum sub terra, ut quidam dicunt: sed oportet intelligere sic fieri intra terram, sicut fit supra terram. Supra terram enim, dum primo condensatur vapor, fiunt parvae guttae, quae adunantur cum aliis; et sic facile aqua fluens descendit cum quadam multitudine. Ita etiam fit infra terram: primo enim parvae guttae generantur; et sic principia fluviorum sunt quaedam scaturigines paulatim scaturientes in imo terrae.	128. But because someone could say that a certain water is generated within the earth from vapors, but that the whole is collected together into certain reservoirs, whence rivers flow, which theory would be similar to, and practically the same as, the previous position, therefore, thirdly, he rejects this by means of a sign at [125]. And he says that it is even not to be supposed that water indeed is generated within the earth but remains there from day to day while rivers flow, as though there were certain pools of water under the earth, as some say. But one must understand that things take place in the same way within the earth, as above the earth. For above the earth, when vapor is first being condensed, small drops form and coalesce with others and in this way the flowing water easily descends in a certain quantity. The same thing takes place within the earth: for first small drops are generated; and thus the sources of rivers are springs gushing little by little below the earth.
Et hoc manifestatur per opus: qui enim volunt ducere aquas, puta facientes puteos vel aliquid tale, colligunt aquas in locis infimis et defossis, ac si fieret quaedam resudatio terrae per aquam a locis excelsis ad infima. Et ex hoc apparet quod aqua guttatim profluit a terra ad generationem fluviorum et fontium; non autem ita quod infra terram sint loca quae sint quasi stagna aquarum actu existentium.	An indication of this is what is done — for people who wish to bring out water, e.g., who dig wells or the like, collect the water in low and excavated places, as though the earth perspired water from elevated areas to lower areas. From which it appears that water flows drop by drop from the earth to produce rivers and springs, rather than that in the earth are places acting as pools of actually existing water.
Quarto ibi: propter quod et rheumata etc., ponit aliud signum ad idem, sumptum ex naturali fluxu aquarum: nam praecedens signum fuit sumptum ex opere. Et dicit quod propter eandem causam rheumata, idest fluviorum fluxus, videntur esse ex montibus, et maximi fluvii fluunt ex maximis montibus; et fontes, ut plurimum, sunt vicini montibus et locis altis; sed in campestribus sunt pauci fontes separati a fluviis. Et hoc ideo est, quia loca montana et alta sunt sicut quaedam spongia spissa, propter soliditatem lapidum, ad eiiciendam aquam; et sunt suspensa, ad hoc quod aqua possit fluere; et sic producunt aquam in multis locis; et colligunt etiam aquam desuper complutam. Sed hoc secundum modicas partes, non tamen ita quod infra montes sint voragines in quibus congregatur aqua. Et ideo dicit quod colligunt aquam, quia suscipiunt magnam multitudinem aquae desuper advenientis per pluviam. Et ad hoc cooperatur figura montium: nam figura rotunda est capacissima figurarum.	129. Fourthly [126], he supports the same view with another sign, based on the natural flow of waters: for the previous sign was based on a [human] work. And he says that for the same reason, the "discharge," i.e., the flow of rivers, seems to be from the mountains, and the largest rivers flow from the largest mountains; moreover, most springs are close to mountains and high places, whereas on the plains there are few springs apart from rivers. The reason is that mountainous and high places are like certain thick sponges (because the rocks are hard) as to ejecting water; and they are suspended [elevated], so that the water can flow: consequently, they produce water in many places and also collect water that comes down from above as rain. But this occurs in small sections of the mountains and not in the sense that within the mountains there are depths in which water is gathered. That is why he says that they collect water, for they receive a great abundance of water coming as rainfall. The shape of mountains is well-adapted for this, for a round shape is the most capacious of shapes.
Nihil autem differt ad recipiendam multitudinem aquae, an circumferentia sit disposita supreme secundum concavitatem, an secundum convexam gibbositatem: quia utroque modo aequalem quantitatem capiet. Unde licet montes non sint positi secundum concavitatem, sed magis secundum gibbositatem, tamen multitudinem aquarum recipere possunt. Et non solum colligunt multitudinem aquarum ut aliunde receptam, propter figuram, sed etiam producunt eam ut interius generatam propter frigiditatem: quia vaporem resolutum a terra, et ascendentem propter caliditatem innatam, frigiditas terrae infra terram partim coagulat, et sic iterum condensat ipsum in aquam. Et ideo, ut dictum est, maximi fluviorum fluunt ex maximis montibus.	So far as holding a great amount of water is concerned, it makes no difference whether the circumference is disposed above in a concave way, or according to a convex swelling — for in either case the capacity is equal. Hence, although mountains are not concave, but more convex, nevertheless they can receive a vast amount of water. And they not only hold a great amount of water as received from elsewhere, because of their shape, but also bring it forth as water born within because of the cold: for the vapor of earth, drawn out of the earth, and rising because of its inherent warmth, is coagulated within the earth by the coldness of the earth, so that it is again condensed into water. And that is why, as was said, the largest rivers flow from the largest mountains.
Et hoc manifestum est, si quis consideret circularem descriptionem terrae: qui enim sic descripserunt terram, vel ipsi viderunt flumina et regiones, vel ab aliis inquisiverunt. Ponit ergo exemplum primo quidem in Asia de Parnaso, qui est ad ortum hiemalem, et de Caucaso, qui est ad ortum aestivalem, ex quibus, cum sint maximi montes, multi et maximi fluvii oriuntur; in Europa autem de monte Pyrenaeo, qui est ad occasum aequinoctialem, et de quibusdam aliis montibus qui sunt ad Septentrionem in Scythia, ex quibus etiam fiunt magna flumina; et in Africa, sive in Libya, de quibusdam aliis magnis montibus, ex quibus alia magna flumina fluunt. Et similiter dicit esse de aliis montibus et fluviis: et quod, quicumque alii fluvii fluunt ex paludibus, paludes istae sunt positae prope montes, et sic in idem redit. Et sic, exemplis positis, concludit propositum, dicens: quod quidem igitur non oportet et cetera. Et repetit quod supra dictum est: unde planum est in littera.	And this is plain, if one examines a traveler's description of the earth: for those who so described the earth have either themselves seen the rivers and regions, or learned of them from others. He therefore presents first the example of Parnassus which is in Asia at the winter rising [i.e., the southeast], and of the Caucasus, at the summer rising [north east]: since these are very large mountains, many and very large rivers rise from them. In Europe he gives the example of the Pyrenees located in the equinoctial setting [equatorial west], as well as of certain other mountains, which lie toward the north in Scythia: large rivers rise from them too. Then in Africa or in Libya he gives the example of certain other large mountains from which other great rivers flow. And he says the same is true of other mountains and rivers, and that, whatever other rivers flow from marshes, these marshes are located near mountains; and thus is the same thing true. — From these examples, therefore, he concludes to his proposition [127] and repeats what was said above: thus the text is plain.
Deinde cum dicit: non solum sed et talia etc., excludit rationem ponentium praedictam positionem. Et dicit quod non est inconveniens quod inveniantur aliqua loca habentia actu multitudinem aquae, ac si essent stagna; sed non ad tantum hoc valet, ut ex hoc possit accidere fluxus fluviorum. Non enim magis possumus dicere quod aquae, si quae collectae inveniuntur sub terra vel in montibus, contineant totam aquam fluviorum, quam si quis dicat quod fontes qui manifeste apparent extra terram, totam aquam fluviorum actu contineant: plurimi enim fluviorum fluunt ex fontibus (quod dicit propter hoc quod aliqui fluunt ex paludibus, ut dictum est). Unde simile est putare quod contineant totum corpus aquae quae fluit per flumina, illae collectiones subterraneae, ut existimare quod ipsam contineant istae collectiones aquarum quae inveniuntur extra terram in fontibus. Unde, cum de fontibus manifestum sit hoc esse falsum, per simile potest cognosci hoc etiam esse falsum de collectionibus aquarum quae sunt sub terra. Quod autem sint tales collectiones aquarum sub terra, manifestum esse potest per hoc quod multa flumina absorbentur a terra. Et hoc manifestat per multa exempla: et est planum in littera.	130. Then [128] he refutes the argument of those who posit the opinion under discussion. And he says that it is not inadmissible that places should be found actually containing a vast amount of water after the manner of lakes: but this is not sufficient to account for the flow of rivers. For we can no more say that the waters which may exist collected under the earth or in the mountains, contain all the water of rivers, than we can say that the springs, which plainly appear outside the earth, actually contain all the water of rivers: for most rivers flow from springs (which he says, because some flow from marshes, as has been said). Hence to think that those subterranean collections of water contain the entire body of waters that flow through rivers is like supposing that those collections of water found outside the earth in springs contain all the water found in rivers. Hence, since it is plainly false to suppose this of the springs we can see, then it can be known by analogy that it is also false to suppose it of the collections of water under the earth. But that such collections of water do exist under the earth can be made manifest by the fact that many streams are absorbed by the earth. This he explains with many examples that are plain in the text.

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Lecture 17 The duration and change of rivers
Chapter 14
οὐκ αἰεὶ δ' οἱ αὐτοὶ τόποι τῆς γῆς οὔτ' ἔνυγροί εἰσιν οὔτε ξηροί, ἀλλὰ μεταβάλλουσιν κατὰ τὰς τῶν ποταμῶν γενέσεις καὶ τὰς ἀπολείψεις διὸ καὶ τὰ περὶ τὴν ἤπειρον μεταβάλλει καὶ τὴν θάλατταν, καὶ οὐκ αἰεὶ τὰ μὲν γῆ τὰ δὲ θάλαττα διατελεῖ πάντα τὸν χρόνον, ἀλλὰ γίγνεται θάλαττα μὲν ὅπου χέρσος, ἔνθα δὲ νῦν θάλαττα, πάλιν ἐνταῦθα γῆ. κατὰ μέντοι τινὰ τάξιν νομίζειν χρὴ ταῦτα γίγνεσθαι καὶ περίοδον.	129 The same parts of the earth are not always moist or dry, but they change according as rivers come into existence and dry up. And so the relation of land to sea changes too and a place does not always remain land or sea throughout all time, but where there was dry land there comes to be sea, and where there is now sea, there one day comes to be dry land. But we must suppose these changes to follow some order and cycle.
ἀρχὴ δὲ τούτων καὶ αἴτιον ὅτι καὶ τῆς γῆς τὰ ἐντός, ὥσπερ τὰ σώματα τῶν φυτῶν καὶ ζῴων, ἀκμὴν ἔχει καὶ γῆρας. πλὴν ἐκείνοις μὲν οὐ κατὰ μέρος ταῦτα συμβαίνει πάσχειν, ἀλλ' ἅμα πᾶν ἀκμάζειν καὶ φθίνειν ἀναγκαῖον τῇ δὲ γῇ τοῦτο γίγνεται κατὰ μέρος διὰ ψύξιν καὶ θερμότητα. ταῦτα μὲν οὖν αὔξεται καὶ φθίνει διὰ τὸν ἥλιον καὶ τὴν περιφοράν, διὰ δὲ ταῦτα καὶ τὴν δύναμιν τὰ μέρη τῆς γῆς λαμβάνει διαφέρουσαν, ὥστε μέχρι τινὸς ἔνυδρα δύναται διαμένειν, εἶτα ξηραίνεται καὶ γηράσκει πάλιν ἕτεροι δὲ τόποι βιώσκονται καὶ ἔνυδροι γίγνονται κατὰ μέρος. ἀνάγκη δὲ τῶν μὲν τόπων γιγνομένων (351b.) ξηροτέρων τὰς πηγὰς ἀφανίζεσθαι, τούτων δὲ συμβαινόντων τοὺς ποταμοὺς πρῶτον μὲν ἐκ μεγάλων μικρούς, εἶτα τέλος γίγνεσθαι ξηρούς, τῶν δὲ ποταμῶν μεθισταμένων καὶ ἔνθεν μὲν ἀφανιζομένων ἐν ἄλλοις δ' ἀνάλογον γιγνομένων μεταβάλλειν τὴν θάλατταν ὅπου μὲν γὰρ ἐξωθουμένη ὑπὸ τῶν ποταμῶν ἐπλεόναζεν, ἀπιοῦσαν ξηρὰν ποιεῖν ἀναγκαῖον, ὅπου δὲ τοῖς ῥεύμασιν πληθύουσα ἐξηραίνετο προσχουμένη, πάλιν ἐνταῦθα λιμνάζειν.	130 The principle and cause of these changes is that the interior of the earth grows and decays, like the bodies of plants and animals. Only in the case of these latter the process does not go on by parts, but each of them necessarily grows or decays as a whole, whereas it does go on by parts in the case of the earth. Here the causes are cold and heat, which increase and diminish on account of the sun and its course. It is owing to them that the parts of the earth come to have a different character, that some parts remain moist for a certain time, and then dry up and grow old, while other parts in their turn are filled with life and moisture. Now when places become drier the springs necessarily give out, and when this happens the rivers first decrease in size and then finally become dry; and when rivers change and disappear in one part and come into existence correspondingly in another, the sea must needs be affected. If the sea was once pushed out by rivers and encroached upon the land anywhere, it necessarily leaves that place dry when it recedes; again, if the dry land has encroached on the sea at all by a process of silting set up by the rivers when at their full, the time must come when this place will be flooded again.
ἀλλὰ διὰ τὸ γίγνεσθαι πᾶσαν τὴν φυσικὴν περὶ τὴν γῆν γένεσιν ἐκ προσαγωγῆς καὶ ἐν χρόνοις παμμήκεσι πρὸς τὴν ἡμετέραν ζωήν, λανθάνει ταῦτα γιγνόμενα, καὶ πρότερον ὅλων τῶν ἐθνῶν ἀπώλειαι γίγνονται καὶ φθοραὶ πρὶν μνημονευθῆναι τὴν τούτων μεταβολὴν ἐξ ἀρχῆς εἰς τέλος. μέγισται μὲν οὖν φθοραὶ γίγνονται καὶ τάχισται ἐν τοῖς πολέμοις, ἄλλαι δὲ νόσοις, αἱ δὲ ἀφορίαις, καὶ ταύταις αἱ μὲν μεγάλαι αἱ δὲ κατὰ μικρόν, ὥστε λανθάνουσι τῶν γε τοιούτων ἐθνῶν καὶ αἱ μεταναστάσεις διὰ τὸ τοὺς μὲν λείπειν τὰς χώρας, τοὺς δὲ ὑπομένειν μέχρι τούτου μέχριπερ ἂν μηκέτι δύνηται τρέφειν ἡ χώρα πλῆθος μηδέν. ἀπὸ τῆς πρώτης οὖν ἀπολείψεως εἰς τὴν ὑστέραν εἰκὸς γίγνεσθαι μακροὺς χρόνους, ὥστε μηδένα μνημονεύειν, ἀλλὰ σῳζομένων ἔτι τῶν ὑπομενόντων ἐπιλελῆσθαι διὰ χρόνου πλῆθος. τὸν αὐτὸν δὲ τρόπον χρὴ νομίζειν καὶ τοὺς κατοικισμοὺς λανθάνειν πότε πρῶτον ἐγένοντο τοῖς ἔθνεσιν ἑκάστοις εἰς τὰ μεταβάλλοντα καὶ γιγνόμενα ξηρὰ ἐξ ἑλωδῶν καὶ ἐνύδρων καὶ γὰρ ἐνταῦθα κατὰ μικρὸν ἐν πολλῷ γίγνεται χρόνῳ ἡ ἐπίδοσις, ὥστε μὴ μνημονεύειν τίνες πρῶτοι καὶ πότε καὶ πῶς ἐχόντων ἦλθον τῶν τόπων, οἷον συμβέβηκεν καὶ τὰ περὶ Αἴγυπτον καὶ γὰρ οὗτος ἀεὶ ξηρότερος ὁ τόπος φαίνεται γιγνόμενος καὶ πᾶσα ἡ χώρα τοῦ ποταμοῦ πρόσχωσις οὖσα τοῦ Νείλου, διὰ δὲ τὸ κατὰ μικρὸν ξηραινομένων τῶν ἑλῶν τοὺς πλησίον εἰσοικίζεσθαι τὸ τοῦ χρόνου μῆκος ἀφῄρηται τὴν ἀρχήν. φαίνεται οὖν καὶ τὰ στόματα πάντα, πλὴν ἑνὸς τοῦ Κανωβικοῦ, χειροποίητα καὶ οὐ τοῦ ποταμοῦ ὄντα, καὶ τὸ ἀρχαῖον ἡ Αἴγυπτος Θῆβαι καλούμεναι. δηλοῖ δὲ καὶ Ὅμηρος, οὕτως πρόσφατος ὢν ὡς εἰπεῖν πρὸς τὰς τοιαύτας μεταβολάς ἐκείνου γὰρ τοῦ τόπου (352a.) ποιεῖται μνείαν ὡς οὔπω Μέμφιος οὔσης ἢ ὅλως ἢ οὐ τηλικαύτης. τοῦτο δ' εἰκὸς οὕτω συμβαίνειν οἱ γὰρ κάτωθεν τόποι τῶν ἄνωθεν ὕστερον ᾠκίσθησαν ἑλώδεις γὰρ ἐπὶ πλείω χρόνον ἀναγκαῖον εἶναι τοὺς ἐγγύτερον τῆς προσχώσεως διὰ τὸ λιμνάζειν ἐν τοῖς ἐσχάτοις ἀεὶ μᾶλλον. μεταβάλλει δὲ τοῦτο καὶ πάλιν εὐθενεῖ ξηραινόμενοι γὰρ οἱ τόποι ἔρχονται εἰς τὸ καλῶς ἔχειν, οἱ δὲ πρότερον εὐκραεῖς ὑπερξηραινόμενοί ποτε γίγνονται χείρους. ὅπερ συμβέβηκε τῆς Ἑλλάδος καὶ περὶ τὴν Ἀργείων καὶ Μυκηναίων χώραν ἐπὶ μὲν γὰρ τῶν Τρωικῶν ἡ μὲν Ἀργεία διὰ τὸ ἑλώδης εἶναι ὀλίγους ἐδύνατο τρέφειν, ἡ δὲ Μυκηναία καλῶς εἶχεν (διὸ ἐντιμοτέρα ἦν), νῦν δὲ τοὐναντίον διὰ τὴν προειρημένην αἰτίαν ἡ μὲν γὰρ ἀργὴ γέγονεν καὶ ξηρὰ πάμπαν, τῆς δὲ τὰ τότε διὰ τὸ λιμνάζειν ἀργὰ νῦν χρήσιμα γέγονεν. ὥσπερ οὖν ἐπὶ τούτου τοῦ τόπου συμβέβηκεν ὄντος μικροῦ, ταὐτὸ δεῖ νομίζειν τοῦτο συμβαίνειν καὶ περὶ μεγάλους τόπους καὶ χώρας ὅλας.	131 But the whole vital process of the earth takes place so gradually and in periods of time which are so immense compared with the length of our life, that these changes are not observed, and before their course can be recorded from beginning to end whole nations perish and are destroyed. Of such destructions the most utter and sudden are due to wars; but pestilence or famine cause them too. Famines, again, are either sudden and severe or else gradual. In the latter case the disappearance of a nation is not noticed because some leave the country while others remain; and this goes on until the land is unable to maintain any inhabitants at all. So a long period of time is likely to elapse from the first departure to the last, and no one remembers and the lapse of time destroys all record even before the last inhabitants have disappeared. In the same way a nation must be supposed to lose account of the time when it first settled in a land that was changing from a marshy and watery state and becoming dry. Here, too, the change is gradual and lasts a long time and men do not remember who came first, or when, or what the land was like when they came. This has been the case with Egypt. Here it is obvious that the land is continually getting drier and that the whole country is a deposit of the river Nile. But because the neighbouring peoples settled in the land gradually as the marshes dried, the lapse of time has hidden the beginning of the process. However, all the mouths of the Nile, with the single exception of that at Canopus, are obviously artificial and not natural. And Egypt was nothing more than what is called Thebes, as Homer, too, shows, modern though he is in relation to such changes. For Thebes is the place that he mentions; which implies that Memphis did not yet exist, or at any rate was not as important as it is now. That this should be so is natural, since the lower land came to be inhabited later than that which lay higher. For the parts that lie nearer to the place where the river is depositing the silt are necessarily marshy for a longer time since the water always lies most in the newly formed land. But in time this land changes its character, and in its turn enjoys a period of prosperity. For these places dry up and come to be in good condition while the places that were formerly well-tempered some day grow excessively dry and deteriorate. This happened to the land of Argos and Mycenae in Greece. In the time of the Trojan wars the Argive land was marshy and could only support a small population, whereas the land of Mycenae was in good condition (and for this reason Mycenae was the superior). But now the opposite is the case, for the reason we have mentioned: the land of Mycenae has become completely dry and barren, while the Argive land that was formerly barren owing to the water has now become fruitful. Now the same process that has taken place in this small district must be supposed to be going on over whole countries and on a large scale.
οἱ μὲν οὖν βλέποντες ἐπὶ μικρὸν αἰτίαν οἴονται τῶν τοιούτων εἶναι παθημάτων τὴν τοῦ ὅλου μεταβολὴν ὡς γιγνομένου τοῦ οὐρανοῦ διὸ καὶ τὴν θάλατταν ἐλάττω γίγνεσθαί φασιν ὡς ξηραινομένην, ὅτι πλείους φαίνονται τόποι τοῦτο πεπονθότες νῦν ἢ πρότερον. ἔστιν δὲ τούτων τὸ μὲν ἀληθὲς τὸ δ' οὐκ ἀληθές πλείους μὲν γάρ εἰσιν οἱ πρότερον ἔνυδροι νῦν δὲ χερσεύοντες, οὐ μὴν ἀλλὰ καὶ τοὐναντίον πολλαχῇ γὰρ σκοποῦντες εὑρήσουσιν ἐπεληλυθυῖαν τὴν θάλατταν. ἀλλὰ τούτου τὴν αἰτίαν οὐ τὴν τοῦ κόσμου γένεσιν οἴεσθαι χρή γελοῖον γὰρ διὰ μικρὰς καὶ ἀκαριαίας μεταβολὰς κινεῖν τὸ πᾶν, ὁ δὲ τῆς γῆς ὄγκος καὶ τὸ μέγεθος οὐδέν ἐστι δή που πρὸς τὸν ὅλον οὐρανόν	132 Men whose outlook is narrow suppose the cause of such events to be change in the universe, in the sense of a coming to be of the world as a whole. Hence they say that the sea being dried up and is growing less, because this is observed to have happened in more places now than formerly. But this is only partially true. It is true that many places are now dry, that formerly were covered with water. But the opposite is true too: for if they look they will find that there are many places where the sea has invaded the land. But we must not suppose that the cause of this is that the world is in process of becoming. For it is absurd to make the universe to be in process because of small and trifling changes, when the bulk and size of the earth are surely as nothing in comparison with the whole world.
ἀλλὰ πάντων τούτων αἴτιον ὑποληπτέον ὅτι γίγνεται διὰ χρόνων εἱμαρμένων, οἷον ἐν ταῖς κατ' ἐνιαυτὸν ὥραις χειμών, οὕτως περιόδου τινὸς μεγάλης μέγας χειμὼν καὶ ὑπερβολὴ ὄμβρων. αὕτη δὲ οὐκ ἀεὶ κατὰ τοὺς αὐτοὺς τόπους, ἀλλ' ὥσπερ ὁ καλούμενος ἐπὶ Δευκαλίωνος κατακλυσμός καὶ γὰρ οὗτος περὶ τὸν Ἑλληνικὸν ἐγένετο τόπον μάλιστα, καὶ τούτου περὶ τὴν Ἑλλάδα τὴν ἀρχαίαν. αὕτη δ' ἐστὶν ἡ περὶ Δωδώνην καὶ τὸν Ἀχελῷον (352b.) οὗτος γὰρ πολλαχοῦ τὸ ῥεῦμα μεταβέβληκεν ᾤκουν γὰρ οἱ Σελλοὶ ἐνταῦθα καὶ οἱ καλούμενοι τότε μὲν Γραικοὶ νῦν δ' Ἕλληνες.	133 Rather we must take the cause of all these changes to be that, just as winter occurs in the seasons of the year, so in determined periods there comes a great winter of a great year and with it excess of rain. But this excess does not always occur in the same place. The deluge in the time of Deucalion, for instance, took place chiefly in the Greek world and in it especially about ancient Hellas, the country about Dodona and the Achelous, a river which has often changed its course. Here the Selli dwelt and those who were formerly called Graeci and now Hellenes.
ὅταν οὖν γένηται τοιαύτη ὑπερβολὴ ὄμβρων, νομίζειν χρὴ ἐπὶ πολὺν χρόνον διαρκεῖν, καὶ ὥσπερ νῦν τοῦ ἀενάους εἶναί τινας τῶν ποταμῶν τοὺς δὲ μὴ οἱ μέν φασιν αἴτιον εἶναι τὸ μέγεθος τῶν ὑπὸ γῆς χασμάτων, ἡμεῖς δὲ τὸ μέγεθος τῶν ὑψηλῶν τόπων καὶ τὴν πυκνότητα καὶ ψυχρότητα αὐτῶν (οὗτοι γὰρ πλεῖστον καὶ δέχονται ὕδωρ καὶ στέγουσιν καὶ ποιοῦσιν ὅσοις δὲ μικραὶ αἱ ἐπικρεμάμεναι τῶν ὀρῶν συστάσεις ἢ σομφαὶ καὶ λιθώδεις καὶ ἀργιλώδεις, τούτους δὲ προαπολείπειν), οὕτως οἴεσθαι δεῖν τότε, ἐν οἷς ἂν γένηται ἡ τοιαύτη τοῦ ὑγροῦ φορά, οἷον ἀενάους ποιεῖν τὰς ὑγρότητας τῶν τόπων μᾶλλον. τῷ χρόνῳ δὲ ταῦτα ξηραίνεται γιγνόμενα μᾶλλον, θάτερα δ' ἐλάττω τὰ ἔφυδρα, ἕως ἂν ἔλθῃ πάλιν ἡ καταβολὴ τῆς περιόδου τῆς αὐτῆς. ἐπεὶ δ' ἀνάγκη τοῦ ὅλου γίγνεσθαι μέν τινα μεταβολήν, μὴ μέντοι γένεσιν καὶ φθοράν, εἴπερ μένει τὸ πᾶν, ἀνάγκη, καθάπερ ἡμεῖς λέγομεν, μὴ τοὺς αὐτοὺς ἀεὶ τόπους ὑγρούς τ' εἶναι θαλάττῃ καὶ ποταμοῖς καὶ ξηρούς.	134 When, therefore, such an excess of rain occurs we must suppose that it suffices for a long time. We have seen that some say that the size of the subterranean cavities is what makes some rivers perennial and others not, whereas we maintain that the size of the mountains is the cause, and their density and coldness; for great, dense, and cold mountains catch and keep and create most water: whereas if the mountains that overhang the sources of rivers are small or porous and stony and clayey, these rivers run dry earlier. We must recognize the same kind of thing in this case too. Where such abundance of rain falls in the great winter it tends to make the moisture of those places almost everlasting. But as time goes on places of the latter type dry up more, while those of the former, moist type, do so less: until at last the beginning of the same cycle returns. Since there is necessarily some change in the whole world, but not in the way of coming into existence or perishing (for the universe is permanent), it must be, as we say, that the same places are not for ever moist through the presence of sea and rivers, nor for ever dry.
δηλοῖ δὲ τὸ γιγνόμενον οὓς γάρ φαμεν ἀρχαιοτάτους εἶναι τῶν ἀνθρώπων Αἰγυπτίους, τούτων ἡ χώρα πᾶσα γεγονυῖα φαίνεται καὶ οὖσα τοῦ ποταμοῦ ἔργον. καὶ τοῦτο κατά τε τὴν χώραν αὐτὴν ὁρῶντι δῆλόν ἐστιν, καὶ τὰ περὶ τὴν ἐρυθρὰν θάλατταν τεκμήριον ἱκανόν ταύτην γὰρ τῶν βασιλέων τις ἐπειράθη διορύττειν (οὐ γὰρ μικρὰς εἶχεν ἂν αὐτοῖς ὠφελείας πλωτὸς πᾶς ὁ τόπος γενόμενος λέγεται δὲ πρῶτος Σέσωστρις ἐγχειρῆσαι τῶν παλαιῶν), ἀλλ' εὗρεν ὑψηλοτέραν οὖσαν τὴν θάλατταν τῆς γῆς διὸ ἐκεῖνός τε πρότερον καὶ Δαρεῖος ὕστερον ἐπαύσατο διορύττων, ὅπως μὴ διαφθαρῇ τὸ ῥεῦμα τοῦ ποταμοῦ συμμιγείσης τῆς θαλάττης. φανερὸν οὖν ὅτι θάλαττα πάντα μία ταύτῃ συνεχὴς ἦν. διὸ καὶ τὰ περὶ τὴν Λιβύην τὴν Ἀμμωνίαν χώραν ταπεινότερα φαίνεται καὶ κοιλότερα παρὰ λόγον τῆς κάτωθεν χώρας δῆλον γὰρ ὡς ἐγχώσεως μὲν γενομένης ἐγένοντο λίμναι καὶ χέρσος, χρόνου δὲ γενομένου τὸ ἐναπολειφθὲν καὶ λιμνάσαν ὕδωρ (353a.) ξηρανθέν ἐστιν ἤδη φροῦδον. ἀλλὰ μὴν καὶ τὰ περὶ τὴν Μαιῶτιν λίμνην ἐπιδέδωκε τῇ προσχώσει τῶν ποταμῶν τοσοῦτον, ὥστε πολλῷ ἐλάττω μεγέθει πλοῖα νῦν εἰσπλεῖν πρὸς τὴν ἐργασίαν ἢ ἔτος ἑξηκοστόν ὥστε ἐκ τούτου ῥᾴδιον ἀναλογίσασθαι ὅτι καὶ τὸ πρῶτον, ὥσπερ αἱ πολλαὶ τῶν λιμνῶν, καὶ αὕτη ἔργον ἐστὶ τῶν ποταμῶν, καὶ τὸ τελευταῖον πᾶσαν ἀνάγκη γενέσθαι ξηράν. ἔτι δὲ ὁ Βόσπορος ἀεὶ μὲν ῥεῖ διὰ τὸ προσχοῦσθαι, καὶ ἔστιν ἔτι ταῦτα καὶ τοῖς ὄμμασιν ἰδεῖν ὅν τινα συμβαίνει τρόπον ὅτε γὰρ ἀπὸ τῆς Ἀσίας ᾐόνα ποιήσειεν ὁ ῥοῦς, τὸ ὄπισθεν λίμνη ἐγίγνετο μικρὰ τὸ πρῶτον, εἶτ' ἐξηράνθη ἄν, μετὰ δὲ τοῦτο ἄλλη ἡ ἀπὸ ταύτης ᾐών, καὶ λίμνη ἀπὸ ταύτης καὶ τοῦτο ἀεὶ οὕτως συνέβαινεν ὁμοίως τούτου δὲ γιγνομένου πολλάκις ἀνάγκη χρόνου προϊόντος ὥσπερ ποταμὸν γενέσθαι, τέλος δὲ καὶ τοῦτον ξηρόν.	135 And the facts prove this. The whole land of the Egyptians, whom we take to be the most ancient of men, has evidently gradually come into existence and been produced by the river. This is clear from an observation of the country, and the facts about the Red Sea suffice to prove it too. One of their kings tried to make a canal to it (for it would have been of no little advantage to them for the whole region to have become navigable; Sesostris is said to have been the first of the ancient kings to try), but he found that the sea was higher than the land. So he first, and Darius afterwards, stopped making the canal, lest the sea should mix with the river water and spoil it. So it is clear that all this part was once unbroken sea. For the same reason Libya—the country of Ammon—is, strangely enough, lower and hollower than the land to the seaward of it. For it is clear that a barrier of silt was formed and after it lakes and dry land, but in course of time the water that was left behind in the lakes dried up and is now all gone. Again the silting up of the lake Maeotis by the rivers has advanced so much that the limit to the size of the ships which can now sail into it to trade is much lower than it was sixty years ago. Hence it is easy to infer that it, too, like most lakes, was originally produced by the rivers and that it must end by drying up entirely. Again, this process of silting up causes a continuous current through the Bosporus; and in this case we can directly observe the nature of the process. Whenever the current from the Asiatic shore threw up a sandbank, there first formed a small lake behind it. Later it dried up and a second sandbank formed in front of the first and a second lake. This process went on uniformly and without interruption. Now when this has been repeated often enough, in the course of time the strait must become like a river, and in the end the river itself must dry up.
φανερὸν τοίνυν, ἐπεὶ ὅ τε χρόνος οὐχ ὑπολείψει καὶ τὸ ὅλον ἀίδιον, ὅτι οὔτε ὁ Τάναϊς οὔτε ὁ Νεῖλος ἀεὶ ἔρρει, ἀλλ' ἦν ποτε ξηρὸς ὁ τόπος ὅθεν ῥέουσιν τὸ γὰρ ἔργον ἔχει αὐτῶν πέρας, ὁ δὲ χρόνος οὐκ ἔχει. ὁμοίως δὲ τοῦτο καὶ ἐπὶ τῶν ἄλλων ἁρμόσει ποταμῶν λέγειν. ἀλλὰ μὴν εἴπερ καὶ οἱ ποταμοὶ γίγνονται καὶ φθείρονται καὶ μὴ ἀεὶ οἱ αὐτοὶ τόποι τῆς γῆς ἔνυδροι, καὶ τὴν θάλατταν ἀνάγκη μεταβάλλειν ὁμοίως. τῆς δὲ θαλάττης τὰ μὲν ἀπολειπούσης τὰ δ' ἐπιούσης ἀεὶ φανερὸν ὅτι τῆς πάσης γῆς οὐκ ἀεὶ τὰ αὐτὰ τὰ μέν ἐστιν θάλαττα τὰ δ' ἤπειρος, ἀλλὰ μεταβάλλει τῷ χρόνῳ πάντα.	136 So it is clear, since there will be no end to time and the world is eternal, that neither the Tanais nor the Nile has always been flowing, but that the region whence they flow was once dry: for their effect may be fulfilled, but time cannot. And this will be equally true of all other rivers. But if rivers come into existence and perish and the same parts of the earth were not always moist, the sea must needs change correspondingly. And if the sea is always advancing in one place and receding in another it is clear that the same parts of the whole earth are not always either sea or land, but that all this changes in course of time.
διότι μὲν οὖν οὐκ ἀεὶ ταὐτὰ οὔτε χερσεύει τῆς γῆς οὔτε πλωτά ἐστιν, καὶ διὰ τίν' αἰτίαν ταῦτα συμβαίνει, εἴρηται ὁμοίως δὲ καὶ διὰ τί οἱ μὲν ἀέναοι οἱ δ' οὒ τῶν ποταμῶν εἰσιν.	137 So we have explained that the same parts of the earth are not always land or sea and why that is so: and also why some rivers are perennial and others not.

Postquam philosophus ostendit causam generationis fluviorum, hic determinat de duratione eorum. Et circa hoc duo facit.	131. After showing the cause of the generation of rivers, the Philosopher here determines about their duration. About this he does two things:
Primo ponit opinionem suam circa hoc. Et dicit quod non semper eadem loca terrae sunt aquosa vel arida; sed hoc permutatur secundum quod fluvii generantur de novo vel deficiunt. Propter quam causam fit permutatio circa terram, ut quae nunc est arida, aliquando fiat mare, et e converso; et non semper in una et eadem parte terrae sint mare vel terra sicca. Sed hoc non accidit casu, sed secundum quendam ordinem, et secundum aliquam circulationem caeli; sicut et omnes transmutationes quae fiunt in istis inferioribus, ordinantur secundum motum caeli.	First, he presents his own opinion [129] and says that the same parts of the earth are not always moist or dry, but they vary according as rivers are newly formed or decay. As a result, changes occur affecting the earth, so that what is now dry, later becomes a sea and vice versa; and sea or dry land are not always present in the same part of the earth. But this takes place, not by chance, but according to a certain order and according to a certain turning of the heavens, just as all changes taking place in these lower regions are regulated according to the movement of the heaven.
Secundo ibi: principium autem etc., manifestat quod dixerat. Et circa hoc duo facit:	132. Secondly [130], he explains what he has said. About this he does two things:
primo assignat causam unam eius quod dictum est; secundo excludit quandam causam ab aliis opinatam, ibi: qui quidem igitur respiciunt et cetera.	First, he assigns one cause of what has been said, at 132; Secondly, he rejects a cause held by others, at 134.
Circa primum duo facit:	About the first he does two things:
primo assignat causam praedictae transmutationis; secundo assignat causam quare praedicta transmutatio lateat, ibi: sed propterea quod fit et cetera.	First, he assigns the cause of the transmutation just mentioned, at 132; Secondly, he explains why such transmutations escape our notice, at 133.
Dicit ergo primo quod causa et principium transmutationis praedictae hoc est, quod virtus terrae habet suo modo statum et senectutem, sicut corpora animalium et plantarum. In hoc tamen est differentia, quod animalia et plantae patiuntur statum et senectutem, non successive secundum diversas partes, sed simul secundum totum: sed in terra haec transmutatio est secundum partem et partem, propter caliditatem et frigus, crescente una parte in caliditate vel frigore, et alia deminuta, propter motum solis et alias circulationes caelestium corporum. secundum totum in terra, sicut in animalibus et plantis; sed secundum partem et partem.	He says therefore first [130], that the cause and source of the above-mentioned transmutation is that the energy of the earth has its own kind of coming to a stop and old age, just as do bodies of animals and plants. But there is this difference: animals and plants suffer a stopping and old age, not successively with respect to different parts, but all at one time with respect to the whole, while, in the earth, this change is part by part, depending on the influence of heat and cold — for one part increases in heat or coldness, while another decreases, depending on the course of the sun and on other cycles of the heavenly bodies.
Et inde est quod secundum diversum situm in aspectu solis et stellarum, partes terrae recipiunt diversam virtutem; ita quod aliquae partes terrae possunt diu permanere in humiditate et aquositate, secundum aliquod determinatum tempus, quod est eis quasi iuventus vel status; et postmodum siccari, quod est terrae quasi senectus, quae naturaliter propter defectum humorum habet desiccare. Et dum hae partes terrae exsiccantur, alia loca terrae vivificantur, et fiunt aquosa secundum aliquam partem. Quod patet per hoc, quia in vere omnia quasi iuvenescunt per humiditatem; quae in hieme postea senescunt propter nimiam siccitatem. Et in vere etiam nostrae partes terrae sunt in vigore, alibi vero sunt iam desiccata omnia. Et sic patet quod senectus et iuventus non accidunt	Hence, depending on their differing position as to the aspects toward the sun and stars, the parts of the earth receive diverse power. As a result, some parts of the earth can continue being moist and watery for a long time according to a definite period — and this is, as it were, their youth or full state; later, they dry up and exist in what is for the earth old age, which naturally is accompanied by dryness, because of the absence of moisture. While these portions of the earth are drying up, other regions of earth are being vivified and become in part watery. This is indicated by the fact that in the spring of the year all things become, so to speak, young again by moisture; but in winter the same things grow old because of the excessive dryness. Moreover, in spring our part of the earth is alive, while elsewhere everything is already dried up. From this it is plain that old age and youth do not affect the earth as a whole (as animals and plants are affected) but one part at a time.
Sic igitur in aliquibus partibus terrae, desiccatae modo praedicto fontes destruuntur: et ex hoc sequitur quod fluvii primo quidem ex magnis rediguntur in parvos, et tandem totaliter exsiccantur, propter siccitatem fontium ex quibus oriebantur. Et sic in una parte terrae, quae iam senuit, exsiccantur; in alia autem, quae facta est aquosa, proportionaliter de novo fiunt fontes et flumina. Et ita facta transmutatione circa flumina, ut scilicet in una parte terrae deficiant et in alia de novo esse incipiant, transmutatur per consequens mare; et ubi abundaverat primo per excrescentiam fluviorum, siccatis fluviis, recedit mare et remanet arida; ubi vero mare exsiccabatur per aliquam atterrationem causatam ex aliquibus fluxibus supervenientibus terrae, iterum ibidem stagnat, aquae abundantia congregata.	According to this, therefore, in certain areas of the earth, the springs that are dried up in this way cease to function. As a result, rivers that were once large become small, and finally dry up entirely; because the springs from which they originated are dry. Thus, in one part of the earth now grown old, the springs are dry, but in another part that has become watery, a corresponding number of new springs and rivers arise. Hence, because of these changes which affect streams, so that in one portion of the earth they perish and in another portion new ones arise, the sea too is changed as a consequence. Once the rivers dry up, the sea falls back and dry land appears where the sea was once swollen by the overflow of rivers. But where the sea has been dried up by accretions of earth deposited by rivers, it again is under water when a quantity of water has gathered.
Secundo ibi: sed propterea quod fit etc., assignat rationem quare praedictae transmutationes latent. Et dicit quod praedictae transmutationes maris et aridae latent, quia omnis naturalis transmutatio non fit subito, sed successive; et praedictae transmutationes, quae accidunt circa magnas partes terrae, fiunt in temporibus longissimis; et prius fit interitus et corruptio omnium gentium, quam maneat memoria transmutationis talis a sui principio usque in finem. Si enim semper eaedem gentes remanerent in eisdem partibus terrae, posset remanere aliqua memoria rerum etiam antiquissimarum, et transmutationum: sed quando aliqua gens deletur, et supervenit nova in locum eius, non remanet in secunda gente memoria antiquitatum quae fuerunt in prima gente; et multo minus in tertia vel quarta.	133. Secondly [131], he explains why these transmutations escape our notice, and says that these transmutations of sea and dry land escape us, because every natural change takes place not all at once but bit by bit — and the transmutations under discussion, which affect large sectors of the earth occur over long periods of time; and all nations die and pass away before a memory remains of such a change from its beginning to its end. For if the same peoples always remained in the same areas of the earth, some remembrance, even of things most ancient and of transmutations, could remain — but when one people is destroyed and a new one inhabits their land, no memory of the antiquities of the first remains among the second, much less among the third and fourth.
Corruptiones autem gentium quae novissimae sunt, fiunt per praelia, aliae autem fiunt per infirmitates et epidemias, aliae autem per sterilitates; et harum corruptionum quaedam sunt magnae simul, quaedam vero fiunt paulatim; ut etiam transmutationes gentium de loco ad locum lateant, eo quod aliqui a principio, ex eo quod incipit terra fieri sterilis vel infirma, vel propter guerras, relinquunt regionem, alii autem permanent quandiu possunt ibi nutriri; ita quod a primo discessu usque ad ultimum, quandoque est magnum tempus, et non est memoria primi recessus, etiam si homines non moriantur sed transmigrant. Et sicuti est de desertione terrarum, ita etiam est de habitatione earum: quia non est memoria, propter longinquitatem temporis, quando et a quibus gentibus primo inhabitari coeperunt, et quando sunt immutata ex paludosis in siccitatem, ut habitari possint; quia hoc paulatim factum est et in multo tempore. Et ponit exemplum de terra Aegypti, quae paulatim exsiccata est quasi a fluvio; et de quibusdam aliis terris, quae sunt transmutatae et desiccatae ab aquositate, et e converso; et est planum in littera.	Now the disappearances of nations closest to our times are brought on by wars, but some also by diseases and epidemics, and some by sterility: of these destructions some occur all at once on a large scale, and some gradually. Furthermore, the migrations of peoples from place to place go unnoticed, because some forsake a region from the start because the earth is becoming barren or weak, or because of wars; while others remain as long as they can find sustenance there. Hence, the time between the first departure and the last is sometimes long, and there is no memory of the first migration, even if the men do not die, but migrate. And as it is with forsaking lands, so with their settling: because of the length of time, there is no record when and by which races the land first began to be settled and when it was first changed from swamp into dry land and made habitable — this taking place little by little and over long periods of time. And he gives the example of Egypt, whose land was gradually drained dry, as though by the river. He mentions other lands, too, that have been transmuted and drained dry of moisture, and vice versa, as is plain in the text.
Deinde cum dicit: qui quidem igitur respiciunt etc., excludit causam a quibusdam opinatam. Et circa hoc tria facit. Primo excludit causam falsam. Et dicit quod aliqui, respicientes ad aliquid modicum, volunt iudicare de toto caelo: putant enim causam talium transmutationum esse mutationem totius mundi, ac si caelum et mundus de novo sit generatus. Et ex hac causa dicunt quod mare est minoratum, quia a principio coepit desiccari a sole: unde plura loca apparent modo desiccata, quae prius non erant. Sed hoc partim est verum, partim non. Quod enim aliqua loca sint desiccata, quae erant prius aquosa, verum est: licet etiam contrarium verum sit, quia in aliquibus locis invenitur supervenisse mare ubi prius erat arida. Sed hoc est falsum, quod causa huius transmutationis sit mundi generatio. Derisibile enim videtur ponere transmutationem in toto, propter transmutationes in parvis partibus; magnitudo autem terrae quasi nihil est in comparatione ad totum caelum; obtinet enim vicem puncti.	134. Then [132] he dismisses an explanation that some have suggested. About this he does three things: first, he dismisses the false explanation and says that some, by looking at some slight thing, want to make a judgment about the entire heaven: for they think that the cause of such transmutation is that the whole world is changing in the sense that the heaven and the world are being newly formed. They say that the sea gets smaller, because it was beginning to be dried up by the sun from the very beginning: that is why many places formerly moist are now dry. But this is partly true, partly not. For it is true that certain places formerly tilled with water are now dried out; but the opposite is also true, because in some places the sea is found to have invaded areas that were formerly dry land. But it is false that the cause of this change is due to a generation of the earth. For it is ridiculous to postulate transmutations in the whole because of transmutations in small areas. Moreover, the size of the earth is almost as nothing compared with the heaven as a whole, for it takes on the status of a point.
Secundo ibi: sed horum omnium etc., resumit veram causam. Et dicit quod vera causa istarum transmutationum est quod, sicut unus annus dividitur per diversa tempora, scilicet per hiemem et aestatem et consueta, sic et magna aliqua circulatio dividitur secundum statuta tempora, per magnam hiemem, in qua est multus excessus imbrium, et magnam aestatem, in qua est siccitas magna: non autem ita quod simul fiat iste magnus excessus imbrium vel siccitatis secundum totam terram, vel semper secundum easdem partes, sed in diversis partibus. Et ponit exemplum de diluvio facto tempore Deucalionis, in quadam determinata parte Graeciae.	135. Secondly [133], he restates the true cause, and says that the true cause of those transmutations is this: just as a year is divided by different seasons, namely, by winter and summer and the customary seasons, so also a certain great cycle is divided according to established sequences by a great winter, wherein there is an excess of storms, and a great summer, in which there is excessive dryness; but not in the sense that these great excesses of storms and dryness occur at the same time over the entire earth or always over the same regions: they occur in different regions. And he gives the example of the deluge in one definite region of Greece in the time of Deucalion.
Tertio ibi: cum igitur talis factus fuerit etc., assignat ex praedictis causam diuturnitatis fluviorum. Et dicit quod cum in aliqua terra factus fuerit magnus excessus imbrium, ita imbibitur terra humiditate, quod sufficit ad multum tempus ad generationem fluviorum. Quod quidem commune est diversis opinionibus: sive dicatur quod perpetuitas fluviorum est ex magnitudine voraginum continentium multam aquam, ut quidam dicunt, sicut praedictum est; sive dicatur, secundum nostram opinionem superius positam, quod causa perpetuitatis fluviorum est magnitudo et spissitudo et frigiditas altorum locorum, ita quod huiusmodi loca possunt recipere multam aquam, et continere eam, et generare. Sed illa loca in quibus sunt parvae substantiae montium et non multum elevatae in altum, aut sunt quasi spongiosae, ut non possit in eis conservari humiditas, et sunt lapidosae, ut non possint recipere aquam, et sunt argillosae, ut non possint eam generare: in talibus, inquam, locis deficit fluxus fluviorum, quoadusque iterum loca humectentur. Sic ergo oportet putare quod in quibuscumque locis advenerit abundantia imbrium in magna hieme, humiditates locorum erunt magis perpetuae, idest diuturnae. Sed tamen tempore procedente exsiccantur, et quaedam eorum fiunt minus humida, donec iterum revertatur periodus secundum quam fiat excessus imbrium.	136. Thirdly [134], from the foregoing he assigns a cause why rivers last, and says that when excessive storms occur in some region, the earth is saturated with enough moisture to generate rivers for a long time. This is a detail common to various explanations: whether the perpetuity of rivers is explained by large subterranean depths containing much water, as claimed by some, as cited earlier; or whether, according to our own opinion already given, the cause of their perpetuity is the size and thickness and coldness of mountains, by which they can receive and contain vast stores of water as well as generate it. But those places where the substance of the mountains is small and they are not very high, or where they are, so to speak, spongy [porous] so that moisture cannot be preserved in them, and are rocky, so as not to be able to receive water, and are clayey, so as not to be able to generate it, in such places, I say, the flow of rivers diminishes until the region again becomes moist. Therefore, one must believe that in whatever places an abundance of water falls during a great winter, the moisture of such places will be more "perpetual," i.e., long-lasting. Yet, as time goes on, such places dry up and some become less moist until the return again of that period in which there is an excess of rain.
Et sic ultimo concludit quod, quia in toto universo necesse est fieri permutationem; non tamen ita quod generetur et corrumpatur, si totus mundus est perpetuus; necesse est, sicut dictum est, quod non semper eadem loca sint humida per mare vel flumina, aut etiam sicca; sed quae prius fuerunt humida, fiunt sicca, et e converso.	And so he concludes finally that, since change must take place in the whole universe (but not in the sense that the whole comes into being and is destroyed), if the world as a whole is perpetual, then it is necessary, as was said, that the same places be not forever moist, because of the sea or rivers, or dry, either — but places that previously were wet, become dry, and vice versa.
Deinde cum dicit: manifestat autem quod etc., manifestat quod dictum est, per exempla. Et circa hoc tria facit. Primo ponit tria exempla. Quorum primum est de terra Aegypti, quae invenitur demissior mari circumstante: propter quam causam impediti sunt quidam reges ne coniungerent duo maria, videntes per hoc destrui fluxum fluvii.	137. Then [135] he manifests what he has said with examples. About this he does three things: First, he gives three examples, the first of which concerns the land of Egypt, which is found to be below the surrounding sea; for this reason certain of their kings were hindered from linking the two seas, when they saw that this would destroy the flow of the river water.
Secundum exemplum est de Maeotide palude, in qua, propter fluxus fluviorum, semper maior atteratio facta est: ita quod poterat ferre multo minores naves tempore suo, quam ante sexaginta annos.	The second example concerns Lake Maeotis [Sea of Azov], in which the river flow produces so much silt that in his time it could only take boats much smaller than 60 years earlier.
Tertium exemplum est de Bosphoro dividente Europam ab Asia, qui invenitur minoratus et semper tendens in angustum, propter eandem causam.	The third example concerns the Bosphorus, which divides Europe from Asia. This strait is found smaller, and always tending to narrow, for the same reason.
Secundo ibi: manifestum igitur etc., inducit conclusionem principaliter intentam: dicens quod, ex quo tempus non deficit et totum universum est aeternum (quod dicit secundum opinionem suam positam in libro physicorum et de caelo et mundo), sequitur quod neque Tanais neque Nilus, qui sunt maximi fluvii, semper fluxerunt, sed aliquando locus unde fluunt erat siccus: quia opus eorum, scilicet fluxus ipsorum, habet terminum. Et similiter est in aliis fluviis. Et si hoc est de fluviis, oportet quod idem sit de mari, in quod intrant fluvii: et sic secundum diversa tempora permutatur mare et arida.	138. Secondly [136], he draws the conclusion that was chiefly intended and says that since there is no end to time and since the entire universe is eternal (according to his opinion presented in the Physics and in On the Heavens) it follows that neither the Tanais [Don] nor the Nile, which are very large rivers, have always been flowing, but the place whence they flow was once dry: because their "work," i.e., their flow, has a limit. The same is true of other rivers. And if this is true of rivers, it must be true also of the sea into which rivers flow: that is why, at different times, sea and dry land are reversed.
Hoc tamen quod supponit mundum et tempus aeternum, est erroneum et alienum a fide; nec rationes quibus hoc probavit, sunt demonstrationes, ut alibi est ostensum.	However, his supposition that the world and time are eternal is erroneous and opposed to the faith; nor are the arguments used to support these suppositions, demonstrations, as was shown elsewhere.
Tertio ibi: quia quidem igitur, recapitulat quod dixerat: et est planum in littera.	Thirdly [137], he summarizes what he has said, and the text is clear.

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Β
BOOK II

Lecture 1 Opinions of the ancients on the origin of the sea and of its saltiness
Chapter 1
Περὶ δὲ θαλάττης, καὶ τίς ἡ φύσις αὐτῆς, καὶ διὰ τίν' αἰτίαν ἁλμυρὸν τοσοῦτόν ἐστιν ὕδατος πλῆθος, ἔτι δὲ περὶ τῆς ἐξ ἀρχῆς γενέσεως λέγωμεν.	138 Let us explain the nature of the sea and the reason why such a large mass of water is salt and the way in which it originally came to be.
οἱ μὲν οὖν ἀρχαῖοι καὶ διατρίβοντες περὶ τὰς θεολογίας ποιοῦσιν αὐτῆς πηγάς, ἵν' (353b.) αὐτοῖς ὦσιν ἀρχαὶ καὶ ῥίζαι γῆς καὶ θαλάττης τραγικώτερον γὰρ οὕτω καὶ σεμνότερον ὑπέλαβον ἴσως εἶναι τὸ λεγόμενον, ὡς μέγα τι τοῦ παντὸς τοῦτο μόριον ὄν καὶ τὸν λοιπὸν οὐρανὸν ὅλον περὶ τοῦτον συνεστάναι τὸν τόπον καὶ τούτου χάριν ὡς ὄντα τιμιώτατον καὶ ἀρχήν.	139 The old writers who invented theogonies say that the sea has springs, for they want earth and sea to have foundations and roots of their own. Presumably they thought that this view was grander and more impressive as implying that our earth was an important part of the universe. For they believed that the whole world had been built up round our earth and for its sake, and that the earth was the most important and primary part of it.
οἱ δὲ σοφώτεροι τὴν ἀνθρωπίνην σοφίαν ποιοῦσιν αὐτῆς γένεσιν εἶναι γὰρ τὸ πρῶτον ὑγρὸν ἅπαντα τὸν περὶ τὴν γῆν τόπον, ὑπὸ δὲ τοῦ ἡλίου ξηραινόμενον τὸ μὲν διατμίσαν πνεύματα καὶ τροπὰς ἡλίου καὶ σελήνης φασὶ ποιεῖν, τὸ δὲ λειφθὲν θάλατταν εἶναι διὸ καὶ ἐλάττω γίγνεσθαι ξηραινομένην οἴονται, καὶ τέλος ἔσεσθαί ποτε πᾶσαν ξηράν. ἔνιοι δ' αὐτῶν θερμαινομένης φασὶν ὑπὸ τοῦ ἡλίου τῆς γῆς οἷον ἱδρῶτα γίγνεσθαι διὸ καὶ ἁλμυρὰν εἶναι καὶ γὰρ ὁ ἱδρὼς ἁλμυρός. οἱ δὲ τῆς ἁλμυρότητος αἰτίαν τὴν γῆν εἶναί φασιν καθάπερ γὰρ τὸ διὰ τῆς τέφρας ἠθούμενον ἁλμυρὸν γίγνεται, τὸν αὐτὸν τρόπον καὶ ταύτην ἁλμυρὰν εἶναι μειχθείσης αὐτῇ τοιαύτης γῆς.	140 Others, wiser in human knowledge, give an account of its origin. At first, they say, the earth was surrounded by moisture. Then the sun began to dry it up, part of it evaporated and is the cause of winds and the turnings back of the sun and the moon, while the remainder forms the sea. So the sea is being dried up and is growing less, and will end by being some day entirely dried up. Others say that the sea is a kind of sweat exuded by the earth when the sun heats it, and that this explains its saltness: for all sweat is salt. Others say that the saltness is due to the earth. Just as water strained through ashes becomes salt, so the sea owes its saltness to the admixture of earth with similar properties.
ὅτι μὲν οὖν πηγὰς τῆς θαλάττης ἀδύνατον εἶναι, διὰ τῶν ὑπαρχόντων ἤδη θεωρεῖν δεῖ. τῶν γὰρ περὶ τὴν γῆν ὑδάτων τὰ μὲν ῥυτὰ τυγχάνει ὄντα τὰ δὲ στάσιμα. τὰ μὲν οὖν ῥυτὰ πάντα πηγαῖα περὶ δὲ τῶν πηγῶν εἰρήκαμεν πρότερον ὅτι δεῖ νοεῖν οὐχ ὥσπερ ἐξ ἀγγείου ταμιευόμενον τὴν ἀρχὴν εἶναι πηγήν, ἀλλ' εἰς ἓν ἀεὶ γιγνόμενον καὶ συρρέον ἀπαντᾶν πρώτην. τῶν δὲ στασίμων τὰ μὲν συλλογιμαῖα καὶ ὑποστάσεις, οἷον τὰ τελματιαῖα καὶ ὅσα λιμνώδη, πλήθει καὶ ὀλιγότητι διαφέροντα, τὰ δὲ πηγαῖα. ταῦτα δὲ πάντα χειρόκμητα, λέγω δ' οἷον τὰ φρεατιαῖα καλούμενα πάντων γὰρ ἀνωτέρω δεῖ τὴν πηγὴν εἶναι τῆς ῥύσεως. διὸ τὰ μὲν αὐτόματα ῥεῖ τὰ κρηναῖα καὶ ποτάμια, ταῦτα δὲ τέχνης προσδεῖται τῆς ἐργασομένης. αἱ μὲν οὖν διαφοραὶ τοσαῦται καὶ τοιαῦται τῶν ὑδάτων εἰσίν τούτων δ' οὕτω διωρισμένων ἀδύνατον πηγὰς εἶναι τῆς θαλάττης ἐν οὐδετέρῳ γὰρ τούτων οἷόν τ' εἶναι τῶν γενῶν αὐτήν οὔτε γὰρ ἀπόρρυτός ἐστιν οὔτε χειροποίητος, τὰ δὲ πηγαῖα πάντα τούτων θάτερον πέπονθεν αὐτόματον δὲ στάσιμον τοσοῦτον πλῆθος οὐδὲν ὁρῶμεν πηγαῖον γιγνόμενον.	141 We must now consider the facts which prove that the sea cannot possibly have springs. The waters we find on the earth either flow or are stationary. All flowing water has springs. (By a spring, as we have explained above, we must not understand a source from which waters are ladled as it were from a vessel, but a first point at which the water which is continually forming and percolating gathers.) Stationary water is either that which has collected and has been left standing, marshy pools, for instance, and lakes, which differ merely in size, or else it comes from springs. In this case it is always artificial, I mean as in the case of wells, otherwise the spring would have to be above the outlet. Hence the water from fountains and rivers flows of itself, whereas wells need to be worked artificially. All the waters that exist belong to one or other of these classes. On the basis of this division we can see that the sea cannot have springs. For it falls under neither of the two classes; it does not flow and it is not artificial; whereas all water from springs must belong to one or other of them. Natural standing water from springs is never found on such a large scale.
ἔτι δ' ἐπεὶ πλείους εἰσὶ (354a.) θάλατται πρὸς ἀλλήλας οὐ συμμειγνύουσαι κατ' οὐδένα τόπον, ὧν ἡ μὲν ἐρυθρὰ φαίνεται κατὰ μικρὸν κοινωνοῦσα πρὸς τὴν ἔξω στηλῶν θάλατταν, ἡ δ' Ὑρκανία καὶ Κασπία κεχωρισμέναι τε ταύτης καὶ περιοικούμεναι κύκλῳ, ὥστ' οὐκ ἂν ἐλάνθανον αἱ πηγαί, εἰ κατά τινα τόπον αὐτῶν ἦσαν.	142 Again, there are several seas that have no communication with one another at all. The Red Sea, for instance, communicates but slightly with the ocean outside the straits, and the Hyrcanian and Caspian seas are distinct from this ocean and people dwell all round them. Hence, if these seas had had any springs anywhere they must have been discovered.
ῥέουσα δ' ἡ θάλαττα φαίνεται κατά τε τὰς στενότητας, εἴ που διὰ τὴν περιέχουσαν γῆν εἰς μικρὸν ἐκ μεγάλου συνάγεται πελάγους, διὰ τὸ ταλαντεύεσθαι δεῦρο κἀκεῖσε πολλάκις. τοῦτο δ' ἐν μὲν πολλῷ πλήθει θαλάττης ἄδηλον ᾗ δὲ διὰ τὴν στενότητα τῆς γῆς ὀλίγον ἐπέχει τόπον, ἀναγκαῖον τὴν ἐν τῷ πελάγει μικρὰν ταλάντωσιν ἐκεῖ φαίνεσθαι μεγάλην. ἡ δ' ἐντὸς Ἡρακλείων στηλῶν ἅπασα κατὰ τὴν τῆς γῆς κοιλότητα ῥεῖ, καὶ τῶν ποταμῶν τὸ πλῆθος ἡ μὲν γὰρ Μαιῶτις εἰς τὸν Πόντον ῥεῖ, οὗτος δ' εἰς τὸν Αἰγαῖον. τὰ δ' ἤδη τούτων ἔξω πελάγη ἧττον ποιεῖ τοῦτ' ἐπιδήλως. ἐκείνοις δὲ διά τε τὸ τῶν ποταμῶν πλῆθος συμβαίνει τοῦτο (πλείους γὰρ εἰς τὸν Εὔξεινον ῥέουσιν ποταμοὶ καὶ τὴν Μαιῶτιν ἢ τὴν πολλαπλασίαν χώραν αὐτῆς) καὶ διὰ τὴν βραχύτητα τοῦ βάθους ἀεὶ γὰρ ἔτι βαθυτέρα φαίνεται οὖσα ἡ θάλαττα, καὶ τῆς μὲν Μαιώτιδος ὁ Πόντος, τούτου δ' ὁ Αἰγαῖος, τοῦ δ' Αἰγαίου ὁ Σικελικός ὁ δὲ Σαρδονικὸς καὶ Τυρρηνικὸς βαθύτατοι πάντων. τὰ δ' ἔξω στηλῶν βραχέα μὲν διὰ τὸν πηλόν, ἄπνοα δ' ἐστὶν ὡς ἐν κοίλῳ τῆς θαλάττης οὔσης. ὥσπερ οὖν καὶ κατὰ μέρος ἐκ τῶν ὑψηλῶν οἱ ποταμοὶ φαίνονται ῥέοντες, οὕτω καὶ τῆς ὅλης γῆς ἐκ τῶν ὑψηλοτέρων τῶν πρὸς ἄρκτον τὸ ῥεῦμα γίγνεται τὸ πλεῖστον ὥστε τὰ μὲν διὰ τὴν ἔκχυσιν οὐ βαθέα, τὰ δ' ἔξω πελάγη βαθέα μᾶλλον.	143 It is true that in straits, where the land on either side contracts an open sea into a small space, the sea appears to flow. But this is because it is swinging to and fro. In the open sea this motion is not observed, but where the land narrows and contracts the sea the motion that was imperceptible in the open necessarily strikes the attention. The whole of the Mediterranean does actually flow. The direction of this flow is determined by the depth of the basins and by the number of rivers. Maeotis flows into Pontus and Pontus into the Aegean. After that the flow of the remaining seas is not so easy to observe. The current of Maeotis and Pontus is due to the number of rivers (more rivers flow into the Euxine and Maeotis than into the whole Mediterranean with its much larger basin), and to their own shallowness. For we find the sea getting deeper and deeper. Pontus is deeper than Maeotis, the Aegean than Pontus, the Sicilian sea than the Aegean; the Sardinian and Tyrrhenic being the deepest of all. (Outside the pillars of Heracles the sea is shallow owing to the mud, but calm, for it lies in a hollow.) We see, then, that just as single rivers flow from mountains, so it is with the earth as a whole: the greatest volume of water flows from the higher regions in the north. Their alluvium makes the northern seas shallow, while the outer seas are deeper.
περὶ δὲ τοῦ τὰ πρὸς ἄρκτον εἶναι τῆς γῆς ὑψηλὰ σημεῖόν τι καὶ τὸ πολλοὺς πεισθῆναι τῶν ἀρχαίων μετεωρολόγων τὸν ἥλιον μὴ φέρεσθαι ὑπὸ γῆν ἀλλὰ περὶ τὴν γῆν καὶ τὸν τόπον τοῦτον, ἀφανίζεσθαι δὲ καὶ ποιεῖν νύκτα διὰ τὸ ὑψηλὴν εἶναι πρὸς ἄρκτον τὴν γῆν.	144 Some further evidence of the height of the northern regions of the earth is afforded by the view of many of the ancient meteorologists. They believed that the sun did not pass below the earth, but round its northern part, and that it was the height of this which obscured the sun and caused night.
ὅτι μὲν οὖν οὔτε πηγὰς οἷόν τ' εἶναι τῆς θαλάττης, καὶ διὰ τίν' αἰτίαν οὕτως φαίνεται ῥέουσα, τοιαῦτα καὶ τοσαῦθ' ἡμῖν εἰρήσθω.	So much to prove that there cannot be sources of the sea and to explain its observed flow.

Postquam philosophus determinavit de his quae generantur in alto, sive ab exhalatione sicca sive a vapore humido, adiungens etiam de generatione fluviorum, propter similitudinem ad generationem pluviarum, nunc incipit determinare de his quae fiunt in parte inferiori ab exhalatione sicca. Et dividitur in partes duas:	139. After determining concerning things generated on high, from either a dry evaporation or a moist vapor, and after adding a discussion about the generation of rivers on account of its similarity to the generation of rains, the Philosopher now begins to determine concerning things that come to be in the lower region from a dry exhalation. And it is divided into two parts:
in prima determinat de quibusdam principalibus passionibus; in secunda de quibusdam consequentibus, et hoc in tertio libro, ibi: de residuis autem et cetera.	In the first he determines about certain principal passions, at 140; In the second about certain things which accompany them ().
Prima dividitur in duas:	The first is divided into two parts:
in prima determinat de mari, cuius salsedo ex siccitate causatur; in secunda determinat de ventis et his quae ex eis causantur, ibi: de spiritibus autem dicamus et cetera.	In the first he determines about the sea, whose saltiness is caused by dryness, at 140; In the second about winds and the things caused by them (L. 7).
Satis autem apparet conveniens ordo quem philosophus observat. Nam post ea quae in suprema parte aeris generantur ab exhalatione sicca, quae stellae cadentes, cometae, lacteus circulus, et similia sunt, in secundo loco determinavit de his quae in inferiori loco generantur ab exhalatione humida, scilicet de pluviis et huiusmodi; et quia eodem modo habent flumina causam generationis in terra, sicut pluviae in aere, post pluvias de fluminibus determinavit; post quae determinat de mari, in quod omnia flumina decurrunt.	140. The order which the Philosopher observes seems quite suitable. For after determining about things generated in the upper region of air from dry exhalation, namely, falling stars, comets, the milky circle and like things, he secondly determined about things generated in the lower region from moist exhalation, namely, rains and so on: and because rivers have a cause of their generation in the earth in the same way as rain in the air, after rains he determined about rivers. After this he determines about the sea, into which all rivers flow.
Circa hoc ergo primo manifestat de quo est intentio. Et dicit quod dicendum est de mari: quae scilicet sit natura ipsius, utrum sit naturalis locus aquae, vel accidentaliter ibi aqua congregetur; et propter quam causam tanta multitudo aquae est salsa; et de prima generatione maris, utrum scilicet habeat principium suae generationis, et quomodo.	Concerning this, therefore, he first declares his intention [138] and says that we must speak now of the sea: namely, as to what its nature is, whether it is the natural place of water or is it by accident that water is gathered there; as to what is the cause of such an abundance of water's being salty; and of the primal generation of the sea, i.e., does it have a source of its generation and how?
Secundo ibi: antiqui quidem igitur etc., exequitur propositum. Et circa hoc duo facit:	143. Secondly [139], he pursues his proposition, about which he does two things:
primo ponit opiniones aliorum de mari; secundo inquirit veritatem, ibi: quod quidem igitur fontes et cetera.	First, he presents the opinions of others about the sea, at 141; Secondly, he investigates the truth, at 143.
Circa primum duo facit:	Concerning the first he does two things:
primo ponit opiniones antiquorum theologorum; secundo naturalium, ibi: qui autem sapientiores et cetera.	First, he gives the opinions of ancient theologizers, at 141; Secondly, of the philosophers of nature, at 142.
Circa primum sciendum est quod ante tempora philosophorum, fuerunt quidam qui vocabantur poetae theologi, sicut Orpheus, Hesiodus et Homerus: quia sub tegumento quarundam fabularum, divina hominibus tradiderunt. De his ergo dicit quod posuerunt quod mare habeat fontes proprios ex quibus causatur. Et hoc posuerunt ut terrae et mari non ponerent extranea principia sed propria: putaverunt enim quod terra et aqua sint reverendissima, quasi haec sit magna pars totius universi; et dicebant totum caelum esse propter terram et aquam, et ideo circumdari terram et aquam ab aliis corporibus et ab ipso, ac si haec pars esset honoratissima, et primum principium inter omnia corpora mundi.	Regarding the first [139] one must know that before the times of the philosophers there were men called theologizing poets (such as Orpheus, Hesiod and Homer), because under the guise of fables they declared divine things to men. Concerning them, therefore, he says that they posited the sea to have springs of its own from which it is caused. They postulated this so as to avoid attributing to earth and sea extraneous principles not their own: for they believed the earth and sea to be most worthy of reverence, as though they were a great part of the whole universe; and they said that the whole heaven exists for the sake of earth and water and that that is why earth and water are surrounded by other bodies and by the heaven itself, as though this part were most worthy of honor and the first principle among all the bodies of the universe.
Deinde cum dicit: qui autem sapientiores etc., ponit opiniones philosophorum naturalium de mari. Et ponit tres opiniones. Quarum prima est de generatione maris. Et dicit quod illi qui fuerunt sapientiores praedictis poetis sapientia humana (quod dicit quia isti naturales non tractaverunt de divinis, ut illi, sed de naturalibus; quae est sapientia proprie humana, idest conformis humano intellectui): isti ergo dixerunt quod mare habet generationem. Quia a principio totus locus qui est circa terram, erat humidus et plenus aqua, sed est desiccatus a sole per evaporationem humidi; et illud quidem quod evaporavit, secundum eos, causavit aerem et ventos (et ex hoc dicunt causari motum solis et lunae et stellarum); illud autem quod est relictum nondum exsiccatum, est mare. Unde putant quod per continuam exsiccationem semper minoretur, et tandem aliquando totum exsiccabitur, et mare iam non erit. Haec dicitur fuisse opinio Anaxagorae et Diogenis.	142. Then [140] he presents the opinions of the natural philosophers concerning the sea and gives three opinions. The first concerns the generation of the sea and he says that those wiser in "human wisdom" than the aforesaid poets (he says this because the naturalists dealt not with divine things, as did they, but with natural things, which is proper to human wisdom, i.e., conformed to the human intellect), said that the sea has generation. This is because from the beginning the entire region surrounding the earth was wet and full of water, but became dried out by the sun's evaporating the moisture: what evaporated, according to them, caused air and winds (and from this, they say, are caused the movement of the sun and moon and stars); what was left not yet dried up, is the sea. Hence they believe that by a continuous drying-up it is always shrinking, so that finally it will all be dried up and the sea exist no more. This is said to have been the opinion of Anaxagoras and Diogenes.
Secunda opinio est de salsedine maris. Empedocles enim dixit quod terra, calefacta a sole, emittit quendam sudorem, quem credidit esse aquam maris. Et propterea dicit quod mare est salsum, quia etiam sudor animalium invenitur salsus.	The second opinion is about the salt of the sea. For Empedocles said that the earth, warmed by the sun, exudes a certain sweat which, he believed, is the water of the sea. For this reason, so he says, the sea is salty, since the sweat of animals also is found to be salty.
Tertia opinio est Anaxagorae etiam de salsedine maris. Qui dixit quod terra per quam transit aqua, vel quae admiscetur aquae, est causa salsedinis maris: sicut enim illud quod colatur per cinerem, fit salsum, sic et aqua maris per admixtionem terrae fit salsa.	The third opinion, that of Anaxagoras, also concerns the salt of the sea. He said that the earth through which the water passes, or which is mingled with the water, causes the salt of the sea: for just as something strained through ashes becomes salty, so the water of the sea becomes salty by an admixture of earth.
Deinde cum dicit: quod quidem igitur fontes etc., inquirit veritatem circa praedictas opiniones:	143. Then [141] he searches for the truth regarding these opinions.
et primo circa opinionem poetarum theologizantium; secundo circa opiniones philosophorum naturalium, ibi: de generatione autem ipsius, si factum est et cetera.	First, about the opinion of the theologizing poets at 143; Secondly, about the opinions of the philosophers of nature (L. 2).
Circa primum duo facit:	About the first he does two things:
primo ostendit quod mare non habet fontes, ut illi dixerunt; secundo removet quoddam quod videtur suae rationi contrarium, ibi: fluens autem mare videtur et cetera.	First, he shows that the sea has no springs, as they said, at 143; Secondly, he gives an answer to something seemingly contrary to his own argument, at 145.
Circa primum ponit duas rationes. Quarum prima est, quod aquarum quae sunt circa terram, quaedam sunt fluxibiles, quaedam stationariae. De his quae fluunt, manifestum est quod omnes derivantur ex fontibus. Quod non oportet sic intelligere, quod fontium sit aliquod principium quasi vas continens multitudinem aquae, ex quo flumina deriventur: sed oportet intelligere, ut prius dictum est, quod ex multis partibus, in quibus paulatim generatur, aqua ad unum concurrit, et confluendo primum sibi occurrit ut in tanta multitudine sit. Sed aquarum stationariarum quaedam sunt collectae et sustentatae ab aliquo impediente fluxum earum, vel per artem vel per naturam; quae dicuntur paludosae vel stagnales. Differunt autem haec multitudine et paucitate: nam si fuerint multae aquae sic collectae, dicuntur stagna; si autem paucae, paludes. Quaedam autem aquae stationariae sunt fontanae, idest in ipso suo fonte stant: et omnes istae sunt manufactae, sicut illae quae dicuntur puteales. Omnium enim harum aquarum sic per artem stantium, oportet esse aliquem fontem, qui esset principium fluxus, nisi impediretur per artem. Unde patet quod omnes aquae fontales et fluviales sponte fluunt secundum impetum naturae, vel indigent operatione artis ad hoc quod stent.	Concerning the first [141] he presents two arguments. The first is that among the waters surrounding the earth, some can flow and some are stationary. Of those that flow it is plain that all are derived from springs. But this does not mean that the springs have as their source, as it were, a container holding a vast store of water, from which rivers are derived: it means, as already stated, that from the many places where it is formed little by little [drop by drop], the water comes together, and that it is by such confluence that it for the first time comes to be in so great a quantity. But with regard to stationary waters, some are collected and held in one place by something artificial or natural that obstructs the flow, and are called marshes or ponds. These differ by reason of largeness or smallness: for if a large store of water has been thus collected, it is called a pond; if a little, a marsh. Now, some stationary waters are "fountainous," i.e., they subsist in their own source; all such are man-made, for example, wells. For all such waters thus stationary through art must have a spring, which would make them flow unless they were artificially prevented. Hence it is plain that all water from fountains and rivers flows of itself according to the inclination of nature, or, if it is to be stationary, must be made so artificially.
Quibus determinatis, patet quod aqua maris non est de fontibus, quia in nullo duorum dictorum generum continetur: quia nec fluit, ut fluvialis, nec potest dici quod sit manufacta, ut putealis. Omnes autem aquae quae sunt ex fontibus, vel fluunt, vel stant per artem: nisi forte aliquae sint parvae aquae quae sponte stent non per artem, sicut contingit cum aqua fluens invenit aliquam concavitatem aut aliquod obstaculum. Sed hoc non potest esse in magna quantitate: quia dum multiplicatur aqua fluens, oportet quod vel supergrediatur obstaculum et iterum fluat, vel submergatur in terra, sicut in multis locis accidit, ut supra dictum est. Unde non potest dici quod tanta aqua sicut aqua maris, possit spontanee stare, si sit ex fontibus. Relinquitur ergo quod mare non habeat fontes.	In the light of the foregoing it is plain that the water of the sea does not come from springs, because it falls within neither of the groups mentioned: it does not flow, as river water does, and we cannot say that it is man-made, as a well is. But all waters that come from springs either flow or are stationary by art — unless you include small bodies of water that stand of themselves and not artificially, as when flowing water finds its way into a hollow or meets an obstacle. But such water cannot exist in large amounts: because when the flow water increases, it must either run over the obstacle and start to flow again, or be submerged within the earth, as, we have said, happens in many places. Hence it cannot be said that such a quantity of water as the water of the sea could be standing of itself, if it arose from springs. The conclusion, therefore, is that the sea does not have springs.
Secundam rationem ponit ibi: adhuc autem quoniam plura sunt et cetera. Et dicit quod multa maria sunt quae in nullo loco adinvicem commiscentur. Nam mare rubrum coniungitur quidem secundum modicum ad mare Oceanum, quod est extra columnas Herculis; a quo mari omnino separata sunt mare Hyrcanum et Caspium (quod est mare Ponticum); et habitantur undique per circuitum, ita quod non laterent fontes illius maris, si illud mare fontes haberet. Non ergo verum est quod maris sint aliqui fontes.	144. He gives the second argument [142] and says that there are many seas that have no communication with any other. For the Red Sea joins but slightly with the Ocean Sea beyond the columns of Hercules: from which sea the Hyrcanian and Caspian (which is the sea of Pontus) are far removed. If they had springs, the people who live along all the sides of the sea would not have failed to discover them. It is therefore not true that springs of the sea exist.
Deinde cum dicit: fluens autem mare videtur etc., quia in quibusdam maribus apparet communis fluxus, ne credatur mare esse fluxibile tanquam ex fontibus procedens, cuius contrarium in prima ratione supposuerat, assignat causam fluxus qui videtur in mari. Et circa hoc tria facit:	145. Then [143] because a common flow is apparent in some seas, lest it be supposed that the sea can flow, as if proceeding from springs, the contrary of which he had supposed in the first argument, he assigns the cause of the flow seen in the sea. About this he does three things:
primo ostendit quare aliquod mare fluat; secundo manifestat quoddam quod supponit, per signum, ibi: de eo autem etc.; tertio recapitulat, ibi: quod quidem igitur et cetera.	First, he shows why some sea flows, at 145; Secondly, he manifests what he supposed with a sign, at 146; Thirdly, he summarizes at end of 146.
Assignat autem fluxus maris tres causas. Quarum prima est, quod mare fluit propter eius angustiam, ubi ex magno pelago restringitur in modicum spatium, propter hoc quod coarctatur ab adiacente terra. Aqua autem maris saepe movetur huc et illuc, et maxime secundum consequentiam ad motum lunae, quae secundum naturam propriam habet commovere humidum: haec autem aquae commotio in magno mari et amplo est immanifesta; sed ubi obtinent parvum locum propter angustiam terrae, magis apparet. \	Now he assigns three causes of the sea's flowing [143]. The first is that the sea flows because of its narrowness, where, from being a vast flood, it is confined into a small place because of being narrowed by adjacent land. Now the water of the sea is often moved back and forth, especially as a consequence of the movement of the moon, whose proper nature it is to agitate the moist: but this commotion of water in a large open sea goes unnoticed, but where it occurs in an area rendered small by the narrowness of the land it becomes more noticeable.
Secunda causa est, quod illud mare quod continetur infra Heracleas columnas, et non continuatur alicui, sicut de mari Pontico iam dictum est: istud, inquam, fluit propter multitudinem fluviorum. Et propter eandem causam unum mare decurrit in aliud: nam Maeotis fluit in mare Ponticum, Ponticum fluit in Aegeum. In aliis autem maribus minus hoc videtur: sed in praedictis maribus hoc accidit propter multitudinem fluviorum, quia in praedicta maria multa flumina intrant.	The second cause is that the sea which is contained within the columns of Hercules and does not communicate with any other sea (as was already said of the Sea of Pontus), that sea, I say, flows on account of the large number of rivers. And, for the same reason, one sea flows into another: for Maeotis flows into the Sea of Pontus and the Pontus into the Aegean. In other seas this is not so evident; but in the ones mentioned this happens on account of the number of rivers, for many rivers flow into them.
Tertia ratio fluxus est propter hoc quod mare occupat multum de terra secundum proportionem quantitatis aquae, et unum est minus profundum quam aliud: illud autem quod est minus profundum, semper decurrit ad profundius. Unde illud mare semper videtur profundius, ad quod aliud decurrit, sicut Ponticum est profundius Maeotide, et Pontico mare Aegeum, et Aegeo Siculum; Sardicum autem et Tyrrhenum sunt profundissima. Sed mare quod est extra columnas, non est profundum: quod apparet ex luto apparente in aqua quae fluit ex ipso; et huius signum est quod sunt sine vento, ac si existant in aliqua concavitate. Sicut igitur particulariter fluvii videntur fluentes ex altioribus locis ad demissiora, sic in mari fluxus fit ex altioribus locis terrae, quae sunt ad Septentrionem: ut sic maria Septentrionalia, quae emittunt aquam, non sint ita profunda sicut maria meridionalia, quae recipiunt.	The third reason for the flow is that a sea covers a great deal of earth, in keeping with the quantity of the water, and one sea is not as deep as another; but the one that is not so deep always flows to the deeper one. Hence that sea to which another flows is always seen to be deeper: as, for example, the Pontus is deeper than Maeotis, the Aegean than the Pontus, and the sea of Sicily deeper than the Aegean; but the..Sofian and the Etruscan are the deepest of all. The sea beyond the Columns, however, is not deep, as is evident from the mud in the water flowing out of it. An indication of this is that it is calm, as though it were in a hollow. Therefore, just as individual rivers are seen flowing from higher to lower places, so in the sea, the flow is from the loftier places of the earth, which are in the north: consequently, the northern seas, from which water flows, are not as deep as those in the south which receive it.
Deinde cum dicit: de eo autem etc., manifestat per signum quoddam quod dixerat, scilicet quod terra ex parte Septentrionis sit altior. Et huius signum accipit ex hoc quod quidam antiquorum crediderunt quod sol non iret sub terra, sed solum circa terram, et dispareret de nocte propter altitudinem Septentrionalis partis occultantis. Deinde cum dicit: quod quidem igitur etc., recapitulat quod dixerat: et est planum in littera.	146. Then [144] through a certain sign he manifests what he had said, namely, that the earth is higher toward the north. He takes as an indication of this the fact that some of the ancients believed that the sun did not go below the earth but only around it and that it became invisible at night because the northern heights obscured it. — Then [145] he summarizes what he had said — and it is plain in the text.

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Lecture 2
The sea is shown to be the natural place of all water

Chapter 2
(354b.) περὶ δὲ τῆς γενέσεως αὐτῆς, εἰ γέγονε, καὶ τοῦ χυμοῦ, τίς ἡ αἰτία τῆς ἁλμυρότητος καὶ πικρότητος, λεκτέον.	146 We must now discuss the origin of the sea, if it has an origin, and the cause of its salt and bitter taste.
ἡ μὲν οὖν αἰτία ἡ ποιήσασα τοὺς πρότερον οἴεσθαι τὴν θάλατταν ἀρχὴν εἶναι καὶ σῶμα τοῦ παντὸς ὕδατος ἥδ' ἐστίν δόξειε γὰρ ἂν εὔλογον εἶναι, καθάπερ καὶ τῶν ἄλλων στοιχείων ἐστὶν ἠθροισμένος ὄγκος καὶ ἀρχὴ διὰ τὸ πλῆθος, ὅθεν μεταβάλλει τε μεριζόμενον καὶ μείγνυται τοῖς ἄλλοις—οἷον πυρὸς μὲν ἐν τοῖς ἄνω τόποις, ἀέρος δὲ πλῆθος τὸ μετὰ τὸν τοῦ πυρὸς τόπον, γῆς δὲ σῶμα περὶ ὃ ταῦτα πάντα κεῖται φανερῶς ὥστε δῆλον ὅτι κατὰ τὸν αὐτὸν λόγον καὶ περὶ ὕδατος ἀνάγκη ζητεῖν. τοιοῦτον δ' οὐδὲν ἄλλο φαίνεται σῶμα κείμενον ἀθρόον, ὥσπερ καὶ τῶν ἄλλων στοιχείων, πλὴν τὸ τῆς θαλάττης μέγεθος τὸ γὰρ τῶν ποταμῶν οὔτ' ἀθρόον οὔτε στάσιμον, ἀλλ' ὡς γιγνόμενον ἀεὶ φαίνεται καθ' ἡμέραν.	147 What made earlier writers consider the sea to be the original and main body of water is this. It seems reasonable to suppose that to be the case on the analogy of the other elements. Each of them has a main bulk which by reason of its mass is the origin of that element, and any parts which change and mix with the other elements come from it. Thus the main body of fire is in the upper region; that of air occupies the place next inside the region of fire; while the mass of the earth is that round which the rest of the elements are seen to lie. So we must clearly look for something analogous in the case of water. But here we can find no such single mass, as in the case of the other elements, except the sea. River water is not a unity, nor is it stable, but is seen to be in a continuous process of becoming from day to day. It was this difficulty which made people regard the sea as the origin and source of moisture and of all water. And so we find it maintained that rivers not only flow into the sea but originate from it, the salt water becoming sweet by filtration.
ἐκ ταύτης δὴ τῆς ἀπορίας καὶ ἀρχὴ τῶν ὑγρῶν ἔδοξεν εἶναι καὶ τοῦ παντὸς ὕδατος ἡ θάλαττα.	148 But this view involves another difficulty. If this body of water is the origin and source of all water, why is it salt and not sweet?
διὸ καὶ τοὺς ποταμοὺς οὐ μόνον εἰς ταύτην ἀλλὰ καὶ ἐκ ταύτης φασί τινες ῥεῖν διηθούμενον γὰρ γίγνεσθαι τὸ ἁλμυρὸν πότιμον. ἀντίκειται δὲ ἑτέρα πρὸς ταύτην τὴν δόξαν ἀπορία, τί δή ποτ' οὐκ ἔστιν τὸ συνεστὸς ὕδωρ τοῦτο πότιμον, εἴπερ ἀρχὴ τοῦ παντὸς ὕδατος, ἀλλ' ἁλμυρόν. τὸ δ' αἴτιον ἅμα ταύτης τε τῆς ἀπορίας λύσις ἔσται, καὶ περὶ θαλάττης τὴν πρώτην λαβεῖν ὑπόληψιν ἀναγκαῖον ὀρθῶς. τοῦ γὰρ ὕδατος περὶ τὴν γῆν περιτεταμένου, καθάπερ περὶ τοῦτο ἡ τοῦ ἀέρος σφαῖρα καὶ περὶ ταύτην ἡ λεγομένη πυρός (τοῦτο γάρ ἐστι πάντων ἔσχατον, εἴθ' ὡς οἱ πλεῖστοι λέγουσιν εἴθ' ὡς ἡμεῖς), φερομένου δὲ τοῦ ἡλίου τοῦτον τὸν τρόπον, καὶ διὰ ταῦτα τῆς μεταβολῆς καὶ γενέσεώς τε καὶ φθορᾶς οὔσης, τὸ μὲν λεπτότατον καὶ γλυκύτατον ἀνάγεται καθ' ἑκάστην ἡμέραν καὶ φέρεται διακρινόμενον καὶ ἀτμίζον εἰς τὸν ἄνω τόπον, ἐκεῖ δὲ πάλιν συστὰν διὰ τὴν ψύξιν καταφέρεται πάλιν πρὸς τὴν γῆν.	149 The reason for this, besides answering this question, will ensure our having a right first conception of the nature of the sea. The earth is surrounded by water, just as that is by the sphere of air, and that again by the sphere called that of fire (which is the outermost both on the common view and on ours). Now the sun, moving as it does, sets up processes of change and becoming and decay, and by its agency the finest and sweetest water is every day carried up and is dissolved into vapour and rises to the upper region, where it is condensed again by the cold and so returns to the earth. This, as we have said before, is the regular course of nature.
καὶ τοῦτ' ἀεὶ βούλεται ποιεῖν ἡ φύσις οὕτως, καθάπερ εἴρηται πρότερον. διὸ καὶ γελοῖοι πάντες ὅσοι τῶν πρότερον ὑπέλαβον τὸν ἥλιον τρέφεσθαι τῷ ὑγρῷ καὶ διὰ τοῦτ' ἔνιοί γέ (355a.) φασιν καὶ ποιεῖσθαι τὰς τροπὰς αὐτόν οὐ γὰρ αἰεὶ τοὺς αὐτοὺς δύνασθαι τόπους παρασκευάζειν αὐτῷ τὴν τροφήν ἀναγκαῖον δ' εἶναι τοῦτο συμβαίνειν περὶ αὐτὸν ἢ φθείρεσθαι καὶ γὰρ τὸ φανερὸν πῦρ, ἕως ἂν ἔχῃ τροφήν, μέχρι τούτου ζῆν, τὸ δ' ὑγρὸν τῷ πυρὶ τροφὴν εἶναι μόνον,	150 Hence all my predecessors who supposed that the sun was nourished by moisture are absurdly mistaken. Some go on to say that the solstices are due to this, the reason being that the same places cannot always supply the sun with nourishment and that without it he must perish. For the fire we are familiar with lives as long as it is fed, and the only food for fire is moisture.
—ὥσπερ ἀφικνούμενον μέχρι πρὸς τὸν ἥλιον τὸ ἀναγόμενον τοῦ ὑγροῦ,	151 As if the moisture that is raised could reach the sun!
ἢ τὴν ἄνοδον τοιαύτην οὖσαν οἵανπερ τῇ γιγνομένῃ φλογί, δι' ἧς τὸ εἰκὸς λαβόντες οὕτω καὶ περὶ τοῦ ἡλίου ὑπέλαβον. τὸ δ' οὐκ ἔστιν ὅμοιον ἡ μὲν γὰρ φλὸξ διὰ συνεχοῦς ὑγροῦ καὶ ξηροῦ μεταβαλλόντων γίγνεται καὶ οὐ τρέφεται (οὐ γὰρ ἡ αὐτὴ οὖσα διαμένει οὐδένα χρόνον ὡς εἰπεῖν), περὶ δὲ τὸν ἥλιον ἀδύνατον τοῦτο συμβαίνειν, ἐπεὶ τρεφομένου γε τὸν αὐτὸν τρόπον, ὥσπερ ἐκεῖνοί φασιν, δῆλον ὅτι καὶ ὁ ἥλιος οὐ μόνον καθάπερ Ἡράκλειτός φησιν, νέος ἐφ' ἡμέρῃ ἐστίν, ἀλλ' ἀεὶ νέος συνεχῶς.	152 or this ascent were really like that performed by flame as it comes into being, and to which they supposed the case of the sun to be analogous! Really there is no similarity. A flame is a process of becoming, involving a constant interchange of moist and dry. It cannot be said to be nourished since it scarcely persists as one and the same for a moment. This cannot be true of the sun; for if it were nourished like that, as they say it is, we should obviously not only have a new sun every day, as Heraclitus says, but a new sun every moment.
ἔτι δ' ἡ ὑπὸ τοῦ ἡλίου ἀναγωγὴ τοῦ ὑγροῦ ὁμοία τοῖς θερμαινομένοις ἐστὶν ὕδασιν ὑπὸ πυρός εἰ οὖν μηδὲ τὸ ὑποκαόμενον τρέφεται πῦρ, οὐδὲ τὸν ἥλιον εἰκὸς ἦν ὑπολαβεῖν, οὐδ' εἰ πᾶν θερμαίνων ἐξατμίσειεν τὸ ὕδωρ.	153 Again, when the sun causes the moisture to rise, this is like fire heating water. So, as the fire is not fed by the water above it, it is absurd to suppose that the sun feeds on that moisture, even if its heat made all the water in the world evaporate.
ἄτοπον δὲ καὶ τὸ μόνον φροντίσαι τοῦ ἡλίου, τῶν δ' ἄλλων ἄστρων αὐτοὺς παριδεῖν τὴν σωτηρίαν, τοσούτων καὶ τὸ πλῆθος καὶ τὸ μέγεθος ὄντων.	154 Again, it is absurd, considering the number and size of the stars, that these thinkers should consider the sun only and overlook the question how the rest of the heavenly bodies subsist.
τὸ δ' αὐτὸ συμβαίνει καὶ τούτοις ἄλογον καὶ τοῖς φάσκουσι τὸ πρῶτον ὑγρᾶς οὔσης καὶ τῆς γῆς, καὶ τοῦ κόσμου τοῦ περὶ τὴν γῆν ὑπὸ τοῦ ἡλίου θερμαινομένου, ἀέρα γενέσθαι καὶ τὸν ὅλον οὐρανὸν αὐξηθῆναι, καὶ τοῦτον πνεύματά τε παρέχεσθαι καὶ τὰς τροπὰς αὐτοῦ ποιεῖν φανερῶς γὰρ ἀεὶ τὸ ἀναχθὲν ὁρῶμεν καταβαῖνον πάλιν ὕδωρ κἂν μὴ κατ' ἐνιαυτὸν ἀποδιδῷ καὶ καθ' ἑκάστην ὁμοίως χώραν, ἀλλ' ἔν γέ τισιν τεταγμένοις χρόνοις ἀποδίδωσι πᾶν τὸ ληφθέν, ὡς οὔτε τρεφομένων τῶν ἄνωθεν, οὔτε τοῦ μὲν μένοντος ἀέρος ἤδη μετὰ τὴν γένεσιν, τοῦ δὲ γιγνομένου καὶ φθειρομένου πάλιν εἰς ὕδωρ, ἀλλ' ὁμοίως ἅπαντος διαλυομένου καὶ συνισταμένου πάλιν εἰς ὕδωρ.	155 Again, they are met by the same difficulty as those who say that at first the earth itself was moist and the world round the earth was warmed by the sun, and so air was generated and the whole firmament grew, and the air caused winds and solstices. The objection is that we always plainly see the water that has been carried up coming down again. Even if the same amount does not come back in a year or in a given country, yet in a certain period all that has been carried up is returned. This implies that the celestial bodies do not feed on it, and that we cannot distinguish between some air which preserves its character once it is generated and some other which is generated but becomes water again and so perishes; on the contrary, all the moisture alike is dissolved and all of it condensed back into water.
τὸ μὲν οὖν πότιμον καὶ γλυκὺ διὰ κουφότητα πᾶν ἀνάγεται, τὸ δ' ἁλμυρὸν ὑπομένει διὰ βάρος οὐκ ἐν τῷ αὐτοῦ οἰκείῳ τόπῳ τοῦτο γὰρ οἰητέον ἀπορηθῆναί τε προσηκόντως (ἄλογον γὰρ εἰ μή (355b.) τίς ἐστιν τόπος ὕδατος ὥσπερ καὶ τῶν ἄλλων στοιχείων) καὶ ταύτην εἶναι λύσιν ὃν γὰρ ὁρῶμεν κατέχουσαν τόπον τὴν θάλατταν, οὗτος οὐκ ἔστιν θαλάττης ἀλλὰ μᾶλλον ὕδατος. φαίνεται δὲ θαλάττης, ὅτι τὸ μὲν ἁλμυρὸν ὑπομένει διὰ τὸ βάρος, τὸ δὲ γλυκὺ καὶ πότιμον ἀνάγεται διὰ τὴν κουφότητα, καθάπερ ἐν τοῖς τῶν ζῴων σώμασιν. καὶ γὰρ ἐν τούτοις τῆς τροφῆς εἰσελθούσης γλυκείας ἡ τῆς ὑγρᾶς τροφῆς ὑπόστασις καὶ τὸ περίττωμα φαίνεται πικρὸν ὂν καὶ ἁλμυρόν τὸ γὰρ γλυκὺ καὶ πότιμον ὑπὸ τῆς ἐμφύτου θερμότητος ἑλκυσθὲν εἰς τὰς σάρκας καὶ τὴν ἄλλην σύνταξιν ἦλθεν τῶν μερῶν, ὡς ἕκαστον πέφυκεν. ὥσπερ οὖν κἀκεῖ ἄτοπον εἴ τις τῆς ποτίμου τροφῆς μὴ νομίζοι τόπον εἶναι τὴν κοιλίαν, ὅτι ταχέως ἀφανίζεται, ἀλλὰ τοῦ περιττώματος, ὅτι τοῦθ' ὁρᾷ ὑπομένον, οὐκ ἂν ὑπολαμβάνοι καλῶς. ὁμοίως δὲ καὶ ἐν τούτοις ἔστιν γάρ, ὥσπερ λέγομεν, οὗτος ὁ τόπος ὕδατος διὸ καὶ οἱ ποταμοὶ ῥέουσιν εἰς αὐτὸν ἅπαντες καὶ πᾶν τὸ γιγνόμενον ὕδωρ εἴς τε γὰρ τὸ κοιλότατον ἡ ῥύσις, καὶ ἡ θάλαττα τὸν τοιοῦτον ἐπέχει τῆς γῆς τόπον ἀλλὰ τὸ μὲν ἀναφέρεται ταχὺ διὰ τὸν ἥλιον ἅπαν, τὸ δ' ὑπολείπεται διὰ τὴν εἰρημένην αἰτίαν.	156 The drinkable, sweet water, then, is light and is all of it drawn up: the salt water is heavy and remains behind, but not in its natural place. For this is a question which has been sufficiently discussed (I mean about the natural place that water, like the other elements, must in reason have), and the answer is this. The place which we see the sea filling is not its natural place but that of water. It seems to belong to the sea because the weight of the salt water makes it remain there, while the sweet, drinkable water which is light is carried up. The same thing happens in animal bodies. Here, too, the food when it enters the body is sweet, yet the residuum and dregs of liquid food are found to be bitter and salt. This is because the sweet and drinkable part of it has been drawn away by the natural animal heat and has passed into the flesh and the other parts of the body according to their several natures. Now just as here it would be wrong for any one to refuse to call the belly the place of liquid food because that disappears from it soon, and to call it the place of the residuum because this is seen to remain, so in the case of our present subject. This place, we say, is the place of water. Hence all rivers and all the water that is generated flow into it: for water flows into the deepest place, and the deepest part of the earth is filled by the sea. Only all the light and sweet part of it is quickly carried off by the sun, while the rest remains for the reason we have explained.

Hic incipit inquirere veritatem circa opiniones quas habuerunt antiqui naturales de mari.	147. Here he begins to search into the truth about the opinions which the ancient natural philosophers held about the sea.
Et primo ostendit de quo est intentio: dicens quod est de generatione maris, si est factum; et de sapore eius, quae sit causa salsedinis et amaritudinis ipsius. Secundo ibi: causa quidem igitur etc., exequitur propositum.	First, he shows what his intention is about [126] and says that it is about the generation of the sea: if it was made, and of its savor — as to what is the cause of its salty and bitter taste; Secondly, he pursues the proposition, at 148.
Et dividitur in partes tres:	This is divided into three parts:
in prima determinat de natura maris, utrum scilicet sit naturalis locus aquae; in secunda determinat de generatione eius, utrum scilicet sit factum vel non, ibi, de salsedine autem etc.; in tertia determinat de sapore maris, quare scilicet sit salsum, ibi: de salsedine autem his quidem et cetera.	In the first he determines about the nature of the sea: whether it is the natural place of water, at 148; In the second about its generation: whether or not it was made (L. 4); In the third about its savor: why it is salty (L. 5).
Prima autem pars dividitur in partes duas:	The first part is divided into two parts:
in prima ostendit opinionem antiquorum de natura maris; in secunda obiicit contra eam, ibi: opponitur autem et cetera.	In the first he shows the opinion of the ancients about the nature of the sea, at 148; In the second he objects against it, at 149.
Dicit ergo primo quod antiqui putaverunt quod mare sit principium omnis aquae, et quod sit substantia et corpus totius aquae, quasi mare sit naturalis locus aquae. Et causa inducens eos ad hoc fuit, quod videbatur rationabile esse quod, sicut omnium aliorum elementorum magnitudo est congregata in unum locum, et est unum principium unde derivatur partialiter elementum et commiscetur aliis elementis, propter multitudinem substantiae elementaris in illo loco existentis, ita est in aqua. Videmus enim quod multitudo ignis est in superiori loco huius inferioris mundi, qui est naturalis locus eius; et similiter multitudo aeris est sub loco ignis, quasi in proprio loco congregata; et manifestum est quod corpus terrae est in medio, circa quod omnia alia corpora sunt ordinata. Unde manifestum est quod necesse est etiam, secundum eandem rationem, esse aliquem locum ubi sit congregata multitudo aquae, quasi in loco proprio et naturali.	148. He says therefore first [147] that the ancients thought the sea to be the source of all water, and that it is the substance and body of the totality of water, as though the sea were the natural place of water. And the cause which led them to this was that it seemed reasonable that, just as the main bulk of all other elements is gathered into one place, and there is one source from which are derived those portions of that element which mingle with other elements, due to the size of the elemental substance, so too with water. For we observe that the main body of fire exists in the upper region of this lower world, which is its natural place; likewise, the main body of air exists under the region of fire, as though gathered together in its appropriate place; and it is plain that the body of earth is in the center, around which all other bodies are ordered. Hence it is plain that according to the same reasoning, it is also necessary that there be a place where the main bulk of water be congregated, as in its proper and natural place.
Huiusmodi autem non potest esse aliud quam mare: quia aquae fluviorum non sunt omnes simul, cum tamen oporteat unius elementi esse unum locum continuum. Iterum aqua fluviorum non est stabilis, sed fluens, cum tamen oporteat omne elementum stare in proprio loco: fluit autem fluviorum aqua, utpote quae videtur semper generari, et non quiescere in eodem loco.	Such a place can be naught but the sea: because the waters of streams are not all of them together, whereas for one element there must be one continuous place. Further, the water of rivers is not stationary but flowing, whereas every element must be stable in its proper place — for the water of rivers flows so as to seem to be forever coming into existence and not remaining in the same place.
Propter hanc igitur dubitationem, putaverunt quod mare esset principium omnis aquae et omnium humidorum. Et propter hoc putaverunt quod omnia flumina non solum intrant in mare, sed etiam fluunt a mari: quia locus naturalis alicuius elementi videtur esse principium et terminus motus omnium illorum quae sunt de natura illa, quia omnia naturaliter tendunt ad locum proprium. Et secundum antiquos erat etiam principium: quia ponebant quod elementa erant ingenerabilia et incorruptibilia, unde aqua non generabatur de novo; et sic oportebat quod, ubicumque aqua extra locum proprium inveniretur, quod influeret a naturali loco aquae.	On account of this problem they thought that the sea was the source of all water and of all moist things. On which account they thought that all rivers not only flow into the sea, but from it as well — since the natural place of an element seems to be the source and terminus of the movements of all things that possess its nature, for all things naturally tend to their own place. And according to the ancients it was also the source since they held the elements to be ungenerated and incorruptible — hence water was not newly generated. Thus, wherever water might be found outside its proper place, it would have had to have flowed from the natural place of water.
Et quia posset aliquis obiicere quod mare est salsum, et aqua fluviorum est dulcis, et sic non videtur fluens a mari; ad hanc obiectionem excludendam, subditur quod illud quod est salsum, quando colatur, fit dulce; et sic aqua maris, quando colatur per terram, efficitur potabilis in fluviis.	And because one could object that the sea is salty, whereas the water of rivers is sweet, and consequently does not seem to flow from the sea, they add, to dismiss this objection, that when something salty is filtered, it becomes sweet; and so sea water, when filtered through earth, becomes drinkable in rivers.
Deinde cum dicit: opponitur autem etc., movet quasdam dubitationes circa praedeterminata:	149. Then [148] he raises certain doubts about these previous determinings:
et primo unam contra hoc quod mare est locus naturalis aquae; secundo contra hoc quod dictum est quod mare est terminus aquarum currentium, ibi: quaerere autem antiquam et cetera.	First, a doubt against the sea's being the natural place of water, at 149; Secondly, against the sea's being the terminus of running waters (L. 3).
Circa primum duo facit.	About the first he does two things:
Primo movet dubitationem: quae talis est. Si mare est principium omnis aquae, quasi naturalis locus aquae existens, quare aqua maris non est dulcis et potabilis, sed salsa? Omne enim elementum in primo loco videtur esse intransmutatum, et naturaliter se habens: salsedo autem non est naturalis proprietas aquae, sed ex aliqua transmutatione ei accidit.	First, he raises this doubt [148], which is as follows: If the sea is the source of all water as though it were the natural place of water, why is sea water not sweet and drinkable but salty? For every element in its primal place is seen to be untransformed and in its natural state — while saltiness is not a natural property of water but is due to some transmutations,
Secundo ibi: causa autem simul etc., solvit praedictam dubitationem. Et circa hoc tria facit:	150. Secondly [149], he solves this doubt. In connection with this, he does three things:
primo praemittit quoddam, resumens ex praedeterminatis, quod est necessarium ad solutionem; secundo ex hoc quod propositum est, excludit quandam falsam opinionem, ibi: propter quod et deridendi etc.; tertio solvit dubitationem, ibi: potabile quidem igitur et cetera.	First, from matters already determined he takes something necessary for the solution; Secondly, from what was proposed he dismisses a certain false opinion, at 151; Thirdly, he settles the doubt, at 153.
Dicit ergo primo quod assignando causam praedictae dubitationis, non solum solvetur haec dubitatio, sed necessarium erit per hoc accipere rectam opinionem de mari. Resumit ergo quod aqua est ordinata circa terram, sicut sphaera ignis super aerem, et sphaera aeris super aquam. Ignis enim est supremum elementorum, sive ignis existimetur esse corpus caeleste, ut plurimi dicunt, sive sit quoddam corpus ordinatum sub caelesti corpore, sicut ipse supra dixit. Cum igitur ex solis motu causetur generatio et corruptio, et omnes permutationes in istis inferioribus, oportet quod illud quod est subtilissimum et dulcissimum in aqua rarefacta, evaporans continue feratur in superiorem locum; et ibi iterum condensatum ex virtute frigoris, feratur deorsum in terram. Et hoc semper fit secundum naturam, ut prius dictum est.	He says therefore first [149], that in assigning the cause of this doubt, not only will it be solved, but it will be necessary through it to obtain the correct opinion about the sea. He recalls, therefore, that water is positioned around the earth, as the sphere of fire above the air, and as the sphere of air above the water. For fire is the highest of the elements, whether fire be taken as the heavenly body, as very many hold, or as a body situated under the heavenly body, as he held above. Now, since generation and corruption, and all changes affecting lower bodies, are caused by the movement of the sun, what is finest and sweetest in rarified water must be, as evaporated continually, brought to an upper region, where it is again condensed by the power of the cold and carried downward to earth. And this is always happening by nature, as already stated.
Deinde cum dicit: propter quod et deridendi etc., excludit quandam falsam opinionem per praemissa. Et primo ponit opinionem. Et dicit quod per praedicta patet quod deridendi sunt antiqui, qui dixerunt quod sol cibaretur humido aquoso, et ob hanc causam circumiret, quia idem locus non potest semper praebere huiusmodi alimentum; quod est necessarium ipsum habere, aut, nisi ipsum haberet, corrumperetur. Putabant enim quod sol esset naturae igneae: manifestum est autem quod quandiu ignis habuerit nutrimentum, tandiu durat; solum autem humidum est nutrimentum ignis. Unde, consumpto totaliter humido, extinguitur ignis.	151. Then [150] he uses this to dismiss a false opinion. First, he cites the opinion and says that from the foregoing it is plain that those ancients should be laughed at who said that the sun was fed by the watery moisture, and that it moved about because the same place cannot always offer this nourishment which it must have or be destroyed by not having it. For they thought that the sun was of a fiery nature. Now it is plain that fire lasts only so long as it is fed, and that the moist alone is its food. Consequently, when the moisture is totally consumed, the fire dies out.
Secundo ibi: tanquam pertingat etc., improbat praedictam positionem quinque rationibus. Quarum prima est, quod vapor qui sursum elevatur, non ascendit usque ad locum solis, ut exinde possit cibari. Et hoc satis ex praedictis potest esse manifestum.	152. Secondly [151], he assails this opinion with five reasons. The first is that vapor which is lifted upward does not ascend as far as the sun's place, so as to be its food. This is plain enough from what has been already said.
Secundam rationem ponit ibi: aut ascensus et cetera. Quae est quod ponentes hoc quod dictum est, videntur existimare quod talis sit ascensus vaporis ad solem, qualis est ascensus fumi ad flammam; ex qua acceperunt signum ad sic opinandum de sole. Sed non est simile. Quia flamma non semper manet eadem, sed continue fit nova, per hoc quod materia alia et alia continue inflammatur; quae quidem prius est humida, apta inflammationi, et per ignem totaliter desiccatur, et desinit inflammari, et succedit alia. Et sic patet quod flamma non nutritur: quia quod nutritur oportet manere idem, ut patet in animalibus et plantis; sed flamma quasi nullo tempore permanet, ut dictum est. Sed hoc non potest accidere circa solem: quia si sic nutriretur secundum quod ipsi dicunt, continue innovaretur, et non solum semel in die, sicut posuit Heraclitus.	Then [152] he presents the second reason which is that those who held that opinion seemed to think that the rise of vapor to the sun is as the rise of smoke to a flame: from the latter they took their basis for thinking as they do about the sun. But there is no similarity. For a flame never remains the same individual but is continually becoming a new thing by the fact that other and other material is continually enkindled: the matter, originally moist and suitable for combustion, is completely dried up by the fire and ceases to be inflamed, and is then succeeded by other matter. And so it is plain that a flame is not fed, because what is fed must retain its identity, as is plain in animals and plants, whereas a flame persists as though for no time at all, as has been said. Now such a state of affairs cannot be true of the sun: for if it were fed in the way they claim', it would be re-born continually and not just once every day, as Heraclitus postulated.
Tertiam rationem ponit ibi: adhuc autem et cetera. Et dicit quod elevatio vaporis humidi ad solem, similis est calefactioni aquarum in ollis igne supposito. Ignis autem ardens sub olla non nutritur ab aqua evaporante. Unde nec etiam sol, si faciat evaporare tantam aquam.	He presents the third reason [153] and says that the rising of moist vapor to the sun is akin to the boiling of water in pans over a fire. But the fire burning under the pan is not fed by the evaporating water. Therefore, neither is the sun, if it should cause so much water to evaporate.
Quartam rationem ponit ibi: inconveniens autem et cetera. Et dicit quod inconveniens fuit quod attribuerent tantum soli nutrimentum, et non aliis stellis, ad eorum salutem, cum tamen ponantur ab eis igneae naturae. Quae quidem astra sunt tot et tam magna, quod tota aqua non sufficeret ad nutrimentum eorum.	He presents the fourth reason [153] and says that it is inconsistent to postulate food for the sun only and not for the other stars, if they are to remain healthy, since they too are assumed by them to be of a fiery nature. Indeed, these stars are so many and so large that the totality of water would not be enough to feed them.
Quintam rationem ponit ibi: idem autem accidit et cetera. Et dicit hanc rationem esse communiter et contra istam opinionem, et contra illos qui dixerunt quod a principio tota terra erat cooperta aquis, et postea, aqua vaporante ex calore solis, esse factum aerem; et sic totum caelum est augmentatum, per hoc quod aer, cum sit rarior, plus occupat de loco quam aqua ex qua generatur; et hoc quod sic est resolutum ab aquis, causat ventos et motum caeli. Utraque igitur harum opinionum destruitur per hoc quod manifeste videmus illud quod elevatur sursum ab aquis, iterum redire ad terram; et si non per eundem locum et similiter per omnes regiones (quia aliquando, et in quibusdam regionibus, plus evaporat quam pluat ibi), sed tamen in aliquibus locis, per aliquam ordinationem temporis, omne quod sursum elevatur, redit iterum ad terram. Et sic patet quod neque superiora corpora aluntur ex vaporibus; neque aliqua pars vaporis remanet aer, et alia iterum redit in aquam.	He presents the fifth reason [155] and says that this argument is both against this position and against those who held that in the beginning the entire earth was covered with water, but that later, as the water was evaporated by the sun's heat, air was formed; and as a consequence, the whole heaven grew by the fact that air, being more rarified, occupies more place than the water from which it is generated; what has been thus resolved out of water is the cause of winds and of the heaven's movement. Both, therefore, of these opinions are destroyed by the fact that we plainly see the return to earth, of whatever has been lifted upward from the water. And if it does not return to the same place and equally in all places (for in some regions there is more evaporation than rainfall), yet in various places, according to a certain order of time, all the matter that has been borne aloft returns again to earth. And so it is plainly not so that higher bodies are fed by vapors or that one portion of the vapors remains air and another returns to water.
Deinde cum dicit: potabile quidem igitur etc., ex eo quod supra praemissum est, concludit solutionem praedictae dubitationis. Et dicit quod cum vapor elevetur superius, illud quidem quod est dulce et potabile, totum elevatur superius, propter id quod est levius: illud autem quod est salsum, quia gravius est, manet deorsum, quasi in proprio loco. Hoc enim videtur rationabiliter et convenienter esse dictum in praemissa dubitatione, scilicet quod mare est locus naturalis aquae: irrationabile enim est si aqua non habeat proprium locum naturalem, sicut alia elementa. Sed solutio motae dubitationis contra hoc ex salsedine aquae, est quod locus quem mare occupat, est locus naturalis aquae, inquantum aqua: sed tamen videtur esse locus naturalis aquae maris solum, propter hoc quod salsum manet deorsum propter gravitatem, dulce autem evaporavit sursum propter levitatem.	153. Then [156] he concludes the solution of the aforesaid doubt, and says that since vapor is borne aloft, that which is sweet and drinkable is wholly carried up because of being lighter, whereas that which is salty, being heavier, remains below as in its proper place. For it seems to be reasonably and fittingly held in the difficulty previously set down that the sea is the natural place of water — for it is unreasonable that water should not have a proper natural place as do the other elements. But the solution of the difficulty raised against this from the saltiness of the sea is that the place occupied by the sea is the natural place of water qua water; whereas it seems to be the natural place of sea water only, because that which is salt remains below because of its heaviness, while the sweet is evaporated aloft, because of its lightness.
Et ponit exemplum de eo quod accidit in corporibus animalium. Quia, cum cibus assumptus sit dulcis et humidus, hypostasis quae remanet ex cibo, et superfluum alimenti, apparet amarum et salsum, propterea quia illud quod est dulce, est attractum a calore naturali ad carnem et ad quamlibet partem corporis, sicut quaelibet apta nata est nutriri. Per hoc ergo concludit a simili quod, sicut inconveniens esset si quis putaret quod venter non esset locus cibi, sed solum superfluitatis, quia dum nutriuntur membra, cito sumitur materia cibi, et superfluum remanet; sed tamen iste non bene existimaret, quia, ut prius diximus, iste est locus naturalis cibi, inquantum cibus, et non solum cibi in ventre existentis: similiter et in proposito iste locus occupatus a mari, est locus naturalis aquae. Et omnis aqua movetur ad ipsum tanquam ad locum proprium: fluxus enim aquae est ad id quod est magis concavum, et talis est locus maris. Sed quamvis locus iste sit naturalis aquae, tamen illud quod est dulce, cito fertur sursum, propter solem elevantem vaporem: illud autem quod est salsum, remanet inferius propter praedictam causam.	He gives an example based on what happens in the bodies of animals. Although the food taken in is sweet and moist, the residue that remains of the food, as well as the superfluous nutriment, appears bitter and salty, because the sweet element has been drawn to flesh and to every part of the body by natural heat, according as each several part is naturally apt to be nourished. By analogy to this, he concludes that, just as it would be strange for a person to suppose that the belly is not the place of food but only of the residue, on the ground that when the members are being nourished, the matter of the food is forthwith removed from the belly and the residue remains, and such a person would not be judging wisely, because, as we have already said, it is the natural place of food qua food, and not just of the food present in the belly, so too at present, the place occupied by the sea is the natural place of water. Indeed, all water moves toward the sea as to its proper place; for the flow of water is toward what is more concave, as is the place of the sea. But although this is the natural place of water, yet what is sweet is forthwith borne aloft, because of the sun raising the vapor, while what is salty remains below for the reason already given.

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Lecture 3
Why the sea does not increase. Rejection of Plato's Tartarus

Chapter 2 cont.
τὸ δὲ ζητεῖν τὴν ἀρχαίαν ἀπορίαν, διὰ τί τοσοῦτον πλῆθος ὕδατος οὐδαμοῦ φαίνεται (καθ' ἑκάστην γὰρ ἡμέραν ποταμῶν ῥεόντων ἀναρίθμων καὶ τὸ μέγεθος ἀπλέτων οὐδὲν ἡ θάλαττα γίγνεται πλείων),	157 It is quite natural that some people should have been puzzled by the old question why such a mass of water leaves no trace anywhere (for the sea does not increase though innumerable and vast rivers are flowing into it every day.)
τοῦτο οὐδὲν μὲν ἄτοπον ἀπορῆσαί τινας, οὐ μὴν ἐπιβλέψαντά γε χαλεπὸν ἰδεῖν. τὸ γὰρ αὐτὸ πλῆθος ὕδατος εἰς πλάτος τε διαταθὲν καὶ ἀθρόον οὐκ ἐν ἴσῳ χρόνῳ ἀναξηραίνεται, ἀλλὰ διαφέρει τοσοῦτον ὥστε τὸ μὲν διαμεῖναι ἂν ὅλην τὴν ἡμέραν, τὸ δ' ὥσπερ εἴ τις ἐπὶ τράπεζαν μεγάλην περιτείνειεν ὕδατος κύαθον, ἅμα διανοουμένοις ἂν ἀφανισθείη πᾶν. ὃ δὴ καὶ περὶ τοὺς ποταμοὺς συμβαίνει συνεχῶς γὰρ ῥεόντων ἀθρόων ἀεὶ τὸ ἀφικνούμενον εἰς ἀχανῆ καὶ πλατὺν τόπον ἀναξηραίνεται ταχὺ καὶ ἀδήλως.	158 But if one considers the matter the solution is easy. The same amount of water does not take as long to dry up when it is spread out as when it is gathered in a body, and indeed the difference is so great that in the one case it might persist the whole day long while in the other it might all disappear in a moment—as for instance if one were to spread out a cup of water over a large table. This is the case with the rivers: all the time they are flowing their water forms a compact mass, but when it arrives at a vast wide place it quickly and imperceptibly evaporates.
τὸ δ' ἐν τῷ Φαίδωνι γεγραμμένον περί τε τῶν ποταμῶν καὶ τῆς θαλάττης ἀδύνατόν ἐστιν. λέγεται γὰρ ὡς ἅπαντα μὲν εἰς ἄλληλα συντέτρηται ὑπὸ γῆν, ἀρχὴ δὲ πάντων εἴη καὶ πηγὴ τῶν (356a.) ὑδάτων ὁ καλούμενος Τάρταρος, περὶ τὸ μέσον ὕδατός τι πλῆθος, ἐξ οὗ καὶ τὰ ῥέοντα καὶ τὰ μὴ ῥέοντα ἀναδίδωσιν πάντα τὴν δ' ἐπίρρυσιν ποιεῖν ἐφ' ἕκαστα τῶν ῥευμάτων διὰ τὸ σαλεύειν ἀεὶ τὸ πρῶτον καὶ τὴν ἀρχήν οὐκ ἔχειν γὰρ ἕδραν, ἀλλ' ἀεὶ περὶ τὸ μέσον εἱλεῖσθαι κινούμενον δ' ἄνω καὶ κάτω ποιεῖν τὴν ἐπίχυσιν τοῖς ῥεύμασιν. τὰ δὲ πολλαχοῦ μὲν λιμνάζειν, οἷον καὶ τὴν παρ' ἡμῖν εἶναι θάλατταν, πάντα δὲ πάλιν κύκλῳ περιάγειν εἰς τὴν ἀρχήν, ὅθεν ἤρξαντο ῥεῖν, πολλὰ μὲν κατὰ τὸν αὐτὸν τόπον, τὰ δὲ καὶ καταντικρὺ τῇ θέσει τῆς ἐκροῆς, οἷον εἰ ῥεῖν ἤρξαντο κάτωθεν, ἄνωθεν εἰσβάλλειν. εἶναι δὲ μέχρι τοῦ μέσου τὴν κάθεσιν τὸ γὰρ λοιπὸν πρὸς ἄναντες ἤδη πᾶσιν εἶναι τὴν φοράν. τοὺς δὲ χυμοὺς καὶ τὰς χρόας ἴσχειν τὸ ὕδωρ δι' οἵας ἂν τύχωσι ῥέοντα γῆς.	159 But the theory of the Phaedo about rivers and the sea is impossible. There it is said that the earth is pierced by intercommunicating channels and that the original head and source of all waters is what is called Tartarus—a mass of water about the centre, from which all waters, flowing and standing, are derived. This primary and original water is always surging to and fro, and so it causes the rivers to flow on this side of the earth's centre and on that; for it has no fixed seat but is always oscillating about the centre. Its motion up and down is what fills rivers. Many of these form lakes in various places (our sea is an instance of one of these), but all of them come round again in a circle to the original source of their flow, many at the same point, but some at a point opposite to that from which they issued; for instance, if they started from the other side of the earth's centre, they might return from this side of it. They descend only as far as the centre, for after that all motion is upwards. Water gets its tastes and colours from the kind of earth the rivers happened to flow through.
συμβαίνει δὲ τοὺς ποταμοὺς ῥεῖν οὐκ ἐπὶ ταὐτὸν ἀεὶ κατὰ τὸν λόγον τοῦτον ἐπεὶ γὰρ εἰς τὸ μέσον εἰσρέουσιν ἀφ' οὗπερ ἐκρέουσιν, οὐδὲν μᾶλλον ῥευσοῦνται κάτωθεν ἢ ἄνωθεν, ἀλλ' ἐφ' ὁπότερ' ἂν ῥέψῃ κυμαίνων ὁ Τάρταρος. καίτοι τούτου συμβαίνοντος γένοιτ' ἂν τὸ λεγόμενον ἄνω ποταμῶν ὅπερ ἀδύνατον.	160 But on this theory rivers do not always flow in the same sense. For since they flow to the centre from which they issue forth they will not be flowing down any more than up, but in whatever direction the surging of Tartarus inclines to. But at this rate we shall get the proverbial rivers flowing upwards, which is impossible.
ἔτι τὸ γιγνόμενον ὕδωρ καὶ τὸ πάλιν ἀναγόμενον πόθεν ἔσται; τοῦτο γὰρ ἐξαίρειν ὅλον ἀναγκαῖον, εἴπερ ἀεὶ σῴζεται τὸ ἴσον ὅσον γὰρ ἔξω ῥεῖ, πάλιν ῥεῖ πρὸς τὴν ἀρχήν.	161 Again, where is the water that is generated and what goes up again as vapour to come from? For this must all of it simply be ignored, since the quantity of water is always the same and all the water that flows out from the original source flows back to it again.
καίτοι πάντες οἱ ποταμοὶ φαίνονται τελευτῶντες εἰς τὴν θάλατταν, ὅσοι μὴ εἰς ἀλλήλους εἰς δὲ γῆν οὐδείς, ἀλλὰ κἂν ἀφανισθῇ, πάλιν ἀναδύνουσιν.	162 This itself is not true, since all rivers are seen to end in the sea except where one flows into another. Not one of them ends in the earth, but even when one is swallowed up it comes to the surface again.
μεγάλοι δὲ γίγνονται τῶν ποταμῶν οἱ μακρὰν ῥέοντες διὰ κοίλης πολλῶν γὰρ δέχονται ῥεύματα ποταμῶν, ὑποτεμνόμενοι τῷ τόπῳ καὶ τῷ μήκει τὰς ὁδούς διόπερ ὅ τ' Ἴστρος καὶ ὁ Νεῖλος μέγιστοι τῶν ποταμῶν εἰσιν τῶν εἰς τήνδε τὴν θάλατταν ἐξιόντων. καὶ περὶ τῶν πηγῶν ἄλλοι λέγουσιν ἑκάστου τῶν ποταμῶν ἄλλας αἰτίας διὰ τὸ πολλοὺς εἰς τὸν αὐτὸν ἐμβάλλειν.	163 And those rivers are large which flow for a long distance through a lowying country, for by their situation and length they cut off the course of many others and swallow them up. This is why the Istrus and the Nile are the greatest of the rivers which flow into our sea. Indeed, so many rivers fall into them that there is disagreement as to the sources of them both.
ταῦτα δὴ πάντα φανερὸν ὡς ἀδύνατόν ἐστι συμβαίνειν ἄλλως τε καὶ τῆς θαλάττης ἐκεῖθεν τὴν ἀρχὴν ἐχούσης.	164 All of which is plainly impossible on the theory, and the more so as it derives the sea from Tartarus.
ὅτι μὲν οὖν ὕδατός τε ὁ τόπος ἐστὶν οὗτος καὶ οὐ θαλάττης, καὶ διὰ τίν' αἰτίαν τὸ μὲν πότιμον ἄδηλον πλὴν ῥέον, τὸ δ' ὑπομένον, καὶ διότι τελευτὴ (356b.) μᾶλλον ὕδατος ἢ ἀρχή ἐστιν ἡ θάλαττα, καθάπερ τὸ ἐν τοῖς σώμασιν περίττωμα τῆς τροφῆς πάσης, καὶ μάλιστα τὸ τῆς ὑγρᾶς, εἰρήσθω τοσαῦθ' ἡμῖν.	165 Enough has been said to prove that this is the natural place of water and not of the sea, and to explain why sweet water is only found in rivers, while salt water is stationary, and to show that the sea is the end rather than the source of water, analogous to the residual matter of all food, and especially liquid food, in animal bodies.

Hic philosophus movet aliam dubitationem, contra hoc quod dictum est quod mare est terminus fluviorum. Et circa hoc tria facit.	154. Here the Philosopher raises another doubt, against the position that the sea is the terminal of rivers. About this he does three things:
Primo movet dubitationem, quam dicit esse antiquam: propter quid scilicet, cum singulis diebus flumina et innumerabilia numero et immensa magnitudine intrent in mare, non tamen videtur crescere; et hoc in ipso non apparet, quod tanta multitudo aquae ad ipsum deveniat.	First, he raises the doubt which he says is an old one [157]: namely, why is it that, whereas rivers without number and of immense size enter the sea every day, it does not seem to grow and gives no evidence that such a vast amount of water is flowing into it?
Secundo ibi: hoc quidem nullum etc., solvit dubitationem. Et dicit quod, licet non sit inconveniens quod sint aliqui qui circa hoc dubitent, tamen, si quis recte consideret, non est difficile videre solutionem huius. Quia si aliqua aqua diffundatur per aliquam latitudinem, supposito quod sit eadem multitudo aquae in diversis locis diffusa, si non sit eadem quantitas latitudinis, non est aequale tempus desiccationis aquae effusae; sed erit differentia ex diversitate latitudinis in qua aqua diffunditur, quod aliquando manet aqua et non exsiccatur per totum diem, aliquando autem statim ad oculum exsiccatur; sicut si aliquis unum scyphum aquae diffunderet super magnam mensam, statim tota aqua assiccaretur, si autem in aliquo parvo loco tantum de aqua proiiceretur, diu conservaretur. Sic igitur accidit circa fluvios et mare: nam totum quod ex fluviis ad mare pervenit, dispergitur in locum maximae latitudinis, et cito insensibiliter desiccatur per continuam evaporationem aquae, de qua supra dictum est.	155. Secondly [158], he solves the problem and says that, although it is not unfitting that some should be puzzled at this, yet, after careful consideration, it is not difficult to see the solution. Thus, if an amount of water is poured over a certain surface, and the same volume is poured out in different areas, then, if the size of the surface is not the same, the time required for the drying-up of the water poured out is not equal, but there will be a difference arising from the difference of surface on which the water is poured, so that sometimes the water remains and does not dry up for a whole day, while sometimes it dries up under one's very eyes. For example, if someone should pour a cup of water upon a large table, all the water would dry up at once; but if the same amount were poured into some small place, it would be preserved for a long time. This is what happens with rivers and the sea: for the total water coming from the rivers to the sea is spread out over an area of the greatest latitude, and is forthwith imperceptibly dried up by the continuous evaporation of water, concerning which we spoke above.
Tertio ibi: quod autem scriptum est in Phaedone etc., excludit quandam falsam solutionem praedictae dubitationis.	156. Thirdly [159], he excludes a certain false solution to this problem.
Et primo ponit ipsam solutionem. Et dicit quod impossibile est esse verum quod a Platone de mari et fluviis dicitur in libro suo qui intitulatur Phaedo. Dicit enim ibi quod omnia flumina et mare concurrunt sub terra ad aliquod principium, quasi terra sit perforata a mari et fluviis. Hoc autem principium, quod secundum ipsum est principium aquarum omnium, vocatur Tartarus, qui est quaedam magna multitudo aquae existens circa medium mundi: ex quo quidem principio dicit prodire omnes aquas quae non fluunt, sicut sunt mare et stagna, et quae fluunt, sicut fontes et flumina. Dicit autem quod Tartarus undique fluit ad singula rheumatum, idest ad singulos discursus aquarum: quod ideo contingit, quia illud principium aquarum semper movetur. Et hoc ideo, quia non habet aliquem locum fixum in quo quiescat, sed semper movetur circa medium, quasi vacillans hinc inde. Et sic, dum movetur sursum, facit effusionem rheumatum, idest discursus marium et fluviorum, non tantum versus istam partem terrae quam nos habitamus; sed ex multis aliis partibus terrae effundit et alia stagna, quale est mare quod est apud nos.	First, he gives the solution and says that what Plato says about the sea and rivers in his book entitled the Phaedo, cannot be true. For he says there that all rivers and the sea meet at a source under the earth, as though the earth were perforated by the sea and rivers. This source, which according to him, is the source of all waters, is called "Tartarus," a certain vast body of water existing about the center of the world: from it, he says, come all the waters that do not flow, such as the sea and ponds, and waters that do flow, such as springs and rivers. He says further that Tartarus flows in every direction to each of the rheums," i.e., to each of the streams of water. This happens because that source of all waters is forever in motion, for it has no fixed place in which to rest but is forever in motion about the center, as though wandering to and fro. Thus, when it is surging upward, it produces the "flowing out of rheums," i.e., the streaming of seas and rivers, not only toward that portion of the earth we inhabit; but from many other parts of the earth it pours out other bodies of still water, akin to the sea which exists among us.
Sed omnia maria et flumina quadam circulatione reducuntur ad illud principium unde primo effluxerunt, sed diversimode. Nam quaedam redeunt secundum eundem locum secundum quem effluxerunt, ut sit quidam motus reflexus: quaedam vero ex contraria parte redeunt parti unde effluxerant, ut, puta, si effluxerunt de subtus, reingrederentur desuper. Non est tamen sic intelligendum de subtus et desuper, quod aliquid possit esse subtus respectu medii, in quo ponitur primum principium aquarum: quia a superficie terrae usque ad medium, est descensus, sed de cetero, si secundum rectam lineam ultra procederet aqua, esset motus ad sursum; idem enim est moveri a medio, et moveri sursum.	But all seas and rivers are brought back by a certain cycle to that source whence they emerged, but in various ways. For some return according to the same place whence they flowed out, by a kind of reflex movement; others return along a route contrary to the one along which they emerged, so that, for example, if they emerged from beneath, they would flow back from above. We should not so think of "above" and "beneath" as to think that something could be beneath with respect to the center in which the primal source of waters is postulated: for from the surface of the earth to the center, there is a descent; but further, if the water should proceed beyond in a straight line, the course would be upward — movement from the center being the same as movement upward.
Et secundum hoc facile est assignare causam diversitatis colorum et saporum in aquis: quia aqua fluens recipit colorem et saporem secundum modum terrae per quam effluit.	And according to this it is easy to assign a cause for the various colors and tastes of water: because the flowing water acquires its color and taste from the type of earth through which it flows out.
Secundo ibi: accidit ergo fluvios etc., improbat praedictam positionem quinque rationibus.	157. Secondly [160], he disposes of the aforesaid position with five reasons.
Quarum prima est quod, cum quandoque flumina redeant per eandem viam, quandoque autem per contrariam, sequitur secundum hanc positionem quod fluviorum fluxus non semper fit ad eandem partem. Quia enim redeunt ad medium a quo fluxerunt, non magis fluent subtus quam supra, comparando superficiem terrae ad medium, quod semper intelligitur: a superficie terrae vocatur aliquid sursum et aliquid deorsum, propter altitudinem et demissionem. Si enim motus fluviorum causatur ex effluentia Tartari, effluentia autem Tartari est ad omnem partem, sequitur quod aqua, quasi impulsa a Tartaro, indifferenter fluat ad quamlibet partem, sicut et Tartarus fluctuans tendit ad omnem partem. Et sic accidet illud quod dicitur in proverbio, sursum fluviorum, scilicet quod flumina sint superiora fontibus, vel quod sursum fluant: et hoc est impossibile.	The first is that, since sometimes the rivers return by the same route and sometimes by a contrary one, it follows, according to this position, that the flow of rivers is not consistently in the same direction. For since they return to the center from which they flowed, they will not flow "below" any more than "above," if you compare the surface of the earth to the center, as is always understood. But in relation to the surface of the earth something is "up," and something "down," depending on height and depth. If the movement of rivers is caused from Tartarus' overflow and this overflow is in every direction, it follows that the water, impelled, as it were, by Tartarus, flows indiscriminately in every direction, just as Tartarus in its fluctuation goes in every direction. Consequently, what is said in the proverb will come to pass, namely, an "up" of rivers, i.e., rivers that are higher than the springs or that flow uphill — which is impossible.
Secundam rationem ponit ibi: adhuc quae fit aqua etc.: quae talis est. Secundum praedictam positionem, videtur quod oporteat semper aequalem aquam salvari: quia quantum fluit de aqua a Tartaro, tantum ponit quod iterum refluat ad principium. Et sic oportet totaliter excludere generationem aquae in aere, et elevationem aquae a terra per evaporationem: quod patet esse falsum.	He presents the second reason [161], namely, that, according to the aforesaid position, it is seen that it would be necessary that an equal amount of water be always preserved — for he posits that as much water as flows from Tartarus returns to the source. Consequently, one must entirely exclude generation of water in the air and elevation of water from the earth by vaporizing — which is plainly false.
Tertiam rationem ponit ibi: quamvis omnes fluvii et cetera. Et est quod omnes fluvii terminantur ad mare, quicumque non terminantur ad alios fluvios; et nullum flumen est sic terminatum ad terram, quasi terram perforans, quod vadat ad Tartarum; sed si sunt aliqua flumina intrantia in concavitatem terrae, iterum exeunt in aliquo loco. Et sic non videtur verum quod flumina iterum redeant ad Tartarum.	He presents the third reason [162], namely, that all rivers end at the sea which do not terminate at other rivers, and no river so ends in the earth as though perforating the earth and going to Tartarus. Indeed, if there are any rivers entering into the concavity of the earth, they emerge again at some other spot. Consequently, it is not seen to be true that rivers return to Tartarus.
Quartam rationem ponit ibi: magni autem fiunt etc.: quae talis est. Si cursus fluviorum causatur ex effluentia Tartari, oporteret quod ab ipso sui principio flumina multitudinem aquae haberent. Sed hoc non videmus: quia inter fluvios illi inveniuntur magni, qui per longam viam fluunt, eo quod recipiunt discursiones multorum fluviorum, et detruncant vias eorum et secundum locum, quia sunt profunda magis et magis concava, et secundum longitudinem, quia longiorem viam currunt. Et ideo Ister, idest Danubius, et Nilus sunt maximi fluviorum qui in mare Mediterraneum exeunt; et de fontibus eorum diversi diversa dicunt, propter diversitatem fluviorum qui in hos intrant.	The fourth reason which he presents [163] is this: if the course of rivers is caused by what flows out of Tartarus, it would be necessary that rivers have a vast abundance of water from the very start. But this we do not observe: among rivers, those are found to be large which flow a long course, since they receive the flowings of many rivers and cut off their route both as to place, because they are deeper and more concave, and as to length, because they follow a longer course. This is why the Ister, i.e., the Danube, and the Nile are the largest rivers flowing into the Mediterranean Sea, and concerning their sources different ones say different things, because of the variety of rivers that enter them.
Quintam rationem ponit ibi: haec itaque et cetera. Et est quod, ultra praedicta inconvenientia, est etiam hoc, quod sequeretur quod mare habeat principium a Tartaro. Quod inconveniens est: quia mare videtur esse locus naturalis aquarum, sicut supra dictum est.	He presents the fifth reason [164], namely, that over and above the unacceptable aspects already indicated, there is also the fact that it would follow that the sea has its source from Tartarus. And this is not fitting, because, as has been said, the sea is seen to be the natural place of water.
Tertio ibi: quod quidem igitur etc., recolligit quae supra dicta sunt. Et dicit quod tanta dicta sint de hoc quod locus iste quem mare occupat, est locus naturalis aquae, et non solum locus naturalis maris, idest aquae salsae existentis. Et dictum est quare illud quod est potabile et dulce, non manifestatur in mari, sed in aquis fluentibus; illud autem quod salsum est, subsidet in mari, quasi derelictum post evaporationem eius quod erat potabile et dulce. Et dictum est etiam quod mare magis est terminus aquarum quam principium: quia scilicet aqua extra mare generatur, et sursum in aere, ut dictum est de generatione pluviarum, et intra terram, ut dictum est de generatione fontium et fluviorum; et tamen, ubicumque generatur aqua, fluit ad mare, nisi impediatur. Et sic aqua salsa se habet sicut illud quod est superfluum alimenti in corporibus animalium: nam superfluum alimenti est salsum vel amarum. Quod verum est de superfluo cuiuslibet alimenti, sed maxime de superfluo alimenti humidi, sicut urina, quae est magis indigesta, et ideo est magis amara et salsa, ut patet.	158. Thirdly [165], he brings together what has been said above. And he says that so much has been said about the fact that the place which the sea occupies is the natural place of water and not just the natural place of the "sea," i.e., of salt water. And it has been stated why what is drinkable and sweet does not show up in the sea but does in flowing water: what is salty subsides in the sea, being, as it were, the residue from the evaporation of what is drinkable and sweet. Furthermore, it has been said that the sea is rather the end than the source of waters: since, namely, water is generated outside the sea, both in the air above (as was said of the generation of rain), and within the earth (as was said of the generation of springs and rivers); nevertheless, no matter where it is generated, water flows to the sea, unless it is prevented. And thus, salt water is akin to the residue of food in the bodies of animals: for the residue of food is salty and bitter. This is true of the residue of any food, but especially of moist food, as in the case of urine, which is more undigested and therefore more bitter and salty, as is evident.

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Lecture 4
Whether the sea always, was, and always will be

Chapter 3
περὶ δὲ τῆς ἁλμυρότητος αὐτῆς λεκτέον, καὶ πότερον αἰεί ἐστιν ἡ αὐτή, ἢ οὔτ' ἦν οὔτ' ἔσται ἀλλ' ὑπολείψει καὶ γὰρ οὕτως οἴονταί τινες.	166 We must now explain why the sea is salt, and ask whether it eternally exists as identically the same body, or whether it did not exist at all once and some day will exist no longer, but will dry up as some people think.
τοῦτο μὲν οὖν ἐοίκασι πάντες ὁμολογεῖν, ὅτι γέγονεν, εἴπερ καὶ πᾶς ὁ κόσμος ἅμα γὰρ αὐτῆς ποιοῦσι τὴν γένεσιν. ὥστε δῆλον ὡς εἴπερ ἀίδιον τὸ πᾶν, καὶ περὶ τῆς θαλάττης οὕτως ὑποληπτέον.	167 Every one admits this, that if the whole world originated the sea did too; for they make them come into being at the same time. It follows that if the universe is eternal the same must be true of the sea.
τὸ δὲ νομίζειν ἐλάττω τε γίγνεσθαι τὸ πλῆθος, ὥσπερ φησὶ Δημόκριτος, καὶ τέλος ὑπολείψειν, τῶν Αἰσώπου μύθων οὐδὲν διαφέρειν ἔοικεν ὁ πεπεισμένος οὕτως καὶ γὰρ ἐκεῖνος ἐμυθολόγησεν ὡς δὶς μὲν ἡ Χάρυβδις ἀναρροφήσασα τὸ μὲν πρῶτον τὰ ὄρη ἐποίησεν φανερά, τὸ δὲ δεύτερον τὰς νήσους, τὸ δὲ τελευταῖον ῥοφήσασα ξηρὰν ποιήσει πάμπαν. ἐκείνῳ μὲν οὖν ἥρμοττεν ὀργιζομένῳ πρὸς τὸν πορθμέα τοιοῦτον εἰπεῖν μῦθον, τοῖς δὲ τὴν ἀλήθειαν ζητοῦσιν ἧττον	168 Any one who thinks like Democritus that the sea is diminishing and will disappear in the end reminds us of Aesop's tales. His story was that Charybdis had twice sucked in the sea: the first time she made the mountains visible; the second time the islands; and when she sucks it in for the last time she will dry it up entirely. Such a tale is appropriate enough to Aesop in a rage with the ferryman, but not to serious inquirers.
δι' ἣν γὰρ αἰτίαν ἔμεινε τὸ πρῶτον, εἴτε διὰ βάρος, ὥσπερ τινὲς καὶ τούτων φασίν (ἐν προχείρῳ γὰρ τούτου τὴν αἰτίαν ἰδεῖν), εἴτε καὶ δι' ἄλλο τι, δῆλον ὅτι διὰ τοῦτο διαμένειν ἀναγκαῖον καὶ τὸν λοιπὸν χρόνον αὐτήν. ἢ γὰρ λεκτέον αὐτοῖς ὅτι οὐδὲ τὸ ἀναχθὲν ὕδωρ ὑπὸ τοῦ ἡλίου ἥξει πάλιν, ἢ εἴπερ τοῦτ' ἔσται, ἀναγκαῖον ἤτοι ἀεὶ ἢ μέχρι οὗπερ ἂν ᾖ τοῦτο ὑπολείπεσθαι τὴν θάλατταν, καὶ πάλιν ἀναχθῆναι ἐκεῖνο πρότερον δεήσει τὸ πότιμον. ὥστε οὐδέποτε ξηρανεῖται πάλιν γὰρ ἐκεῖνο φθήσεται καταβὰν εἰς τὴν αὐτὴν τὸ προανελθόν διαφέρει γὰρ οὐδὲν ἅπαξ τοῦτ' εἰπεῖν ἢ πολλάκις. εἰ μὲν οὖν τὸν ἥλιον παύσει τις τῆς φορᾶς, τί ἔσται τὸ ξηραῖνον; εἰ δ' ἐάσει εἶναι τὴν περιφοράν, ἀεὶ πλησιάζων τὸ πότιμον, καθάπερ εἴπομεν, ἀνάξει, ἀφήσει δὲ πάλιν ἀναχωρῶν.	169 Whatever made the sea remain at first, whether it was its weight, as some even of those who hold these views say (for it is easy to see the cause here), or some other reason—clearly the same thing must make it persist for ever. They must either deny that the water raised by the sun will return at all, or, if it does, they must admit that the sea persists for ever or as long as this process goes on, and again, that for the same period of time that sweet water must have been carried up beforehand. So the sea will never dry up: for before that can happen the water that has gone up beforehand will return to it: for if you say that this happens once you must admit its recurrence. If you stop the sun's course there is no drying agency. If you let it go on it will draw up the sweet water as we have said whenever it approaches, and let it descend again when it recedes.
ἔλαβον δὲ ταύτην τὴν διάνοιαν κατὰ τῆς θαλάττης ἐκ τοῦ πολλοὺς τόπους φαίνεσθαι ξηροτέρους νῦν ἢ πρότερον περὶ οὗ τὴν αἰτίαν εἴπομεν, ὅτι τῶν κατά τινα χρόνον ὑπερβολῶν γιγνομένων ὕδατος τοῦτ' ἐστὶν τὸ πάθος, ἀλλ' οὐ διὰ τὴν τοῦ παντὸς γένεσιν καὶ τῶν μορίων καὶ πάλιν γ' ἔσται τοὐναντίον καὶ (357a.) ὅταν γένηται, ξηρανεῖται πάλιν καὶ τοῦθ' οὕτως κατὰ κύκλον ἀναγκαῖον ἀεὶ βαδίζειν μᾶλλον γὰρ οὕτως εὔλογον ὑπολαβεῖν ἢ διὰ ταῦτα τὸν οὐρανὸν ὅλον μεταβάλλειν. ἀλλὰ περὶ μὲν τούτων πλείω τῆς ἀξίας ἐνδιατέτριφεν ὁ λόγος	170 This notion about the sea is derived from the fact that many places are found to be drier now than they once were. Why this is so we have explained. The phenomenon is due to temporary excess of rain and not to any process of becoming in which the universe or its parts are involved. Some day the opposite will take place and after that the earth will grow dry once again. We must recognize that this process always goes on thus in a cycle, for that is more satisfactory than to suppose a change in the whole world in order to explain these facts. But we have dwelt longer on this point than it deserves.

Postquam philosophus determinavit de natura maris, ostendens quod est locus naturalis aquae, hic inquirit de generatione ipsius.	159. After determining the nature of the sea, showing that it is the natural place of water, the Philosopher here inquires into its generation.
Et primo dicit de quo est intentio. Et dicit quod dicendum est de salsedine maris; et iterum utrum mare est sempiternum, aut fuit aliquod tempus quando non erat mare, et erit aliquod tempus quo non erit, sed totaliter deficiet.	First, he indicates his intention [166], and says that we must speak about the salt of the sea, and furthermore, about whether the sea is eternal or whether there was a time when the sea was not, and there will be a time when the sea will not be, but will completely cease.
Secundo ibi: etenim sic putant quidam etc., prosequitur propositum, destruendo opiniones aliorum circa hoc.	160. Secondly, he pursues the proposition by disproving the theories of others on this matter:
Et primo destruit opiniones antiquorum; secundo excludit rationem eorum, ibi: acceperunt autem suspicionem hanc et cetera.	First, he disproves the theories of the ancients; Secondly, he excludes their reason, at 163.
Circa primum duo facit.	About the first he does two things:
Primo destruit opiniones antiquorum de incoeptione maris. Et dicit quod quidam putaverunt quod mare non semper fuit, sed quandoque incoepit: et posuerunt etiam quod totus mundus esse incoepit per generationem quandam, dicentes quod simul generatum est mare cum mundo. Et hoc rationabiliter: quia cum mare sit aliquo modo locus aquae, quae est unum elementum, oportet quod sit de principalibus partibus mundi; et ideo quandocumque fuit mundus, fuit mare. Et ideo, sicut illi argumentantur quod, quia mundus genitus est, et mare sit generatum, ita possumus e converso argumentari quod, si mundus est perpetuus, et mare sit perpetuum. Quod autem mundus sit perpetuus, praesupponit ex his quae probavit in libro Physic. et in libro de caelo; quamvis hoc sit falsum et alienum a fide, ut supra dictum est.	First, he disproves the theories of the ancients about the sea's coming into existence [167] and says that some have thought that the sea has not always existed but began to exist at some time. They also posited that the entire world began to exist as the result of some process of generation and stated that the sea began with the world. This was not unreasonable, since, the sea being in a sense the place of water, which is one element, it must be among the principal parts of the world. Hence, whenever the world existed, the sea did. And therefore, just as they argue that, because the world was generated, the sea was generated, so we can argue conversely, that if the world is perpetual, so too is the sea. But that the world is perpetual, he presupposes from what he proved in the Physics and in On the Heavens — although this is false and alien to the faith, as was said above.
Secundo ibi: putare autem minus etc., destruit opiniones antiquorum de defectu maris. Et primo comparat opinionem istam opinionibus fabulosis. Et dicit quod putare hoc quod mare fiat minus secundum quantitatem, et tandem deficiat, secundum quod dixit Democritus, non differt a fabulosis opinionibus Aesopi, qui dixit fabulose quod Charybdis, quae est quaedam vorago in mari, bis absorbuit mare; ita quod ante aqua totam terram circumdabat, vorago autem tantum de aqua absorbuit, quod montes apparuerunt discooperti ab aquis, et terra quae interiacet montibus; secundo autem tantum de aqua absorbuit, quod apparuerunt insulae; ultimo autem absorbebit totam aquam maris, et sic undique remanebit terra arida sine mari. Sed licet componere fabulam talem congrueret Aesopo fabularum inventori, qui hoc dixit dum forte esset iratus ad porthmeum, idest ad quendam portum vel litus maris, ut, iratus aquis, quasi fingeret eas omnes esse absorbendas; tamen talia dicere philosophis inquirentibus veritatem minus convenit.	161. Secondly [168], he disproves the opinions of the ancients about the disappearance of the sea. First he compares this theory to fables. And he says that to think that the sea will diminish in size and at length disappear, as Democritus said, is no different than the ideas in the fables of Aesop, who stated in a fable that Charybdis, a certain deep chasm in the sea, has twice absorbed the sea, in such a manner that previously water covered the entire earth, and this chasm imbibed enough water for the mountains to appear, having been uncovered from the water, and also the land between them; the second time it took in enough for islands to appear; the final time, it will swallow all the water of the sea, and thus there will everywhere remain dry land without the sea. But although to compose such a fable befits Aesop, the inventor of fables, who uttered this one when perhaps in a fit of anger with a "porthmeum," i.e., some harbor or seashore, so that, being angry with the waters, he pretended that all waters were destined to be swallowed up, yet, the utterance of such tales is less fitting for philosophers seeking the truth.
Secundo ibi: propter quam causam etc., improbat praedictam positionem per rationem. Et dicit quod propter quamcumque causam aqua maris primo mansit circa terram, oportebit quod semper maneat: sive dicatur quod hoc accidit propter gravitatem aquae, quae pondere suo hoc habet quod subsideat aeri et praeemineat terrae, (quae quidem causa est vera et manifesta); sive quaecumque alia causa sit, propter hoc oportet quod, si aliquando fuit aqua maris super terram, quod semper maneat. Quia aliter, si hoc non esset, oporteret eos dicere quod aqua quae elevatur a sole evaporata, non redeat iterum ad terram; cuius contrarium manifeste videmus in pluviis. Aut si aqua elevata redit, necesse est vel quod semper duret mare, si aqua semper elevatur et redit; aut quod remaneat quandiu hoc fuerit, quod aqua redit. Et iterum oportebit ferri sursum per evaporationem illud quod est potabile in aqua. Et sic nunquam exsiccabitur mare in tali alternatione: quia iterum aqua descendet in mare.	162. Secondly [169], he disproves the aforesaid theory with a reason. And he says that whatever be the cause on account of which water first surrounded the earth, it will necessarily remain forever: whether it be said that this happens on account of the heaviness of water, whose weight makes it abide beneath the air and above the earth (which, indeed, is the true and manifest cause), or whatever else the cause may be, nevertheless, because of this, it must be that, if the water of the sea was at some time on the earth, it remain forever. For otherwise, if this were not so, they would have to say that the evaporated water borne aloft by the sun, does not return again to earth (the opposite of which is plain in the case of rain). Or, if the elevated water returns, it must needs be either that the sea always abide, if water is forever borne aloft and returns, or that it abide so long as the phenomenon of water returning shall continue. Further, it will be necessary for that which is drinkable in water to be borne aloft by evaporation. Consequently, the sea will never grow dry in such an alternation — since the water will return once more to the sea.
Et non differt utrum hoc semel fiat, scilicet quod aqua elevata iterum descendat, aut fiat saepe: quia utroque modo non minuitur aliquid de aqua. Quia scilicet posset dici quod haec alternatio non semper erit, motu solis cessante, ideo subiungit quod si aliquis dicat quod motus solis cesset, non remanebit aliquid quod possit exsiccare aquam maris: si autem motus solis semper maneat, oportebit quod semper sol, appropinquans ad aliquam partem terrae, elevet per evaporationem aquam; et quando longius recedit, eam cadere propter frigiditatem. Et sic non potest dici quod mare totaliter exsiccetur, sive motus solis cesset sive non.	And it makes no difference whether this happens once, namely, that the elevated water descend again, or a number of times: for in either case, no water is lost. Because it could, however, be claimed that this alternating process will not last forever, if the movement of the sun were to cease, he therefore adds that if anyone should say that the motion of the sun will cease, there will be nothing left to cause the sea's drying up; but if the motion of the sun abides forever, then it will always be necessary that the sun, as it approaches some region of the earth, lift up water by evaporation, and, when it departs from that region, that the water should fall, by reason of the cold. And so it cannot be said that the sea will entirely dry out, whether the motion of the sun continues or ceases.
Deinde cum dicit: acceperunt autem suspicionem hanc etc., excludit rationem moventem eos ad hoc ponendum. Et dicit quod acceperunt hanc opinionem, quod scilicet totaliter exsiccaretur mare, et quod quandoque incoeperit, propter hoc quod multa loca apparent magis sicca nunc quam prius. Sed causa propter quam accidit haec passio, dicta est prius, quia scilicet secundum quaedam determinata tempora fiunt excessus aquarum: sed non accidit propter hoc quod totum universum generetur; sed eius partes generantur. Et iterum secundum alia determinata tempora erit contrarium, scilicet quod erit magnus excessus siccitatis; quod cum factum fuerit, iterum desiccabitur terra, quae erat cooperta aquis propter excessum aquarum prius factum. Et necesse est quod hoc semper procedat circulariter, scilicet quod post excessum aquarum, determinato tempore, fiat excessus siccitatis, et e converso. Rationabilius enim est sic opinari, quam ponere quod totum caelum permutetur, propter quasdam particulares permutationes existentes circa terram.	163. Then [170] he dismisses the reason moving them to posit their theory. And he says that they took up this theory (namely, that the sea would become wholly dry, and that it began at some time to exist), because there are many places that seem drier now than formerly. But the cause of this passion has not been given before, namely, the fact that at certain determinate times an excess of water is produced, and not because the universe as a whole is in the process of becoming — although its parts are. Then, at other determinate times, the contrary will come to pass, namely, there will be an excessive drought. When this shall have come about, the land will again be dried out which had been covered with water by the previous excess of water. And it is necessary that this proceed always in a cyclic way, namely, that after an excess of water there be, at a definite time, an excess of dryness, and vice-versa. This is more reasonable than the theory that the whole heaven is undergoing change just because of certain particular changes taking place around the earth.
Et quia praedicta positio, contra quam locutus est, in superficie rationabilis apparet, subiungit quod circa hoc immoratus est eius sermo plus quam dignum fuerit.	And because this theory against which he has spoken appears reasonable on the surface, he remarks that his discussion has lingered longer on this point than it deserves.

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Lecture 5
The saltness of the sea according to the opinions, of others

Chapter 3 cont.
περὶ δὲ τῆς ἁλμυρότητος, τοῖς μὲν ἅπαξ γεννήσασι καὶ ὅλως αὐτὴν γεννῶσιν ἀδύνατόν ἐστιν ἁλμυρὰν ποιεῖν. εἰ γὰρ παντὸς τοῦ ὑγροῦ τοῦ περὶ τὴν γῆν ὄντος καὶ ἀναχθέντος ὑπὸ τοῦ ἡλίου τὸ ὑπολειφθὲν ἐγένετο θάλαττα, εἴτ' ἐνυπῆρχε τοσοῦτος χυμὸς ἐν τῷ πολλῷ ὕδατι καὶ γλυκεῖ διὰ τὸ συμμειχθῆναί τινα γῆν τοιαύτην, οὐδὲν ἧττον ἐλθόντος πάλιν τοῦ διατμίσαντος ὕδατος ἀνάγκη, ἴσου γ' ὄντος τοῦ πλήθους, καὶ τὸ πρῶτον ἢ εἰ μηδὲ τὸ πρῶτον, μηδ' ὕστερον ἁλμυρὰν αὐτὴν εἶναι. εἰ δὲ καὶ τὸ πρῶτον εὐθὺς ἦν, λεκτέον τίς ἡ αἰτία, καὶ ἅμα διὰ τί οὐκ εἰ καὶ τότε ἀνήχθη καὶ νῦν πάσχει ταὐτό.	171 To return to the saltness of the sea: those who create the sea once for all, or indeed generate it at all, cannot account for its saltness. It makes no difference whether the sea is the residue of all the moisture that is about the earth and has been drawn up by the sun, or whether all the flavour existing in the whole mass of sweet water is due to the admixture of a certain kind of earth. Since the total volume of the sea is the same once the water that evaporated has returned, it follows that it must either have been salt at first too, or, if not at first, then not now either. If it was salt from the very beginning, then we want to know why that was so; and why, if salt water was drawn up then, that is not the case now.
ἀλλὰ μὴν καὶ ὅσοι τὴν γῆν αἰτιῶνται τῆς ἁλμυρότητος ἐμμειγνυμένην (ἔχειν γάρ φασι πολλοὺς χυμοὺς αὐτήν, ὥσθ' ὑπὸ τῶν ποταμῶν συγκαταφερομένην διὰ τὴν μεῖξιν ποιεῖν ἁλμυράν), ἄτοπον τὸ μὴ καὶ τοὺς ποταμοὺς ἁλμυροὺς εἶναι πῶς γὰρ δυνατὸν ἐν πολλῷ μὲν πλήθει ὕδατος ἐπίδηλον οὕτως ποιεῖν τὴν μεῖξιν τῆς τοιαύτης γῆς, ἐν ἑκάστῳ δὲ μή; δῆλον γὰρ ὅτι ἡ θάλαττά ἐστιν ἅπαν τὸ ποτάμιον ὕδωρ οὐδενὶ γὰρ διέφερεν ἀλλ' ἢ τῷ ἁλμυρὰ εἶναι τῶν ποταμῶν τοῦτο δ' ἐν ἐκείνοις ἔρχεται εἰς τὸν τόπον εἰς ὃν ἀθρόοι ῥέουσιν.	172 Again, if it is maintained that an admixture of earth makes the sea salt (for they say that earth has many flavours and is washed down by the rivers and so makes the sea salt by its admixture), it is strange that rivers should not be salt too. How can the admixture of this earth have such a striking effect in a great quantity of water and not in each river singly? For the sea, differing in nothing from rivers but in being salt, is evidently simply the totality of river water, and the rivers are the vehicle in which that earth is carried to their common destination.
ὁμοίως δὲ γελοῖον κἂν εἴ τις εἰπὼν ἱδρῶτα τῆς γῆς εἶναι τὴν θάλατταν οἴεταί τι σαφὲς εἰρηκέναι, καθάπερ Ἐμπεδοκλῆς πρὸς ποίησιν μὲν γὰρ οὕτως εἰπὼν ἴσως εἴρηκεν ἱκανῶς (ἡ γὰρ μεταφορὰ ποιητικόν), πρὸς δὲ τὸ γνῶναι τὴν φύσιν οὐχ ἱκανῶς οὐδὲ γὰρ ἐνταῦθα δῆλον πῶς ἐκ γλυκέος τοῦ πόματος ἁλμυρὸς γίγνεται ὁ ἱδρώς, πότερον ἀπελθόντος τινὸς μόνον οἷον τοῦ γλυκυτάτου, ἢ συμμειχθέντος τινός, καθάπερ ἐν τοῖς διὰ τῆς τέφρας ἠθουμένοις ὕδασιν. φαίνεται δὲ τὸ αἴτιον ταὐτὸ καὶ περὶ τὸ εἰς τὴν κύστιν περίττωμα συλλεγόμενον καὶ γὰρ ἐκεῖνο πικρὸν καὶ ἁλμυρὸν γίγνεται τοῦ πινομένου καὶ τοῦ ἐν τῇ τροφῇ ὑγροῦ (357b.) γλυκέος ὄντος. εἰ δὴ ὥσπερ τὸ διὰ τῆς κονίας ἠθούμενον ὕδωρ γίγνεται πικρόν, καὶ ταῦτα, τῷ μὲν οὔρῳ συγκαταφερομένης τοιαύτης τινὸς δυνάμεως οἵα καὶ φαίνεται ὑφισταμένη ἐν τοῖς ἀγγείοις ἁλμυρίς, τῷ δ' ἱδρῶτι συνεκκρινομένης ἐκ τῶν σαρκῶν, οἷον καταπλύνοντος τὸ τοιοῦτον ἐκ τοῦ σώματος τοῦ ἐξιόντος ὑγροῦ, δῆλον ὅτι κἀν τῇ θαλάττῃ τὸ ἐκ τῆς γῆς συγκαταμισγόμενον τῷ ὑγρῷ αἴτιον τῆς ἁλμυρότητος. ἐν μὲν οὖν τῷ σώματι γίγνεται τὸ τοιοῦτον ἡ τῆς τροφῆς ὑπόστασις διὰ τὴν ἀπεψίαν ἐν δὲ τῇ γῇ τίνα τρόπον ὑπῆρχε, λεκτέον.	173 It is equally absurd to suppose that anything has been explained by calling the sea 'the sweat of the earth', like Empedicles. Metaphors are poetical and so that expression of his may satisfy the requirements of a poem, but as a scientific theory it is unsatisfactory. Even in the case of the body it is a question how the sweet liquid drunk becomes salt sweat whether it is merely by the departure of some element in it which is sweetest, or by the admixture of something, as when water is strained through ashes. Actually the saltness seems to be due to the same cause as in the case of the residual liquid that gathers in the bladder. That, too, becomes bitter and salt though the liquid we drink and that contained in our food is sweet. If then the bitterness is due in these cases (as with the water strained through lye) to the presence of a certain sort of stuff that is carried along by the urine (as indeed we actually find a salt deposit settling in chamber-pots) and is secreted from the flesh in sweat (as if the departing moisture were washing the stuff out of the body), then no doubt the admixture of something earthy with the water is what makes the sea salt. Now in the body stuff of this kind, viz. the sediment of food, is due to failure to digest: but how there came to be any such thing in the earth requires explanation.
ὅλως δὲ πῶς οἷόν τε τοσοῦτον ὕδατος πλῆθος ξηραινομένης καὶ θερμαινομένης ἐκκριθῆναι;	174 Besides, how can the drying and warming of the earth cause the secretion such a great quantity of water; especially as that must be a mere fragment of what is left in the earth?
πολλοστὸν γὰρ δεῖ μέρος αὐτὸ τοῦ λειφθέντος εἶναι ἐν τῇ γῇ. ἔτι διὰ τί οὐ καὶ νῦν ὅταν ξηραινομένη τύχῃ γῆ, εἴτε πλείων εἴτε ἐλάττων, ἰδίει; (ἡ γὰρ ὑγρότης καὶ ὁ ἱδρὼς γίγνεται πικρός.) εἴπερ γὰρ καὶ τότε, καὶ νῦν ἐχρῆν. οὐ φαίνεται δὲ τοῦτο συμβαῖνον, ἀλλὰ ξηρὰ μὲν οὖσα ὑγραίνεται, ὑγρὰ δ' οὖσα οὐδὲν πάσχει τοιοῦτον. πῶς οὖν οἷόν τε περὶ τὴν πρώτην γένεσιν, ὑγρᾶς οὔσης τῆς γῆς, ἰδίειν ξηραινομένην; ἀλλὰ μᾶλλον εἰκός, ὥσπερ φασί τινες, ἀπελθόντος τοῦ πλείστου καὶ μετεωρισθέντος τοῦ ὑγροῦ διὰ τὸν ἥλιον, τὸ λειφθὲν εἶναι θάλατταν ὑγρὰν δ' οὖσαν ἰδίειν ἀδύνατον. τὰ μὲν οὖν λεγόμενα τῆς ἁλμυρότητος αἴτια διαφεύγειν φαίνεται τὸν λόγον	175 Again, waiving the question of quantity, why does not the earth sweat now when it happens to be in process of drying? If it did so then, it ought to do so now. But it does not: on the contrary, when it is dry it graws moist, but when it is moist it does not secrete anything at all. How then was it possible for the earth at the beginning when it was moist to sweat as it grew dry? Indeed, the theory that maintains that most of the moisture departed and was drawn up by the sun and that what was left over is the sea is more reasonable; but for the earth to sweat when it is moist is impossible.

Postquam philosophus determinavit de natura maris et eius generatione, nunc determinat de eius salsedine.	164. After determining about the nature of the sea and about its generation, the Philosopher now determines about its saltness.
Et primo inquirit de ea secundum opiniones aliorum; secundo ponit suam opinionem, ibi: nos autem dicamus et cetera.	First, he inquires about it according to the opinions of others; Secondly, he presents his own opinion (L. 6).
Circa primum, prosequitur de salsedine maris secundum tres opiniones philosophorum naturalium, in principio huius tractatus de mari positas.	With respect to the first he continues with the salt of the sea according to the three opinions of the natural philosophers presented in the beginning of this treatise on the sea.
Dicit ergo primo quod illi qui dixerunt quod mare semel generatum est, vel qualitercumque posuerunt ipsius generationem, non possunt assignare causam salsedinis. Dicunt enim isti quod a principio aqua circumdabat totam terram, et sol elevavit magnam partem aquae, ex quo contingit quod magna pars terrae remansit discooperta ab aquis; et illud quod fuit residuum et nondum desiccatum a sole, factum est mare. Si ergo in multitudine aquae maris, quae secundum naturam suam deberet esse dulcis, facta est causa salsedinis propter admixtionem alicuius terrae ad aquam quae remansit, quae potuit dulce convertere in tantam salsedinem; cum, redeunte per pluvias aqua quae evaporavit, necesse sit quod aequalis multitudo aquae conservetur supra terram, ut supra dictum est; necesse est quod etiam primo, antequam sol incoeperit desiccare, mare esset salsum; vel, si prius non fuit salsum, neque posterius salsum erit, ex quo tota aqua quae elevata est, redit. Et sic non potest dici quod terra admixta facit aquam existentem nunc minoris quantitatis salsam, quod non poterat facere salsam totam, cum sit aequalis quantitatis nunc et prius. Si autem etiam a principio mare erat salsum, remanebit assignare causam salsedinis. Et etiam dicendum est quare, si a principio non ferebatur sursum aqua per evaporationem, nunc hoc accidit.	165. He says therefore first [171] that those who declared that the sea was at onetime generated, or posit its generation in any way, cannot assign a reason for its saltness. For they say that in the beginning water surrounded the entire earth and that the sun raised aloft a great portion of the water, leaving a large area of the earth no longer covered with water, and that the residue, not yet dried up by the sun, became the sea. Now, if the cause of salt in the totality of the sea's water (which according to its nature ought to be sweet), came about because of earth's mixing with the water that remained, which was able to convert the sweet into so great saltness, then, since, with the return in the form of rain of the evaporated water, there necessarily results an equal amount of water's being preserved on earth, as was said, it is necessary that even in the first place, before the sun began its drying process, that the sea be salty; or if it was not salty before, it will not be salty later, because all the evaporated water returns. Consequently, it cannot be said that mixing with earth makes the water salty because now it exists in a smaller amount, while it could not make the total amount salty — since the amount both now and before is equal. But if the sea was salty from the start, it will remain to assign a cause of its saltness. Moreover, one should state why, if water was not borne aloft by evaporation from the very beginning, this happens now.
Deinde cum dicit: at vero et quicumque terram etc., prosequitur secundam opinionem. Et dicit quod illi etiam qui dixerunt admixtionem terrae esse causam salsedinis maris, non sufficienter ostendunt quare mare est salsum. Dicunt enim quod terra habet multos sapores secundum diversas sui partes; ita quod terra quam flumina deferunt ad mare, admiscetur mari, et facit ipsum salsum.	166. Then [172 he continues with the second opinion, and says that they who declared that mixing with earth to be the cause of the sea's saltness fail to explain sufficiently why the sea is salty. For they claim that the earth has many tastes according to its various areas, so that the earth which the rivers transport to the sea mingles with the sea and makes it salty.
Sed hoc inconveniens videtur, quod mare sic fiat salsum per admixtionem terrae, et fluvii non sint salsi, qui sunt minoris quantitatis. Si ergo magna multitudo aquae maris permutatur ad salsedinem ex admixtione terrae, multo magis immutaretur aqua uniuscuiusque fluvii. Manifestum est enim quod mare est congregatio omnium fluvialium aquarum: in nullo enim differt aqua maris ab aquis fluminum, nisi per salsedinem aquae; quae non accidit in aquis fluminum, sed solum in loco in quo omnia flumina congregantur. Et hoc non videtur possibile, si sola admixtio terrae a fluminibus delatae, salsedinem causaret.	But this seems unacceptable, namely, that the sea become salty through mixing with earth, while the rivers, which are smaller, are not salty. Indeed, if the vast quantity of the water of the sea is changed to salt by mixing with earth, the water of every river should, with even greater reason, be changed. For it is plain that the sea is an assemblage of all river waters — for the water of the sea differs from the water of rivers only by its saltness - something that does not occur in the waters of rivers, but only in the place where all the rivers come together. And this does not seem possible, if the sole mixing of-earth transported by the rivers were to be the cause of saltness.
Tertio ibi: similiter autem derisibile etc., improbat tertiam opinionem tribus rationibus. Quarum prima est sumpta ex hoc quod immanifeste causam salsedinis assignavit. Et dicit quod derisibile est, si quis putet aliquid planum dixisse, dicens mare esse sudorem terrae, et ob hoc esse salsum, sicut Empedocles dixit. Forte enim sufficienter dixit, si intendit metaphorice dicere, secundum modum poeticum: dicere enim aliquid per metaphoras pertinet ad poetas, et probabile est quod Empedocles, qui metrice scripsit, ut dicitur, multa metaphorice protulerit. Sed tamen sic aliquid dicere non sufficit ad cognoscendam naturam rei: quia res naturalis per similitudinem quae assumitur in metaphora, non est manifesta. Quomodo enim, cum illud quod homo potat, sit dulce, sudor exinde generatus fiet salsus? Non enim fit manifestum per metaphoram: utrum scilicet sudor remaneat salsus per separationem alicuius quod erat dulcissimum in poculo; aut efficiatur salsus per commixtionem alicuius, sicut accidit in aquis quae colantur per cinerem, quia per admixtionem cineris efficiuntur salsae vel amarae. Et eadem causa videtur esse de sapore urinae, quae est superfluitas collecta in vesica: quia huiusmodi superfluum fit amarum et salsum, cum humidum potatum sit dulce.	167. Thirdly [173], he disproves the third opinion with three arguments. The first of these is taken from the fact that it assigned a non-evident cause of the saltness. And he says that it is ridiculous for someone to think he is speaking plainly, when he says that the sea is the earth's sweat and is for that reason salty, as Empedocles said. This perhaps satisfies the demands of metaphorical utterances according to the manner of poets — for to speak in metaphors pertains to poets, and it is probable that Empedocles, who wrote in meter, so they say, uttered many things metaphorically. But such a manner of speaking is not sufficient for knowing the nature of a thing; because a natural thing is not revealed by the comparisons employed in a metaphor. For how does it come about that what a man drinks is sweet, whereas the sweat generated therefrom will be salty? The metaphor does not make it clear whether the sweat remains salty because of the separation of something that was very sweet in the drink, or by a mixing with something, as happens when water is strained through ashes, for by mixing with ashes it is made salty or bitter. And the same cause seems to be at work in the taste of urine, which is a superfluity collected in the bladder: for this residue becomes bitter and salty, although the moisture imbibed was sweet.
Si igitur ita est, quod aqua colata per calcem fit amara; et similiter etiam cum urina defertur aliqua res talis virtutis, quod possit ipsam salsam facere (nam in vasis in quibus residens conservatur urina, subsidere invenitur quaedam limositas salsa); et similiter est in sudore, quod adhaeret ei aliquid simile, cum sudor resolvitur a carnibus, quod facit ipsum salsum, tanquam si hoc humidum, quod exit a corpore per sudorem, abluat a carnibus illam superfluitatem quae facit sudorem salsum: si inquam ita est in istis tribus rebus, et metaphora de sudore est bene accepta, manifestum est quod etiam in mari erit causa salsedinis aliquid terrestre admixtum aquis. Quid autem sit quod facit salsedinem in corpore animalis, in sudore et urina, cognoscitur: quia est hypostasis alimenti, idest illud quod subsidet residuum ab eo quod attrahitur in usum alimenti nutriti. Et hoc quidem est causa salsedinis, quia non est digestum. Sed quid sit illud quod hoc modo possit facere salsedinem in mari, adhuc esset dicendum Empedocli, cum non sit manifestum. Et sic patet quod in hoc peccavit Empedocles, quod non manifeste assignavit causam.	Now, if it is true that water becomes bitter because it is strained through lime, and likewise if along with urine is carried something of such virtue as to make it salty (for when urine is kept standing in chamber-pots a certain salty sediment is found to settle); and likewise with sweat, something similar adheres to it when the sweat is exuded from the flesh, which makes it salty, as though the moisture leaving the body in the form of sweat washed from the flesh a residue which makes the sweat salty; if, I say, this is so in these three cases, and if the metaphor about sweat is rightly taken, then it is plain that also in the case of the sea, the cause of saltness will be something earthy mixing with the waters. But we know the cause of salt in the body of an animal, in sweat and in urine: it is the "hypostasis of food," i.e., the subsisting residue from what is appropriated as food by anything fed. The reason why it is salty is that it has not been digested. But what it is that can in like manner produce salt in the sea Empedocles has yet to say, since this is not manifest. And so it is plain that Empedocles sinned in this: that he did not clearly indicate the cause.
Secundam rationem ponit ibi: omnino autem quomodo possibile etc.: quia, desiccata et calefacta tanta multitudine aquae, quanta a mari segregatur, tamen tota aqua maris salsa remanet; pars autem quae elevatur a terra per evaporationem, est submultiplex illius aquae quae in terra relinquitur (dicitur autem submultiplex, quae comparatur ad aliud sicut dimidium ad duplum, vel sicut subtriplum ad triplum, et sic de aliis). Unde non videtur quod aqua maris, cum sit maior pars quam aqua elevata per evaporationem, ex hoc possit fieri salsa: nam sudor et urina, quae fiunt salsa, sunt multo minora quam humiditas in corpore remanens.	168. He presents the second argument [174]; namely, that in spite of the drying up and warming of such a vast amount of water as is taken from the sea, nevertheless the whole water of the sea still remains salty. Now the portion raised away from the earth by evaporation is a submultiple of the water left on the earth (that is called "submultiple" which is to another as 1/2 is to double, or 1/3 to triple, and so forth). Hence it does not seem that the water of the sea, since it is a greater amount than the water borne up by evaporation can become salty from this, for sweat and urine, both of which are salty, are much less in volume than the moisture remaining in the body.
Tertiam rationem ponit ibi: adhuc autem propter quid et cetera. Et dicit quod quaerendum est ab Empedocle quare nunc terra, postquam desiccata est a sole in aliqua parte sui, sive maiori sive minori, non sudat, ita quod sudor eius appareat amarus: si enim hoc fuit a principio, quod terra sudaret humorem amarum, et nunc deberet fieri. Sed hoc non videtur nunc accidere: videmus enim quod terra, cum est humida, siccari potest, et postquam est sicca, non patitur aliquid tale, scilicet ut sudet. Neque igitur possibile fuit quod in prima generatione mundi, terra existens humida, quia circumdata aquis, sudaret per exsiccationem: sed magis verisimilis est opinio illorum qui dixerunt quod mare non est sudor terrae, sed aqua relicta post exsiccationem alicuius partis terrae: quod enim terra humida existens sudet, videtur impossibile.	169. He presents the third argument [175], and says that Empedocles must be asked why it is that after being dried out in various small or large areas by the sun, the earth does not now sweat with a sweat that seems bitter: for if it was true in the beginning that the earth sweated a bitter moistness, it should be doing so even now. But this is not seen to be happening now: for we see that the earth, when moist, can be dried out, and after it is dried out, it does not undergo anything like this, i.e., sweating. Neither, therefore, was it possible in the primal generation of the world, when the earth was moist (because it was covered with water), for it to sweat through being dried out. Closer to the truth is the theory upheld by those who said that the sea is not the sweat of the earth but is water left after some portion of the earth did dry out. However, that the earth should sweat when moist, seems impossible.
Et sic ultimo concludit quod causae quae adducuntur de salsedine maris, videntur effugere rationem.	And so he finally concludes that the causes alleged for the saltness of the sea are seen to elude reason.

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Lecture 6
Cause of the sea's saltness according to Aristotle

Chapter 3 cont.
ἡμεῖς δὲ λέγωμεν ἀρχὴν λαβόντες τὴν αὐτὴν ἣν καὶ πρότερον ἐπειδὴ γὰρ κεῖται διπλῆν εἶναι τὴν ἀναθυμίασιν, τὴν μὲν ὑγρὰν τὴν δὲ ξηράν, δῆλον ὅτι ταύτην οἰητέον ἀρχὴν εἶναι τῶν τοιούτων. καὶ δὴ καὶ περὶ οὗ ἀπορῆσαι πρότερον ἀναγκαῖον, πότερον καὶ ἡ θάλαττα ἀεὶ διαμένει τῶν αὐτῶν οὖσα μορίων ἀριθμῷ ἢ τῷ εἴδει καὶ τῷ ποσῷ μεταβαλλόντων ἀεὶ τῶν μερῶν, καθάπερ ἀὴρ καὶ τὸ πότιμον ὕδωρ καὶ πῦρ (ἀεὶ γὰρ ἄλλο καὶ ἄλλο γίγνεται τούτων ἕκαστον, τὸ δ' εἶδος τοῦ πλήθους ἑκάστου τούτων μένει, καθάπερ τὸ τῶν ῥεόντων ὑδάτων καὶ τὸ τῆς φλογὸς ῥεῦμα) φανερὸν δὴ καὶ τοῦτο καὶ πιθανόν, ὡς ἀδύνατον μὴ τὸν αὐτὸν εἶναι περὶ πάντων τούτων λόγον, καὶ διαφέρειν ταχυτῆτι καὶ (358a.) βραδυτῆτι τῆς μεταβολῆς, ἐπὶ πάντων τε φθορὰν εἶναι καὶ γένεσιν, ταύτην μέντοι τεταγμένως συμβαίνειν πᾶσιν αὐτοῖς.	176 Since all the attempts to account for the saltness of the sea seem unsuccessful let us explain it by the help of the principle we have used already. Since we recognize two kinds of evaporation, one moist, the other dry, it is clear that the latter must be recognized as the source of phenomena like those we are concerned with. But there is a question which we must discuss first. Does the sea always remain numerically one and consisting of the same parts, or is it, too, one in form and volume while its parts are in continual change, like air and sweet water and fire? All of these are in a constant state of change, but the form and the quantity of each of them are fixed, just as they are in the case of a flowing river or a burning flame. The answer is clear, and there is no doubt that the same account holds good of all these things alike. They differ in that some of them change more rapidly or more slowly than others; and they all are involved in a process of perishing and becoming which yet affects them all in a regular course.
τούτων δ' οὕτως ἐχόντων, πειρατέον ἀποδοῦναι τὴν αἰτίαν καὶ περὶ τῆς ἁλμυρότητος. φανερὸν δὴ διὰ πολλῶν σημείων ὅτι γίγνεται τοιοῦτος ὁ χυμὸς διὰ σύμμειξίν τινος. ἔν τε γὰρ τοῖς σώμασι τὸ ἀπεπτότατον ἁλμυρὸν καὶ πικρόν, ὥσπερ καὶ πρότερον εἴπομεν ἀπεπτότατον γὰρ τὸ περίττωμα τῆς ὑγρᾶς τροφῆς τοιαύτη δὲ πᾶσα μὲν ἡ ὑπόστασις, μάλιστα δὲ ἡ εἰς τὴν κύστιν (σημεῖον δ' ὅτι λεπτοτάτη ἐστίν τὰ δὲ πεττόμενα πάντα συνίστασθαι πέφυκεν) ἔπειτα ἱδρώς [ἀεί] ἐν οἷς τὸ αὐτὸ σῶμα συνεκκρίνεται, ὃ ποιεῖ τὸν χυμὸν τοῦτον. ὁμοίως δὲ καὶ ἐν τοῖς καομένοις οὗ γὰρ ἂν μὴ κρατήσῃ τὸ θερμόν, ἐν μὲν τοῖς σώμασι γίγνεται περίττωσις, ἐν δὲ τοῖς καομένοις τέφρα.	177 This being so we must go on to try to explain why the sea is salt. There are many facts which make it clear that this taste is due to the admixture of something. First, in animal bodies what is least digested, the residue of liquid food, is salt and bitter, as we said before. All animal excreta are undigested, but especially that which gathers in the bladder (its extreme lightness proves this; for everything that is digested is condensed), and also sweat; in these then is excreted (along with other matter) an identical substance to which this flavour is due. The case of things burnt is analogous. What heat fails to assimilate becomes the excrementary residue in animal bodies, and, in things burnt, ashes.
διὸ καὶ τὴν θάλαττάν τινες ἐκ κατακεκαυμένης φασὶ γενέσθαι γῆς. ὃ οὕτω μὲν εἰπεῖν ἄτοπον, τὸ μέντοι ἐκ τοιαύτης ἀληθές ὥσπερ γὰρ καὶ ἐν τοῖς εἰρημένοις, οὕτω καὶ ἐν τῷ ὅλῳ ἔκ τε τῶν φυομένων καὶ γιγνομένων κατὰ φύσιν ἀεὶ δεῖ νοεῖν, ὥσπερ ἐκ πεπυρωμένων τὸ λειπόμενον τοιαύτην εἶναι γῆν, καὶ δὴ καὶ τὴν ἐν τῇ ξηρᾷ ἀναθυμίασιν πᾶσαν αὕτη γὰρ καὶ παρέχεται τὸ πολὺ τοῦτο πλῆθος. μεμειγμένης δ' οὔσης, ὥσπερ εἴπομεν, τῆς τε ἀτμιδώδους ἀναθυμιάσεως καὶ τῆς ξηρᾶς, ὅταν συνιστῆται εἰς νέφη καὶ ὕδωρ, ἀναγκαῖον ἐμπεριλαμβάνεσθαί τι πλῆθος ἀεὶ ταύτης τῆς δυνάμεως, καὶ συγκαταφέρεσθαι πάλιν ὕοντος, καὶ τοῦτ' ἀεὶ γίγνεσθαι κατά τινα τάξιν, ὡς ἐνδέχεται μετέχειν τὰ ἐνταῦθα τάξεως. ὅθεν μὲν οὖν ἡ γένεσις ἔνεστιν τοῦ ἁλμυροῦ ἐν τῷ ὕδατι, εἴρηται.	178 That is why some people say that it was burnt earth that made the sea salt. To say that it was burnt earth is absurd; but to say that it was something like burnt earth is true. We must suppose that just as in the cases we have described, so in the world as a whole, everything that grows and is naturally generated always leaves an undigested residue, like that of things burnt, consisting of this sort of earth. All the earthy stuff in the dry exhalation is of this nature, and it is the dry exhalation which accounts for its great quantity. Now since, as we have said, the moist and the dry evaporations are mixed, some quantity of this stuff must always be included in the clouds and the water that are formed by condensation, and must redescend to the earth in rain. This process must always go on with such regularity as the sublunary world admits of, and it is the answer to the question how the sea comes to be salt.
καὶ διὰ τοῦτο τά τε νότια ὕδατα πλατύτερα καὶ τὰ πρῶτα τῶν μετοπωρινῶν ὅ τε γὰρ νότος καὶ τῷ μεγέθει καὶ τῷ πνεύματι ἀλεεινότατος ἄνεμός ἐστιν, καὶ πνεῖ ἀπὸ τόπων ξηρῶν καὶ θερμῶν, ὥστε μετ' ὀλίγης ἀτμίδος. διὸ καὶ θερμός ἐστιν εἰ γὰρ καὶ μὴ τοιοῦτος, ἀλλ' ὅθεν ἄρχεται πνεῖν ψυχρός, οὐδὲν ἧττον προϊὼν διὰ τὸ συμπεριλαμβάνειν πολλὴν ἀναθυμίασιν ξηρὰν ἐκ τῶν σύνεγγυς τόπων θερμός ἐστιν ὁ δὲ βορέας ἅτε ἀφ' ὑγρῶν τόπων ἀτμιδώδης διὸ (358b.) ψυχρός τῷ δ' ἀπωθεῖν αἴθριος ἐνταῦθα, ἐν δὲ τοῖς ἐναντίοις ὑδατώδης. ὁμοίως δὲ καὶ ὁ νότος αἴθριος τοῖς περὶ τὴν Λιβύην. πολὺ οὖν ἐν τῷ καταφερομένῳ ὕδατι συμβάλλεται τοιοῦτον, καὶ τοῦ μετοπώρου πλατέα τὰ ὕδατα ἀνάγκη γὰρ τὰ βαρύτατα πρῶτα φέρεσθαι. ὥστ' ἐν ὅσοις ἔνεστι τῆς τοιαύτης γῆς πλῆθος, ῥέπει τάχιστα κάτω ταῦτα. καὶ θερμή γε ἡ θάλαττα διὰ τοῦτό ἐστιν πάντα γὰρ ὅσα πεπύρωται, ἔχει δυνάμει θερμότητα ἐν αὑτοῖς. ὁρᾶν δ' ἔξεστι καὶ τὴν κονίαν καὶ τὴν τέφραν καὶ τὴν ὑπόστασιν τῶν ζῴων καὶ τὴν ξηρὰν καὶ τὴν ὑγράν καὶ τῶν θερμοτάτων γε κατὰ τὴν κοιλίαν ζῴων συμβαίνει θερμοτάτην εἶναι τὴν ὑπόστασιν.	179 It also explains why rain that comes from the south, and the first rains of autumn, are brackish. The south is the warmest of winds and it blows from dry and hot regions. Hence it carries little moist vapour and that is why it is hot. (It makes no difference even if this is not its true character and it is originally a cold wind, for it becomes warm on its way by incorporating with itself a great quantity of dry evaporation from the places it passes over.) The north wind, on the other hand, coming from moist regions, is full of vapour and therefore cold. It is dry in our part of the world because it drives the clouds away before it, but in the south it is rainy; just as the south is a dry wind in Libya. So the south wind charges the rain that falls with a great quantity of this stuff. Autumn rain is brackish because the heaviest water must fall first; so that that which contains the greatest quantity of this kind of earth descends quickest. This, too, is why the sea is warm. Everything that has been exposed to fire contains heat potentially, as we see in the case of lye and ashes and the dry and liquid excreta of animals. Indeed those animals which are hottest in the belly have the hottest excreta.
γίγνεται μὲν οὖν ἀεί τε πλατυτέρα διὰ ταύτην τὴν αἰτίαν, ἀνάγεται δ' ἀεί τι μέρος αὐτῆς μετὰ τοῦ γλυκέος (ἀλλ' ἔλαττον τοσούτῳ ὅσῳ καὶ ἐν τῷ ὑομένῳ τὸ ἁλμυρὸν καὶ πλατὺ τοῦ γλυκέος ἔλαττον διόπερ ἰσάζει ὡς ἐπίπαν εἰπεῖν).	180 The action of this cause is continually making the sea more salt, but some part of its saltness is always being drawn up with the sweet water. This is less than the sweet water in the same ratio in which the salt and brackish element in rain is less than the sweet, and so the saltness of the sea remains constant on the whole.
ὅτι δὲ γίγνεται ἀτμίζουσα πότιμος καὶ οὐκ εἰς θάλατταν συγκρίνεται τὸ ἀτμίζον, ὅταν συνιστῆται πάλιν, πεπειραμένοι λέγωμεν. πάσχει δὲ καὶ τἆλλα ταὐτό καὶ γὰρ οἶνος καὶ πάντες οἱ χυμοί, ὅσοι ἂν ἀτμίσαντες πάλιν εἰς ὑγρὸν συστῶσιν, ὕδωρ γίγνονται πάθη γὰρ τἆλλα διά τινα σύμμειξιν τοῦ ὕδατός ἐστιν, καὶ οἷον ἄν τι ᾖ τὸ συμμειχθέν, τοιοῦτον ποιεῖ τὸν χυμόν. ἀλλὰ περὶ μὲν τούτων ἐν ἄλλοις καιροῖς οἰκειοτέροις ποιητέον τὴν σκέψιν.	181 Salt water when it turns into vapour becomes sweet, and the vapour does not form salt water when it condenses again. This I know by experiment. The same thing is true in every case of the kind: wine and all fluids that evaporate and condense back into a liquid state become water. They all are water modified by a certain admixture, the nature of which determines their flavour. But this subject must be considered on another more suitable occasion.
νῦν δὲ τοσοῦτον λέγωμεν, ὅτι τῆς θαλάττης ὑπαρχούσης αἰεί τι ἀνάγεται καὶ γίγνεται πότιμον καὶ ἄνωθεν ἐν τῷ ὑομένῳ κατέρχεται ἄλλο γεγενημένον, οὐ τὸ ἀναχθέν καὶ διὰ βάρος ὑφίσταται τῷ ποτίμῳ. καὶ διὰ τοῦτο οὔτ' ἐπιλείπει, ὥσπερ οἱ ποταμοί, ἀλλ' ἢ τοῖς τόποις (τοῦτο δ' ἐπ' ἀμφοτέρων ἀνάγκη συμβαίνειν ὁμοίως), οὔτε ἀεὶ τὰ αὐτὰ μέρη διαμένει, οὔτε γῆς οὔτε θαλάττης, ἀλλ' ἢ μόνον ὁ πᾶς ὄγκος. καὶ γὰρ καὶ περὶ γῆς ὁμοίως δεῖ ὑπολαβεῖν τὸ μὲν γὰρ ἀνέρχεται, τὸ δὲ πάλιν συγκαταβαίνει, καὶ τοὺς τόπους μεταβάλλει τά τ' ἐπιπολάζοντα καὶ τὰ κατιόντα πάλιν.	182 For the present let us say this. The sea is there and some of it is continually being drawn up and becoming sweet; this returns from above with the rain. But it is now different from what it was when it was drawn up, and its weight makes it sink below the sweet water. This process prevents the sea, as it does rivers, from drying up except from local causes (this must happen to sea and rivers alike). On the other hand the parts neither of the earth nor of the sea remain constant but only their whole bulk. For the same thing is true of the earth as of the sea: some of it is carried up and some comes down with the rain, and both that which remains on the surface and that which comes down again change their situations.
ὅτι δ' ἐστὶν ἐν μείξει τινὸς τὸ ἁλμυρόν, δῆλον οὐ μόνον ἐκ τῶν εἰρημένων, ἀλλὰ καὶ ἐάν τις ἀγγεῖον (359a.) πλάσας θῇ κήρινον εἰς τὴν θάλατταν, περιδήσας τὸ στόμα τοιούτοις ὥστε μὴ παρεγχεῖσθαι τῆς θαλάττης τὸ γὰρ εἰσιὸν διὰ τῶν τοίχων τῶν κηρίνων γίγνεται πότιμον ὕδωρ ὥσπερ γὰρ δι' ἠθμοῦ τὸ γεῶδες ἀποκρίνεται καὶ τὸ ποιοῦν τὴν ἁλμυρότητα διὰ τὴν σύμμειξιν. τοῦτο γὰρ αἴτιον καὶ τοῦ βάρους (πλέον γὰρ ἕλκει τὸ ἁλμυρὸν ἢ τὸ πότιμον) καὶ τοῦ πάχους καὶ γὰρ τὸ πάχος διαφέρει τοσοῦτον ὥστε τὰ πλοῖα ἀπὸ τοῦ αὐτοῦ τῶν ἀγωγίμων βάρους ἐν μὲν τοῖς ποταμοῖς ὀλίγου καταδύνειν, ἐν δὲ τῇ θαλάττῃ μετρίως ἔχειν καὶ πλευστικῶς διόπερ ἔνιοι τῶν ἐν τοῖς ποταμοῖς γεμιζόντων διὰ ταύτην τὴν ἄγνοιαν ἐζημιώθησαν. τεκμήριον δὲ τοῦ μειγνυμένου τὸ παχύτερον εἶναι τὸν ὄγκον ἐὰν γάρ τις ὕδωρ ἁλμυρὸν ποιήσῃ σφόδρα μείξας ἅλας, ἐπιπλέουσι τὰ ᾠά, κἂν ᾖ πλήρη σχεδὸν γὰρ ὥσπερ πηλὸς γίγνεται τοσοῦτον ἔχει σωματῶδες πλῆθος ἡ θάλαττα. ταὐτὸ δὲ τοῦτο δρῶσι καὶ περὶ τὰς ταριχείας. εἰ δ' ἔστιν ὥσπερ μυθολογοῦσί τινες ἐν Παλαιστίνῃ τοιαύτη λίμνη, εἰς ἣν ἐάν τις ἐμβάλῃ συνδήσας ἄνθρωπον ἢ ὑποζύγιον ἐπιπλεῖν καὶ οὐ καταδύεσθαι κατὰ τοῦ ὕδατος, μαρτύριον ἂν εἴη τι τοῖς εἰρημένοις λέγουσι γὰρ πικρὰν οὕτως εἶναι τὴν λίμνην καὶ ἁλμυρὰν ὥστε μηδένα ἰχθὺν ἐγγίγνεσθαι, τὰ δὲ ἱμάτια ῥύπτειν, ἐάν τις διασείσῃ βρέξας. ἔστι δὲ καὶ τὰ τοιαῦτα σημεῖα πάντα τῶν εἰρημένων, ὅτι τὸ ἁλμυρὸν ποιεῖ σῶμά τι, καὶ γεῶδές ἐστιν τὸ ἐνυπάρχον ἔν τε γὰρ τῇ Χαονίᾳ κρήνη τίς ἐστιν ὕδατος πλατυτέρου, ἀπορρεῖ δ' αὕτη εἰς ποταμὸν πλησίον γλυκὺν μέν, ἰχθῦς δ' οὐκ ἔχοντα εἵλοντο γὰρ δή, ὡς οἱ ἐκεῖ μυθολογοῦσιν, ἐξουσίας δοθείσης ὑπὸ τοῦ Ἡρακλέους, ὅτ' ἦλθεν ἄγων ἐκ τῆς Ἐρυθείας τὰς βοῦς, ἅλας ἀντὶ τῶν ἰχθύων, οἳ γίγνονται αὐτοῖς ἐκ τῆς κρήνης τούτου γὰρ τοῦ ὕδατος ἀφέψοντές τι μέρος τιθέασι, καὶ γίγνεται ψυχθέν, ὅταν ἀπατμίσῃ τὸ ὑγρὸν ἅμα τῷ θερμῷ, ἅλες, οὐ χονδροὶ ἀλλὰ χαῦνοι καὶ λεπτοὶ ὥσπερ χιών. εἰσίν τε τήν τε δύναμιν ἀσθενέστεροι τῶν ἄλλων καὶ πλείους ἡδύνουσιν ἐμβληθέντες, καὶ τὴν χροιὰν οὐχ ὁμοίως λευκοί. τοιοῦτον δ' ἕτερον γίγνεται καὶ ἐν Ὀμβρικοῖς (359b.) ἔστι γάρ τις τόπος ἐν ᾧ πεφύκασι κάλαμοι καὶ σχοῖνος τούτων κατακάουσι, καὶ τὴν τέφραν ἐμβάλλοντες εἰς ὕδωρ ἀφέψουσιν ὅταν δὲ λίπωσί τι μέρος τοῦ ὕδατος, τοῦτο ψυχθὲν ἁλῶν γίγνεται πλῆθος. ὅσα δ' ἐστὶν ἁλμυρὰ ῥεύματα ποταμῶν ἢ κρηνῶν, τὰ πλεῖστα θερμά ποτε εἶναι δεῖ νομίζειν, εἶτα τὴν μὲν ἀρχὴν ἀπεσβέσθαι τοῦ πυρός, δι' ἧς δὲ διηθοῦνται γῆς, ἔτι μένειν οὖσαν οἷον κονίαν καὶ τέφραν. εἰσὶ δὲ πολλαχοῦ καὶ κρῆναι καὶ ῥεύματα ποταμῶν παντοδαποὺς ἔχοντα χυμούς, ὧν πάντων αἰτιατέον τὴν ἐνοῦσαν ἢ ἐγγιγνομένην δύναμιν πυρός καομένη γὰρ ἡ γῆ τῷ μᾶλλον καὶ ἧττον παντοδαπὰς λαμβάνει μορφὰς καὶ χρόας χυμῶν στυπτηρίας γὰρ καὶ κονίας καὶ τῶν ἄλλων τῶν τοιούτων γίγνεται πλήρης δυνάμεων, δι' ὧν τὰ ἠθούμενα ὕδατα ὄντα γλυκέα μεταβάλλει, καὶ τὰ μὲν ὀξέα γίγνεται, καθάπερ ἐν τῇ Σικάνῃ τῆς Σικελίας ἐκεῖ γὰρ ὀξάλμη γίγνεται, καὶ χρῶνται καθάπερ ὄξει πρὸς ἔνια τῶν ἐδεσμάτων αὐτῷ. ἔστι δὲ καὶ περὶ Λύγκον κρήνη τις ὕδατος ὀξέος, περὶ δὲ τὴν Σκυθικὴν πικρά τὸ δ' ἀπορρέον αὐτῆς τὸν ποταμὸν εἰς ὃν εἰσβάλλει ποιεῖ πικρὸν ὅλον. αἱ δὲ διαφοραὶ τούτων ἐκεῖθεν δῆλαι, ποῖοι χυμοὶ ἐκ ποίων γίγνονται κράσεων εἴρηται δὲ περὶ αὐτῶν χωρὶς ἐν ἄλλοις.	183 There is more evidence to prove that saltness is due to the admixture of some substance, besides that which we have adduced. Make a vessel of wax and put it in the sea, fastening its mouth in such a way as to prevent any water getting in. Then the water that percolates through the wax sides of the vessel is sweet, the earthy stuff, the admixture of which makes the water salt, being separated off as it were by a filter. It is this stuff which make salt water heavy (it weighs more than fresh water) and thick. The difference in consistency is such that ships with the same cargo very nearly sink in a river when they are quite fit to navigate in the sea. This circumstance has before now caused loss to shippers freighting their ships in a river. That the thicker consistency is due to an admixture of something is proved by the fact that if you make strong brine by the admixture of salt, eggs, even when they are full, float in it. It almost becomes like mud; such a quantity of earthy matter is there in the sea. The same thing is done in salting fish. Again if, as is fabled, there is a lake in Palestine, such that if you bind a man or beast and throw it in it floats and does not sink, this would bear out what we have said. They say that this lake is so bitter and salt that no fish live in it and that if you soak clothes in it and shake them it cleans them. The following facts all of them support our theory that it is some earthy stuff in the water which makes it salt. In Chaonia there is a spring of brackish water that flows into a neighbouring river which is sweet but contains no fish. The local story is that when Heracles came from Erytheia driving the oxen and gave the inhabitants the choice, they chose salt in preference to fish. They get the salt from the spring. They boil off some of the water and let the rest stand; when it has cooled and the heat and moisture have evaporated together it gives them salt, not in lumps but loose and light like snow. It is weaker than ordinary salt and added freely gives a sweet taste, and it is not as white as salt generally is. Another instance of this is found in Umbria. There is a place there where reeds and rushes grow. They burn some of these, put the ashes into water and boil it off. When a little water is left and has cooled it gives a quantity of salt. Most salt rivers and springs must once have been hot. Then the original fire in them was extinguished but the earth through which they percolate preserves the character of lye or ashes. Springs and rivers with all kinds of flavours are found in many places. These flavours must in every case be due to the fire that is or was in them, for if you expose earth to different degrees of heat it assumes various kinds and shades of flavour. It becomes full of alum and lye and other things of the kind, and the fresh water percolates through these and changes its character. Sometimes it becomes acid as in Sicania, a part of Sicily. There they get a salt and acid water which they use as vinegar to season some of their dishes. In the neighbourhood of Lyncus, too, there is a spring of acid water, and in Scythia a bitter spring. The water from this makes the whole of the river into which it flows bitter. These differences are explained by a knowledge of the particular mixtures that determine different savours. But these have been explained in another treatise.
περὶ μὲν οὖν ὕδατος καὶ θαλάττης, δι' ἃς αἰτίας αἰεί τε συνεχῶς εἰσι καὶ πῶς μεταβάλλουσι καὶ τίς ἡ φύσις αὐτῶν, ἔτι δ' ὅσα πάθη κατὰ φύσιν αὐτοῖς συμβαίνει ποιεῖν ἢ πάσχειν, εἴρηται σχεδὸν ἡμῖν περὶ τῶν πλείστων.	184 We have now given an account of waters and the sea, why they persist, how they change, what their nature is, and have explained most of their natural operations and affections.

Reprobatis opinionibus de salsedine maris, hic ponit opinionem propriam. Et circa hoc tria facit:	170. Having rejected these theories about the salt of the sea, he now presents his own opinion. About this he does three things:
primo praemittit quaedam quae sunt necessaria ad propositum manifestandum; secundo assignat causam salsedinis maris, ibi: his autem sic se habentibus etc.; tertio manifestat quod dixerat per signa, ibi: quod autem est in commixtione et cetera.	First, he prefaces some things needed for manifesting the proposition; Secondly, he assigns the cause of the sea's saltness, at 171; Thirdly, he manifests what he had said through signs, at 177.
Circa primum duo facit. Quorum primum resumit ex praedictis, videlicet quod est duplex exhalatio, una humida et alia sicca: et hanc putandum est esse principium horum, scilicet salsedinis maris.	In regard to the first he does two things [176]. The first item he repeats from the foregoing is that exhalations are of two kinds: one is moist and the other dry; and this must be regarded as the source of these, i.e., of the sea's saltness.
Secundum est, quod movet dubitationem, de qua oportet primo videre veritatem, antequam propositum manifestet. Et est ista quaestio: utrum partes maris semper maneant eaedem numero; aut permutentur secundum numerum, et maneant eaedem secundum quantitatem, sicut accidit in aere et in aqua potabili fluminum et in igne. In his enim omnibus partes fiunt aliae et aliae numero, sed species vel forma multitudinis harum partium manet eadem: et hoc apparet maxime in aquis fluentibus et in fluxu flammae, quae per successionem fumi semper innovatur, ut supra dictum est, et tamen flamma semper manet eadem in numero. Unde probabile est non esse eandem rationem in his omnibus: nam ad minus differentia est secundum velocitatem permutationis; manifestum est enim quod citius permutantur partes aquae fluentis, quam partes terrae. In omnibus tamen est generatio et corruptio secundum partes per aliquem ordinem.	Secondly, he raises a problem whose true solution must be seen before the proposition is manifested. The problem is this: do the parts of the sea always remain numerically the same or are they changed in number while remaining the same according to quantity, as happens in air and in the drinkable water of rivers and in fire? For in all these the parts become other and other in number, but the species or form of the aggregate of these parts remains the same; and this is especially evident in flowing waters and in a burning flame, which is forever being renewed by successively new fumes, as was said above, and yet the flame always remains the same numerical one. Hence it is probable that all these cases are not exactly the same, for there is at least a difference so far as the rapidity of change is concerned: for it is plain that the parts of a flowing stream are exchanged more rapidly than the parts of the earth. Yet in all these cases there is a generation and corruption according to parts, following a certain order.
Deinde cum dicit: his autem sic se habentibus etc., assignat causam salsedinis maris. Et circa hoc duo facit:	171. Then [177] he assigns the cause of the sea's salt. About this he does two things:
primo ostendit in generali unde causetur sapor salsus; secundo unde causetur salsedo in mari, ibi: propter quod et mare et cetera.	First, he shows in general from what source a salty savor is produced; Secondly, from what source is derived the saltness of the sea, at 172.
Dicit ergo primo quod, cum praemissa sic se habeant ut dictum est, oportet reddere causam de salsedine maris. Manifestum est autem per multa signa quod sapor salsus causatur ex admixtione alicuius. Videmus enim quod in corporibus animalium illud quod est indigestissimum, est salsum et amarum: hoc autem maxime est superfluitas alimenti, et maxime quae congregatur in vesica. Et quod haec sit indigestissima, significatur per hoc quod est subtilissima inter omnes superfluitates; omnia autem digesta videntur inspissata esse a calore. Et sicut est de urina, ita est de sudore: similiter enim cum sudore segregatur aliquid indigestum, quod facit talem saporem. Similiter est in adustis: quia illud quod est residuum ab actione caloris, inquantum calor non potest vincere, in corporibus animalium fit superfluitas, in adustis autem fit cinis, per cuius admixtionem aqua etiam redditur salsa et amara.	He says therefore first [177] that, since the above are as described, there is need to set forth the cause of the sea's saltness. For it is plain by many signs that the salty taste is caused by an admixture of something. For we see that, in the bodies of animals, what is most undigested is salty and bitter: this is especially the residue of food, and more especially the residue collected in the bladder. That this is least digested is indicated by the fact that it is the most refined of all the residues, whereas all digested things are seen to be thickened by heat. And as with urine, so with sweat: for likewise with sweat, something undigested is separated which gives it this taste. So too with burnt things: because whatever is left after the action of the heat, that the heat cannot overcome, becomes a residue in the bodies of animals, and ash in burned objects, which, if mixed with water, makes it salty and bitter.
Deinde cum dicit: propter quod et mare etc., assignat specialiter causam salsedinis maris. Et circa hoc tria facit:	172. Then [178] he assigns the specific cause of the sea's saltness. About this he does three things:
primo facit quod dictum est; secundo hoc manifestat per quaedam signa, ibi: et propter hoc Australes etc.; tertio excludit quasdam obiectiones, ibi: fit igitur semper alterum et cetera.	First, he does what is said; Secondly, he manifests this through certain signs, at 173; Thirdly, he excludes some objections, at 174.
Dicit ergo primo, quod propter hoc quod sapor salsus et amarus invenitur causari ex admixtione alicuius indigesti vel adusti, quidam dixerunt quod mare erat factum ex terra adusta. Quod quidem inconveniens est, si intelligatur secundum quod dicitur: sed si intelligatur dictum per similitudinem, ut scilicet salsedo in mari causetur per admixtionem alicuius quod est simile cum terra adusta, sic verum est. Sicut enim contingit in praedictis, scilicet urina, sudore et cinere, sic oportet intelligere et in tota terra: sicuti enim ex ignitis relinquitur aliquid quod non potuit ignis dissolvere, ita oportet intelligere relinqui circa terram ab actione caloris aliquid simile cineri relicto ab actione ignis. Et huius similitudinem habet exhalatio quae fit ex arida, cuius multitudinem terra exhibet. Huiusmodi igitur exhalatio sicca cum admiscetur vaporosae exhalationi, quae condensatur in nubes et pluviam, necesse est quod semper in illa exhalatione humida contineatur aliquid virtutis huius, scilicet exhalationis siccae; et sic simul utrumque commixtum fertur deorsum, aqua pluente. Hoc autem fit secundum quendam ordinem semper, ut scilicet exhalationes commixtae eleventur, et iterum cadant per pluviam. Dico autem hoc secundum ordinem fieri, secundum quod ea quae hic inferius fiunt, possunt participare ordinem: non enim sic pure participant ordinem ut sint semper eodem modo, sicut est de corporibus caelestibus, sed accidunt ut frequenter. Et sic concludit quod dictum est unde fiat generatio salsi in aqua maris.	He says therefore first [178] that since a salty and bitter taste is found to be caused by the admixture of something undigested or burnt, some have said that the sea was formed out of charred earth. But this is unacceptable if taken in a literal sense; taken as a metaphor, however, namely, in the sense that the saltiness in the sea is caused by a mixing with something akin to charred earth, then it is true. For just as it occurs in the aforesaid, namely, in urine, sweat and ashes, so it must be understood even in regard to the earth as a whole: just as burning objects leave a residue of certain items that the fire was unable to dissolve, so too we must understand something to be left with respect to the earth by the action of heat, similar to the ash left by the action of fire. An example of this is the exhalation arising out of dry land, the magnitude of which the earth shows. Now when a dry exhalation of this sort mixes with the moist exhalation that is condensed into clouds and rain, it is necessary that in that moist exhalation there be contained something of the power of that dry exhalation; as a consequence, both mixed together re-descend when it rains. But this always occurs in a definite order: the mingled exhalations are borne aloft and re-descend in the form of rain. I say that this takes place in a definite order, i.e., to the extent that things occurring in the lower regions can participate in order: for they do not participate in order so perfectly as to occur always in the same way as do the heavenly bodies, but so as to occur for the most part. And thus he concludes that this sets forth whence there is generation of salt in the water of the sea.
Deinde cum dicit: et propter hoc Australes etc., manifestat quae dixerat per quaedam signa. Et dicit quod propter hoc quod exhalatio sicca admiscetur evaporationi humidae, aquae Australes et aquae quae primo cadunt in autumno, sunt latiores, idest graviores et magis ad salsedinem tendentes.	173. Then [179] he manifests what he had said through certain signs. And he says that because the dry exhalation mixes with the moist evaporation, southern waters and the first waters to fall in autumn are brackish, i.e., heaver and more on the salty side.
Et primo manifestat hoc de aquis Australibus, idest quae cadunt Austro flante. Auster enim et flatu et magnitudine est valde calidus: flat enim a locis calidis et siccis, in quibus est parum de vapore humido, et ideo est calidus. Sed quia posset aliquis dicere quod flat a locis frigidis, scilicet a polo Antarctico, quem oportet esse frigidum propter distantiam a sole, ideo subiungit quod, etsi hoc dicatur quod non flat a locis calidis sed a frigidis, tamen oportet quod transeat ad nos per loca calida et sicca, ex locis propinquis; et ideo est calidus. Sed Boreas, qui venit ad nos immediate ex locis frigidis, congregat multos vapores humidos et frigidos; et propter hoc est frigidus. Sed tamen nobis est serenus, quia impellit huiusmodi vapores ad partem oppositam: sed in locis et regionibus meridionalibus est aquosus, quia illuc impellit vapores. Et e converso Auster est serenus illis qui habitant in meridionalibus, scilicet circa Lybiam, cum nobis sit pluviosus. Sic igitur quia Auster colligit multum de exhalatione sicca, talis ventus confert multum ad hoc quod descendat aqua salsa. Et sic patet ratio unius eorum quae dicta sunt, scilicet quare aquae Australes sunt latiores.	First he explains this with respect to "southern" waters, i.e., which fall with the south wind blowing. For the south wind in its blowing and in its size is very warm: for it blows from regions that are hot and dry and have little moisture — that is why it is a hot wind. But because one could say that it blows from a cold region, namely, from the antarctic pole, which must be cold on account of its distance from the sun, he adds that, even supposing that it blows, not from the hot, but from the cold places, nevertheless it must travel toward us through regions close to us that are hot and dry, as to proximate regions: hence it is hot. But the north wind, which comes to us directly from cold regions, collects many moist and cold vapors along with it: therefore, it is a cold wind. Yet for us it brings clear weather, because it drives these vapors in the opposite direction; but in places and regions in the south it is a wet wind, because that is where it drives the vapors. Conversely, a south wind is clear for those who live in the south, namely, around Libya, but for us it is rainy. And so, because a south wind collects a large quantity of dry exhalation, such a wind contributes a great deal to the falling of water that is salty. Thus is made plain the reason for one of the statements, namely, why rains from the south are brackish.
Sed quia hoc etiam dixerat de primis aquis autumnalibus, assignat etiam huius causam: quia scilicet necesse est quod ea quae sunt gravissima in vaporibus elevatis, prius deorsum ferantur; gravissima autem sunt in quibus est plurimum de terrestri; et ideo aquae primo cadentes in autumno post aestatem, sunt latiores, valde plurimum de terrestri habentes.	But because the same was said of the first rains of autumn, he also assign s a cause for this: it is necessary that the heaviest constituents of the vapors carried aloft descend first; but the heaviest are those containing the most earth; and that is why the first waters to fall in autumn after the summer are brackish and have a great deal of what is earthy.
Aliud etiam signum assignat praedictae rationi assignatae de salsedinis causa: quia scilicet propter hoc mare est calidum, et regiones propinquae mari sunt calidiores, propter abundantiam scilicet praedictae exhalationis mixtae aquae maris. Quaecumque enim fuerint ignita, etiam post extinctionem videntur habere virtutem caloris in seipsis, ut patet in cinere et calce et superfluitate animalium habentium calidos ventres. Et huius ratio est, quia in huiusmodi manet virtus caloris alterantis cum exhalatione sicca. Unde, cum exhalationem siccam resolutam a terra desiccata, dixerit esse causam salsedinis maris, consequens est ut etiam in mari caliditas ex hoc abundet.	He gives another sign in support of the reason assigned as the cause of saltness, namely, that the reason why the sea is warm and the regions near the sea are comparatively warmer is due to the abundance of the above-mentioned exhalation mixed with the water of the sea. For things previously afire are seen to possess within themselves the virtue of heat even after the fire has gone out: this is plain in ashes and lime and the excrement of warm-bellied animals. The reason for this is that the virtue of the alterating heat remains in them along with the dry exhalation. Hence, since he had said that the cause of the saltness of the sea was the dry exhalation resolved from dried-out earth, it follows that the sea will also derive an abundance of warmth therefrom.
Deinde cum dicit: fit igitur semper alterum etc., excludit quasdam dubitationes circa praedicta. Et circa hoc duo facit:	174. Then at [180] he excludes some doubts on the aforesaid. About this he does two things:
primo excludit dubitationes; secundo concludit ex praemissis causam salsedinis maris, ibi: nunc autem tantum et cetera.	First, he excludes the doubts; Secondly, from what has gone before he concludes to the cause of the saltiness of the sea, at 176.
Prima dividitur in duas, secundum duas dubitationes quas solvit. Est autem prima dubitatio: cum aqua maris non continue maneat eadem numero secundum partes, sed evaporet et iterum cadat, non videtur esse causa salsedinis maris exhalatio sicca admixta, sed magis evaporatio ab aqua salsa.	The first is divided into two parts according to the two doubts solved; [The second one is solved at 175.] The first doubt [180] is that since the water of the sea does not continue to have numerically the same parts but evaporates and re-descends, it does not seem that the cause of the saltness of the sea is the mixed-in dry exhalation, but rather an evaporation from salt water.
Et ad hanc dubitationem tollendam, dicit quod aqua maris semper fit altera et altera secundum partes, et quaelibet pars habet in sui generatione praedictam causam salsedinis, idest admixtionem terrestris exhalationis. Verum est etiam quod semper aliqua pars aquae salsae elevatur per evaporationem cum dulci: sed cum citius evaporet subtile quam grossum, et dulce est subtilius quam salsum, oportet quod minus de salso elevetur quam de dulci; sed per admixtionem exhalationis siccae, illud dulce accrescit iterum in salsedinem; et sic mare semper conservatur aequale et in quantitate et in salsedine. Et hoc ut ad totum, idest per comparationem ad totum mare, conservatur aequale vel quasi aequale: non enim semper punctalis conservatur praedicta quantitas.	To remove this doubt he says that the water of the sea is forever becoming other and other as to its parts, and each part has in its generation the aforesaid cause of saltness, namely, the admixture of the earthy exhalation. Now it is also true that some part of the salt water is always being borne aloft with the sweet through evaporation — but since something refined evaporates more quickly than something dense, and the sweet is more refined than the salty, necessarily less of the salty than of the sweet is elevated; but through being mixed with the dry exhalation the sweet again grows in saltness, and thus the sea is forever maintained constant both in quantity and in salt. And this is said of the sea "as a whole," i.e., so far as the whole sea is concerned, it is kept constant or practically so — for the aforesaid quantity is not always kept absolutely exactly.
Secundam dubitationem solvit ibi: quod autem fit vaporans et cetera. Et est haec dubitatio: cum aqua maris sit salsa, unde contingit quod e vaporibus resolutis ab aqua maris generatur aqua dulcis?	175. The solution of the second doubt is at [181]. The doubt is this: since the water of the sea is salty, what accounts for the fact that sweet water is generated from the vapors resolved from the waters of the sea?
Et ad hoc solvendum dicit: iterum dicendum est quod illud quod evaporat in mari, quando condensatur, fit aqua potabilis et dulcis; et ideo non convertitur in mare, idest in aquam salsam, sed in aquam simpliciter. Et hoc idem patiuntur alia; sicut vinum et omnes humores, cum condensantur, convertuntur in aquam simpliciter; cum enim evaporant, vapores illi condensati convertuntur in aquam. Et huius ratio est, quia principium omnium humorum est aqua; resolvuntur autem omnia in sua principia. Omnia autem alia humida generantur ex aqua per aliquam passionem vel alterationem; quae passiones variantur propter admixtionem, et fit sapor eius secundum conditionem eius quod miscetur. Et propter hoc in generatione variatur aqua, et fit salsa. Sed quia unumquodque resolvitur in suum principium simpliciter, ut dictum est, consequens est ut tam ex aqua maris salsa, quam ex omnibus humoribus, cuiuscumque sint vaporis, per evaporationem generetur aqua simpliciter.	To answer this he says that we must repeat that what evaporates in the sea becomes, when it is condensed, drinkable and sweet; therefore, it is not converted back into "sea," i.e., into salt water, but into fresh water. This happens to other things: wine and all liquids, when they are condensed, are turned into simple water: for when they evaporate, their condensed vapors are turned into water. The reason for this is that the principle of all moisture is water, and all things are resolved into their principles. Now all other liquids are generated from water which is affected or altered in some way, which affections vary according to the ingredients, and the savor depends on what is mixed in. This explains why, in the process of being generated, water varies and becomes salty. But because each thing is resolved into its principle absolutely, as has been said, the consequence is that whether it is salty sea water, or any liquid whatsoever of any vapor [savor?] you wish, the product of evaporation is simple water.
Deinde cum dicit: nunc autem tantum etc., ex omnibus praemissis colligit causam de salsedine maris. Et dicit quod nunc dicendum est quod semper aliqua pars aquae maris sursum ducitur per evaporationem, et fit potabilis quando condensatur: et iterum cum aqua desursum pluente descendit aliquid terrestre, quod non fuit sursum ductum ex aqua maris, sed ex arida. Et hoc terrestre, propter pondus, subsidet potabili et dulci; ut sic quod est subtilius, magis evaporet. Et ideo, propter continuam generationem et corruptionem, non deficit mare, sicut nec fluvii; nisi forte hoc accidat in aliquibus locis, tam in mari quam in fluviis, secundum aliquas determinatas periodos, ut supra dictum est. Nec tamen semper eaedem partes remanent aut maris aut terrae, sed solum tota moles utriusque. Sic enim oportet existimare de terra, sicut de mari, quod una pars sursum elevatur per exhalationem, et alia descendit; et quod etiam illa quae supernatant et quae descendunt, transmutant loca, ut sic quaelibet pars utriusque corrumpi et generari possit.	176. Then [182] from all the foregoing he gathers the cause of the salt of the sea. And he says that we must now say that some portion of the water of the sea is forever being raised aloft by evaporation and becomes drinkable when it is condensed; and further, that with the falling water there descends something terrestrial which was borne aloft, not from the water of the sea, but from dry land. And this terrestrial element because of its weight, sinks below the drinkable and sweet portion, with the result that the finer portion evaporates more. And therefore, as a result of continuous generation and evaporation, neither the sea nor rivers disappear: unless they happen to disappear in certain regions according to certain definite cycles, as mentioned earlier. Moreover, neither do the same parts of the sea or of the earth always remain, but only the whole bulks of both. Thus, we must think of the earth as we do of the sea, namely, that one part is borne aloft through exhalation and another part descends and, furthermore, that the parts on the surface exchange places with those that descend: as a result, every part of both can be corrupted and generated.
Considerandum est autem quod supra Aristoteles, causam salsedinis maris assignans, ubi tractavit de loco naturali aquae, dixit quod salsedo maris causatur per evaporationem eius quod est subtile et dulce. Haec autem causa nulla esset, si in aqua maris nihil alienum admisceretur: quia oporteret hoc etiam quod remanet, esse dulce et potabile, secundum simplicis aquae naturam. Et ideo, ad ostendendum quomodo aqua maris sit salsa, ostendit quod sit aliquid extraneum admixtum, quod subsidens post elevationem dulcis potabilis, reddit aquam maris salsam: et propter hoc dicit terrestre adustum esse admixtum vaporibus ex quibus generatur aqua. Unde, cum quaelibet pars maris sic generetur, relinquitur quod singulis partibus maris sit huiusmodi terrestre admixtum, quod secundum plurimum subsidet dulci et subtili, in maiori parte elevato.	It should be noted that Aristotle, in assigning the cause of the saltness of the sea when treating of the natural place of water above, stated that the saltness of the sea is caused by the evaporation of what is fine and sweet. But this would not be a cause, if nothing foreign were mixed in the sea water — since it would be necessary that what remained be sweet and drinkable, according to the nature of simple water. Consequently, in order to show how the water of the sea is salty, he shows that something foreign is mixed in it, which sinks (after the sweet potable water is elevated) and makes the water of the sea salty. On this account he says that burnt earth is mixed with the vapors from which water is generated. Hence, since each part of the sea is thus generated, it follows that a terrestrial adjunct of this sort is mixed with every part of the sea, and generally sinks below the sweet and fine, the major portion of which is elevated.
Et quia ex eo quod evaporat generatur aqua dulcis, omnis autem aqua fontium et fluviorum ex eo quod evaporat generatur, vel supra terram vel infra terram, consequens est ut aqua fontium et fluviorum sit dulcis, utpote propinqua principio generationis; aqua autem maris sit salsa, utpote residuum existens vaporum elevatorum a sole, et ultimus terminus in quem aquae generatae colliguntur.	And because sweet water is generated out of what evaporates, and all the water of springs and rivers is generated out of what evaporates, either on the surface of the earth or below the earth, it follows that the water of springs and rivers is sweet, simply because they are close to the source of generation; but the water of the sea is salty, being both the residue of vapors elevated by the sun and the final terminus into which the generated water is collected.
Deinde cum dicit: quod autem est in commixtione etc., manifestat quod ex commixtione terrestris causatur salsus sapor. Et ponit multa signa. Quorum primum est de vase cereo, quod si claudatur et ponatur in aqua, quod resudat interius efficitur dulce, tanquam depurato terrestri per ceram.	177. Then [183] he manifests that the salty savor is caused from a terrestrial mixture. And he gives many signs. The first of these concerns a waxen container sealed and set in water. Whatever seeps in becomes sweet, as though the terrestrial stuff were filtered out by the wax.
Aliud signum est, quod aqua maris plus ponderat quam dulcis.	Another sign is that sea water is heavier than the sweet.
Tertium signum est, quod aqua maris est grossior quam aqua fluviorum, ita quod naves oneratae plus profundantur in aquis fluviorum quam maris.	A third sign is that sea water is denser than river water, so that ships laden with cargo sink deeper in rivers than in the sea.
Quartum signum est, quod ova, si sint plena, supernatant in aqua quae fit salsa per admixtionem salis, et etiam supernatant in mari. Unde et mare videtur sicut lutum, propter grossitiem. Et hoc faciunt salientes, ut accipiant signum si sal sit bene mixtum aqua, ex hoc quod ova supernatant. Igitur et aqua maris est grossa per admixtionem alicuius terrestris ingrossantis.	The fourth sign is that eggs, if full, float in water to which salt has been added and even float in the sea. Hence the sea seems to be like mud on account of its density. Those who make brine take as a sign that the salt has been well mixed with the water, when eggs float on it. Therefore, sea water, too, is dense on account of an admixture of some gross earthy stuff.
Quintum signum est, quod in stagno Palestinae, quod est salsum vel amarum, si quis immerserit hominem vel asinum, non submergitur; et vestimenta ibi perfusa foedantur.	The fifth sign is that in the lake in Palestine which is salty or bitter, if anyone should immerse a man or ass, it does not sink; and clothing dipped in it becomes fetid.
Sextum autem signum est de quodam fonte aquae latae, idest salsae, in provincia Chaoniae, qui effluit in quendam fluvium dulcem, sed non habentem pisces; in quo quidem fluvio, propter admixtionem fontis, inventi sunt aliquando sales pro piscibus; cuius quidem aqua vertitur per decoctionem in sales, evaporante calido et humido. Huiusmodi autem sales non sunt spissi, sed subtiles sicut nix; et sunt debiliores aliis, et isti in cibariis magis delectant.	The sixth sign concerns a spring of "broad," i.e., salt, water in the province of Chaonia. This spring flows into a river of fresh water in which are no fish, but on account of the mixture contributed by this spring, salt is sometimes found instead of fish. When this water is boiled, salt is left after what is hot and liquid has evaporated. These salts are not coarse but fine as snow; they are weaker than other salts and give greater pleasure in foods.
Septimum autem signum est, quod in quodam loco calami et scirpi comburuntur, et eorum cinis, dum in aqua decoquitur, post infrigidationem efficitur sal, secundum terrestris combusti mixtionem, quam dixerat esse causam salsedinis. Unde oportet quod tam in aqua horum cinerum quam in aqua maris, combustio sit quae causet salsedinem. Et hinc est quod universaliter quaecumque aqua fluens fontium vel fluviorum est salsa, aliquando fuit calida, utpote ex terra ignita procedens: sed postea ignis extinguitur infra terram, et terra quae ex combustione fit sulphurea vel aliquid huiusmodi, remanet adhuc combusta ad modum calcis vel cineris: unde aqua transiens per eam fit salsa. Et non solum fit salsa, et salsedinem recipit aqua ex terra per quam transit, sed etiam alios sapores, ut manifestat per quaedam exempla: et littera plana est.	The seventh sign is that there is a region in which reeds and rushes are burned. When their ash is cooked in water and cooled, it becomes salty to a degree depending on the proportion of burned earthy matter, which he had said is the cause of saltiness. Hence, both in the water of these ashes, as well as in the water of the sea, there must be a combustion which causes saltiness. This is why universally any flowing water of springs and rivers which is salty, was once hot, as though proceeding from ignited earth. Afterwards the fire is extinguished within the earth, which, by the burning, having become sulphurous or something of the sort, still retains the marks of having been burnt, as lime and ashes do — so that water passing through it becomes salty. Indeed, such water not only becomes salty and receives saltness from the earth through which it passes, but also other savors, as he explains with examples (and this is plain in the text).
Ultimo autem recapitulat ea quae dicta sunt: et hoc etiam est planum in littera.	Finally, he sums up what has been said — and this is also plain in the text.

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Lecture 7
On the generation of winds

Chapter 4
περὶ δὲ πνευμάτων λέγωμεν, λαβόντες ἀρχὴν τὴν εἰρημένην ἡμῖν ἤδη πρότερον. ἔστι γὰρ δύ' εἴδη τῆς ἀναθυμιάσεως, ὥς φαμεν, ἡ μὲν ὑγρὰ ἡ δὲ ξηρά καλεῖται δ' ἡ μὲν ἀτμίς, ἡ δὲ τὸ μὲν ὅλον ἀνώνυμος, τῷ δ' ἐπὶ μέρους ἀνάγκη χρωμένους καθόλου προσαγορεύειν αὐτὴν οἷον καπνόν ἔστι δ' οὔτε τὸ ὑγρὸν ἄνευ τοῦ ξηροῦ οὔτε τὸ ξηρὸν ἄνευ τοῦ ὑγροῦ, ἀλλὰ πάντα ταῦτα λέγεται κατὰ τὴν ὑπεροχήν.	185 Let us proceed to the theory of winds. Its basis is a distinction we have already made. We recognize two kinds of evaporation, one moist, the other dry. The former is called vapour: for the other there is no general name but we must call it a sort of smoke, applying to the whole of it a word that is proper to one of its forms. The moist cannot exist without the dry nor the dry without the moist: whenever we speak of either we mean that it predominates.
φερομένου δὴ τοῦ ἡλίου κύκλῳ, καὶ ὅταν μὲν πλησιάζῃ, τῇ θερμότητι ἀνάγοντος τὸ ὑγρόν, πορρωτέρω (360a.) δὲ γιγνομένου διὰ τὴν ψύξιν συνισταμένης πάλιν τῆς ἀναχθείσης ἀτμίδος εἰς ὕδωρ (διὸ χειμῶνός τε μᾶλλον γίγνεται τὰ ὕδατα, καὶ νύκτωρ ἢ μεθ' ἡμέραν ἀλλ' οὐ δοκεῖ, διὰ τὸ λανθάνειν τὰ νυκτερινὰ τῶν μεθ' ἡμέραν μᾶλλον), τὸ δὴ κατιὸν ὕδωρ διαδίδοται πᾶν εἰς τὴν γῆν, ὑπάρχει δ' ἐν τῇ γῇ πολὺ πῦρ καὶ πολλὴ θερμότης, καὶ ὁ ἥλιος οὐ μόνον τὸ ἐπιπολάζον τῆς γῆς ὑγρὸν ἕλκει, ἀλλὰ καὶ τὴν γῆν αὐτὴν ξηραίνει θερμαίνων	186 Now when the sun in its circular course approaches, it draws up by its heat the moist evaporation: when it recedes the cold makes the vapour that had been raised condense back into water which falls and is distributed through the earth. (This explains why there is more rain in winter and more by night than by day: though the fact is not recognized because rain by night is more apt to escape observation than by day.) But there is a great quantity of fire and heat in the earth, and the sun not only draws up the moisture that lies on the surface of it, but warms and dries the earth itself.
τῆς δ' ἀναθυμιάσεως, ὥσπερ εἴρηται, διπλῆς οὔσης, τῆς μὲν ἀτμιδώδους τῆς δὲ καπνώδους, ἀμφοτέρας ἀναγκαῖον γίγνεσθαι. τούτων δ' ἡ μὲν ὑγροῦ πλέον ἔχουσα πλῆθος ἀναθυμίασις ἀρχὴ τοῦ ὑομένου ὕδατός ἐστιν, ὥσπερ εἴρηται πρότερον, ἡ δὲ ξηρὰ τῶν πνευμάτων ἀρχὴ καὶ φύσις πάντων.	187 Consequently, since there are two kinds of evaporation, as we have said, one like vapour, the other like smoke, both of them are necessarily generated. That in which moisture predominates is the source of rain, as we explained before, while the dry evaporation is the source and substance of all winds.
ταῦτα δὲ ὅτι τοῦτον τὸν τρόπον ἀναγκαῖον συμβαίνειν, καὶ ἐξ αὐτῶν τῶν ἔργων δῆλον καὶ γὰρ τὴν ἀναθυμίασιν διαφέρειν ἀναγκαῖον, καὶ τὸν ἥλιον καὶ τὴν ἐν τῇ γῇ θερμότητα ταῦτα ποιεῖν οὐ μόνον δυνατὸν ἀλλ' ἀναγκαῖόν ἐστιν.	188 That things must necessarily take this course is clear from the resulting phenomena themselves, for the evaporation that is to produce them must necessarily differ; and the sun and the warmth in the earth not only can but must produce these evaporations.
ἐπειδὴ δ' ἕτερον ἑκατέρας τὸ εἶδος, φανερὸν ὅτι διαφέρει, καὶ οὐχ ἡ αὐτή ἐστιν ἥ τε ἀνέμου φύσις καὶ ἡ τοῦ ὑομένου ὕδατος, καθάπερ τινὲς λέγουσιν τὸν γὰρ αὐτὸν ἀέρα κινούμενον μὲν ἄνεμον εἶναι, συνιστάμενον δὲ πάλιν ὕδωρ. ὁ μὲν οὖν ἀήρ, καθάπερ ἐν τοῖς πρὸ τούτων λόγοις εἰρήκαμεν, γίγνεται ἐκ τούτων ἡ μὲν γὰρ ἀτμὶς ὑγρὸν καὶ ψυχρόν (εὐόριστον μὲν γὰρ ὡς ὑγρόν, διὰ δὲ τὸ ὕδατος εἶναι ψυχρὸν τῇ οἰκείᾳ φύσει, ὥσπερ ὕδωρ μὴ θερμανθέν), ὁ δὲ καπνὸς θερμὸν καὶ ξηρόν ὥστε καθάπερ ἐκ συμβόλων, συνίσταιτο ἂν ὁ ἀὴρ ὑγρὸς καὶ θερμός.	189 Since the two evaporations are specifically distinct, wind and rain obviously differ and their substance is not the same, as those say who maintain that one and the same air when in motion is wind, but when it condenses again is water. Air, as we have explained in an earlier book, is made up of these as constituents. Vapour is moist and cold (for its fluidity is due to its moistness, and because it derives from water it is naturally cold, like water that has not been warmed): whereas the smoky evaporation is hot and dry. Hence each contributes a part, and air is moist and hot.
καὶ γὰρ ἄτοπον εἰ ὁ περὶ ἑκάστους περικεχυμένος ἀὴρ οὗτος γίγνεται κινούμενος πνεῦμα, καὶ ὅθεν ἂν τύχῃ κινηθείς, ἄνεμος ἔσται, ἀλλ' οὐ καθάπερ τοὺς ποταμοὺς ὑπολαμβάνομεν οὐχ ὁπωσοῦν τοῦ ὕδατος εἶναι ῥέοντος, οὐδ' ἂν ἔχῃ πλῆθος, ἀλλὰ δεῖ πηγαῖον εἶναι τὸ ῥέον οὕτω γὰρ καὶ περὶ τῶν ἀνέμων ἔχει κινηθείη γὰρ ἂν πολὺ πλῆθος ἀέρος ὑπό τινος μεγάλης πτώσεως, οὐκ ἔχον ἀρχὴν οὐδὲ πηγήν.	190 It is absurd that this air that surrounds us should become wind when in motion, whatever be the source of its motion on the contrary the case of winds is like that of rivers. We do not call water that flows anyhow a river, even if there is a great quantity of it, but only if the flow comes from a spring. So too with the winds; a great quantity of air might be moved by the fall of some large object without flowing from any source or spring.
μαρτυρεῖ δὲ τὰ γιγνόμενα τοῖς εἰρημένοις διὰ γὰρ τὸ συνεχῶς μὲν μᾶλλον δὲ καὶ ἧττον καὶ πλείω καὶ ἐλάττω γίγνεσθαι τὴν (360b.) ἀναθυμίασιν, ἀεὶ νέφη τε καὶ πνεύματα γίγνεται κατὰ τὴν ὥραν ἑκάστην ὡς πέφυκεν διὰ δὲ τὸ ἐνίοτε μὲν τὴν ἀτμιδώδη γίγνεσθαι πολλαπλασίαν ὁτὲ δὲ τὴν ξηρὰν καὶ καπνώδη, ὁτὲ μὲν ἔπομβρα τὰ ἔτη γίγνεται καὶ ὑγρά, ὁτὲ δὲ ἀνεμώδη καὶ αὐχμοί. ὁτὲ μὲν οὖν συμβαίνει καὶ τοὺς αὐχμοὺς καὶ τὰς ἐπομβρίας πολλοὺς ἅμα καὶ κατὰ συνεχῆ γίγνεσθαι χώραν, ὁτὲ δὲ κατὰ μέρη πολλάκις γὰρ ἡ μὲν κύκλῳ χώρα λαμβάνει τοὺς ὡραίους ὄμβρους ἢ καὶ πλείους, ἐν δέ τινι μέρει ταύτης αὐχμός ἐστιν ὁτὲ δὲ τοὐναντίον τῆς κύκλῳ πάσης ἢ μετρίοις χρωμένης ὕδασιν ἢ καὶ μᾶλλον αὐχμώσης, ἕν τι μόριον ὕδατος ἄφθονον λαμβάνει πλῆθος. αἴτιον δ' ὅτι ὡς μὲν τὰ πολλὰ τὸ αὐτὸ πάθος ἐπὶ πλείω διήκειν εἰκὸς χώραν, διὰ τὸ παραπλησίως κεῖσθαι πρὸς τὸν ἥλιον τὰ σύνεγγυς, ἐὰν μή τι διάφορον ἔχωσιν ἴδιον οὐ μὴν ἀλλ' ἐνίοτε κατὰ τοδὶ μὲν τὸ μέρος ἡ ξηρὰ ἀναθυμίασις ἐγένετο πλείων, κατὰ δὲ τὸ ἄλλο ἡ ἀτμιδώδης, ὁτὲ δὲ τοὐναντίον. καὶ αὐτοῦ δὲ τούτου αἴτιον τὸ ἑκατέραν μεταπίπτειν εἰς τὴν τῆς ἐχομένης χώρας ἀναθυμίασιν, οἷον ἡ μὲν ξηρὰ κατὰ τὴν οἰκείαν ῥεῖ χώραν, ἡ δ' ὑγρὰ πρὸς τὴν γειτνιῶσαν, ἢ καὶ εἰς τῶν πόρρω τινὰ τόπων ἀπεώσθη ὑπὸ πνευμάτων ὁτὲ δὲ αὕτη μὲν ἔμεινεν, ἡ δ' ἐναντία ταὐτὸν ἐποίησεν. καὶ συμβαίνει τοῦτο πολλάκις, ὥσπερ ἐπὶ τοῦ σώματος, ἐὰν ἡ ἄνω κοιλία ξηρὰ ᾖ, τὴν κάτω ἐναντίως διακεῖσθαι, καὶ ταύτης ξηρᾶς οὔσης ὑγρὰν εἶναι τὴν ἄνω καὶ ψυχράν, οὕτω καὶ περὶ τοὺς τόπους ἀντιπεριίστασθαι καὶ μεταβάλλειν τὰς ἀναθυμιάσεις.	191 The facts bear out our theory. It is because the evaporation takes place uninterruptedly but differs in degree and quantity that clouds and winds appear in their natural proportion according to the season; and it is because there is now a great excess of the vaporous, now of the dry and smoky exhalation, that some years are rainy and wet, others windy and dry. Sometimes there is much drought or rain, and it prevails over a great and continuous stretch of country. At other times it is local; the surrounding country often getting seasonable or even excessive rains while there is drought in a certain part; or, contrariwise, all the surrounding country gets little or even no rain while a certain part gets rain in abundance. The reason for all this is that while the same affection is generally apt to prevail over a considerable district because adjacent places (unless there is something special to differentiate them) stand in the same relation to the sun, yet on occasion the dry evaporation will prevail in one part and the moist in another, or conversely. Again the reason for this latter is that each evaporation goes over to that of the neighbouring district: for instance, the dry evaporation circulates in its own place while the moist migrates to the next district or is even driven by winds to some distant place: or else the moist evaporation remains and the dry moves away. Just as in the case of the body when the stomach is dry the lower belly is often in the contrary state, and when it is dry the stomach is moist and cold, so it often happens that the evaporations reciprocally take one another's place and interchange.
ἔτι δὲ μετά τε τοὺς ὄμβρους ἄνεμος ὡς τὰ πολλὰ γίγνεται ἐν ἐκείνοις τοῖς τόποις καθ' οὓς ἂν συμπέσῃ γενέσθαι τοὺς ὄμβρους, καὶ τὰ πνεύματα παύεται ὕδατος γενομένου. ταῦτα γὰρ ἀνάγκη συμβαίνειν διὰ τὰς εἰρημένας ἀρχάς ὕσαντός τε γὰρ ἡ γῆ ξηραινομένη ὑπό τε τοῦ ἐν αὐτῇ θερμοῦ καὶ ὑπὸ τοῦ ἄνωθεν ἀναθυμιᾶται, τοῦτο δ' ἦν ἀνέμου σῶμα καὶ ὅταν ἡ τοιαύτη ἀπόκρισις ᾖ καὶ ἄνεμοι κατέχωσι, παυομένων διὰ τὸ ἀποκρίνεσθαι τὸ θερμὸν ἀεὶ καὶ ἀναφέρεσθαι εἰς τὸν ἄνω τόπον συνίσταται ἡ ἀτμὶς ψυχομένη καὶ γίγνεται ὕδωρ (361a.) καὶ ὅταν εἰς ταὐτὸν συνωσθῶσι τὰ νέφη καὶ ἀντιπεριστῇ εἰς αὐτὰ ἡ ψύξις, ὕδωρ γίγνεται καὶ καταψύχει τὴν ξηρὰν ἀναθυμίασιν. παύουσί τε οὖν τὰ ὕδατα γιγνόμενα τοὺς ἀνέμους, καὶ παυομένων αὐτὰ γίγνεται διὰ ταύτας τὰς αἰτίας.	192 Further, after rain wind generally rises in those places where the rain fell, and when rain has come on the wind ceases. These are necessary effects of the principles we have explained. After rain the earth is being dried by its own heat and that from above and gives off the evaporation which we saw to be the material cause of. wind. Again, suppose this secretion is present and wind prevails; the heat is continually being thrown off, rising to the upper region, and so the wind ceases; then the fall in temperature makes vapour form and condense into water. Water also forms and cools the dry evaporation when the clouds are driven together and the cold concentrated in them. These are the causes that make wind cease on the advent of rain, and rain fall on the cessation of wind.
ἔτι δὲ τοῦ γίγνεσθαι μάλιστα πνεύματα ἀπό τε τῆς ἄρκτου καὶ μεσημβρίας τὸ αὐτὸ αἴτιον πλεῖστοι γὰρ βορέαι καὶ νότοι γίγνονται τῶν ἀνέμων ὁ γὰρ ἥλιος τούτους μόνους οὐκ ἐπέρχεται τοὺς τόπους, ἀλλὰ πρὸς τούτους καὶ ἀπὸ τούτων, ἐπὶ δυσμὰς δὲ καὶ ἐπ' ἀνατολὰς ἀεὶ φέρεται διὸ τὰ νέφη συνίσταται ἐν τοῖς πλαγίοις, καὶ γίγνεται προσιόντος μὲν ἡ ἀναθυμίασις τοῦ ὑγροῦ, ἀπιόντος δὲ πρὸς τὸν ἐναντίον τόπον ὕδατα καὶ χειμῶνες. διὰ μὲν οὖν τὴν φορὰν τὴν ἐπὶ τροπὰς καὶ ἀπὸ τροπῶν θέρος γίγνεται καὶ χειμών, καὶ ἀνάγεταί τε ἄνω τὸ ὕδωρ καὶ γίγνεται πάλιν ἐπεὶ δὲ πλεῖστον μὲν καταβαίνει ὕδωρ ἐν τούτοις τοῖς τόποις ἐφ' οὓς τρέπεται καὶ ἀφ' ὧν, οὗτοι δέ εἰσιν ὅ τε πρὸς ἄρκτον καὶ μεσημβρίαν, ὅπου δὲ πλεῖστον ὕδωρ ἡ γῆ δέχεται, ἐνταῦθα πλείστην ἀναγκαῖον γίγνεσθαι τὴν ἀναθυμίασιν παραπλησίως οἷον ἐκ χλωρῶν ξύλων καπνόν, ἡ δ' ἀναθυμίασις αὕτη ἄνεμός ἐστιν, εὐλόγως ἂν οὖν ἐντεῦθεν γίγνοιτο τὰ πλεῖστα καὶ κυριώτατα τῶν πνευμάτων. καλοῦνται δ' οἱ μὲν ἀπὸ τῆς ἄρκτου βορέαι, οἱ δὲ ἀπὸ τῆς μεσημβρίας νότοι.	193 The cause of the predominance of winds from the north and from the south is the same. (Most winds, as a matter of fact, are north winds or south winds.) These are the only regions which the sun does not visit: it approaches them and recedes from them, but its course is always over the west and the east. Hence clouds collect on either side, and when the sun approaches it provokes the moist evaporation, and when it recedes to the opposite side there are storms and rain. So summer and winter are due to the sun's motion to and from the solstices, and water ascends and falls again for the same reason. Now since most rain falls in those regions towards which and from which the sun turns and these are the north and the south, and since most evaporation must take place where there is the greatest rainfall, just as green wood gives most smoke, and since this evaporation is wind, it is natural that the most and most important winds should come from these quarters. (The winds from the north are called Boreae, those from the south Noti.)

Postquam philosophus determinavit de mari, cuius salsedo causatur ex admixtione exhalationis siccae terrestris, consequenter determinat de ventis, qui ab eadem exhalatione sicca causantur. Et dividitur in partes duas:	178. After determining about the sea, whose saltness is caused from an admixture of the dry earthy exhalation, the Philosopher subsequently determines about the winds, which are caused by the same dry exhalation. And it is divided into two sections:
in prima determinat de ipsis ventis; in secunda de quibusdam passionibus ex ventis causatis, ibi: de agitatione autem et motu et cetera.	In the first he determines about the winds themselves, at 179; In the second about certain phenomena caused from winds (c. 7).
Prima iterum dividitur in duas:	The first is divided into two parts:
in prima determinat de ventis in communi; in secunda de speciebus ventorum, ibi: de positione et cetera.	In the first he determines about winds in general; In the second about the species of winds (c. 6).
Prima dividitur in tres partes:	The first is divided into three parts:
in prima determinat de generatione ventorum; in secunda de motu locali eorum, ibi: latio autem ipsorum etc.; in tertia de augmento et quietatione ipsorum, ibi: sol autem et cessare et cetera.	In the first he determines about the generation of winds, at 179; In the second about their local motion (L. 8); In the third about their increase and abatement (L. 9).
Circa primum tria facit:	Regarding the first he does three things:
primo praemittit principia generationis ventorum; secundo ponit modum generationis eorum, ibi: exhalatione autem sicut etc.; tertio manifestat quod dictum est, ibi: hoc autem quod isto modo et cetera.	First, he lays down the principles of the generation of winds, at 179; Secondly, he describes the manner of their generation, at 181; Thirdly, he manifests what has been said, at 182.
Circa primum duo facit. Primo assignat principium materiale ventorum. Et dicit quod, cum dicendum est de spiritibus, idest de ventis, oportet resumere hoc principium, quod iam prius dictum est, scilicet quod sunt duae species exhalationis: una quidem humida, quae vocatur vapor; alia autem sicca, quae, quia non habet nomen commune, a quadam sui parte vocetur fumus; nam fumus proprie dicitur exhalatio sicca lignorum ignitorum. Duae autem hae exhalationes non sic discretae sunt ad invicem, quod humidum sit sine sicco, et siccum sine humido: sed ab eo quod excedit, utraque denominatur.	179. Regarding the first he does two things: first he assigns the material principle of winds [185] and says that, since "spirits," i.e., winds, are to be discussed, it is necessary to recall this principle, already enunciated, namely, that there are two kinds of exhalation: one, indeed, is the moist, which is called "vapor"; the other is the dry, which, having no common name, is called "smoke" from one of its forms: for smoke is, strictly speaking, the dry exhalation of burning wood. Now these two exhalations are not so independent of each other that the moist is without the dry, and the dry without the moist — rather they are denominated one or the other by that which is predominant in a given case.
Secundo ibi: lato autem sole etc., ponit principium efficiens, quod est motus solis. Et dicit quod cum sol suo motu appropinquat ad aliquam partem terrae, sua caliditate elevat humidum: eo autem elongato, vapor elevatus, propter frigiditatem, condensatur in aquam. Et inde est quod in hieme magis pluit quam in aestate, et in nocte quam in die, licet aquae nocturnae lateant propter somnum. Aqua autem pluens dividitur per terram, et bibitur ab ea. In terra autem est multum de calore, ex actione solis et aliorum corporum caelestium; et sol desuper eam calefaciens, non solum attrahit per evaporationem humidum quod supernatat terrae, ut puta aquam maris, fluviorum et stagnorum, sed etiam ipsam terram desiccat, attrahens humorem imbibitum in terra. Quod ergo exhalat ab humido supernatante, dicitur vapor: quod autem exhalat per desiccationem terrae, dicitur fumus; sicut in simili dicitur fumus, quod exhalat a lignis calefactis.	180. Secondly [186], he mentions the efficient principle, which is the motion of the sun. And he says that when the sun in its course approaches a given region of the earth, its warmth elevates the moist; as the sun recedes, this raised vapor is condensed into water on account of the cold. This is why there is more rain in winter than in summer, and more at night than during the day, although night-rains go unobserved because of sleep. The rain water is divided up in the earth and drunk in by it. In the earth much heat exists, caused by the action of the sun and other heavenly bodies. And the sun overhead, heating the earth, not only draws aloft the moisture resting on the surface of the earth — for example, the water of the sea, rivers and ponds — but also dries out the earth itself and draws up the moisture drunk by the earth. Consequently the exhalation it produces from the moisture resting on the earth is called "vapor," but the exhalation that results from its drying out the earth is called "smoke," just as in a parallel case, the exhalation from heated wood is called "smoke. "
Deinde cum dicit: exhalatione autem sicut etc., determinat generationem ventorum. Et dicit quod, cum exhalatio duplex sit, ut dictum est, una vaporosa et alia fumosa, necesse est quod ex motu solis fiat utraque. Ea autem quae plus habet de humido, est principium pluentis aquae, ut supra dictum est (quod dicit propter hoc, quia supra dixerat ei admisceri aliquid de exhalatione sicca): sicca autem exhalatio est principium ventorum.	181. Then [187] he determines the generation of winds and says that since exhalations are of two kinds, as has been said, one vaporous and one smoky, it is necessary that, from the sun's motion, both should come about. The one with more moisture is the source of rain water, as said above (which he says, because he had previously stated that some dry exhalation is mixed with it); but the dry exhalation is the source of winds.
Deinde cum dicit: hoc autem quod isto modo etc., manifestat quod dictum est de generatione ventorum. Et circa hoc tria facit:	182. Then [188] he manifests what has been said about the generation of winds. About this he does three things:
primo hoc manifestat per rationem; secundo ex hoc quod dictum est, excludit falsas opiniones de ventis, ibi: quoniam autem altera etc.; tertio hoc manifestat per signa, ibi: attestantur autem quae fiunt et cetera.	First, he manifests it with an argument; Secondly, from what has been said, he excludes false opinions about winds, at 183; Thirdly, he manifests this with signs, at 185.
Dicit ergo primo quod, cum sit duplex exhalatio, propter duo ex quibus consurgit, scilicet terram et aquam, possibile est, immo necessarium, quod sol et caliditas quae est circa terram, possit causare resolutionem utriusque exhalationis.	He says therefore first [188] that since exhalations are of two kinds, on account of the two sources from which they are derived, namely, earth and water, it is possible, even necessary, that the sun and the heat which environs the earth can cause the resolution of both exhalations.
Deinde cum dicit: quoniam autem altera etc., excludit falsas opiniones de ventis. Et primo quantum ad hoc, quod dicebant quod eadem natura est venti et pluviae. Quod quidem excludit per hoc, quod diversorum diversi sunt effectus: unde, cum exhalationes differant secundum siccum et humidum, necesse est quod non sit eadem natura venti et natura aquae pluentis, ut quidam posuerunt, dicentes quod idem aer quando movetur, est ventus, quando autem condensatur, fit aqua.	183. Then [189] he dismisses false theories about the winds. First, the opinion of those who said that the natures of wind and of rain are the same. This he excludes by the fact that the effects of diverse things are themselves diverse: hence, since the exhalations differ on the basis of dry and moist, it is necessary that the nature of wind and of rain water be not the same, as some supposed who said that it is the same air which, when moved, is wind, and when condensed, becomes water.
Sed, sicut dictum est in libro de generatione, aer habet aliquid vaporis et aliquid fumi. Vapor eius est frigidus et humidus, et bene terminabilis, propter grossitiem: et hoc convenit aeri inquantum est humidus. Sic etiam vapor, qui elevatur ab aqua, est frigidus secundum suam naturam, sicut et aqua non calefacta: sicut autem aqua calefacta remanet frigida secundum naturam, ita et vapor. Sed fumus est calidus et siccus: siccus quidem propter terram, calidus autem propter ignem. Unde manifeste patet quod superior aer, qui est calidus et humidus, habet similitudinem cum utroque.	But as stated in On Generation, air has something of vapor and of smoke. Its vapor is cold and moist and well-definable by its density; and this belongs to air in so far as it is moist. Thus also vapor, which is borne up from water, is cold by its very nature, as also is unwarmed water: just as warmed water remains cold according to nature, so also vapor. But smoke is hot and dry: because of the earth, it is dry; because of fire, it is hot. Hence it is manifestly plain that the upper air, which is hot and moist, bears a likeness to both.
Secundo ibi: etenim inconveniens etc., excludit falsam opinionem quantum ad hoc, quod dicebant quod ventus nihil aliud est quam aer motus. Et dicit quod inconveniens est, si quis existimet quod iste aer qui circumstat unumquemque nostrum, quando movetur est ventus; vel quod unusquisque motus qui accidit in aere, sit ventus; sicut etiam non existimamus fluvium esse aquam qualitercumque fluentem, etiam si multa sit, sed solum quando fluit ex aliquo principio determinato, quod est fons ex terra scaturiens. Sic etiam est de ventis: non enim est ventus, si aer moveatur aliquo modo casu, etiam in magna multitudine, nisi habeat principium, quasi fontem, exhalationem siccam elevatam. Sic igitur non est verum quod aer motus est ventus: tum quia quandoque parvus aer movetur, tum quia non habet principium.	184. Secondly [190], he dismisses the false opinion as to its tenet that wind is nothing more than air in motion. And he says that it is unacceptable for anyone to suppose that the air which surrounds each of us is, when in motion, wind; or that every movement occurring in air is wind; just as also we do not suppose any water at all that flows, even if it be a large amount, to be a river, but only when it flows from some determinate source, which is a spring gushing from the earth. The same applies to winds: it is not a wind, if air, even in large amounts, is moved in some chance way, but only when it has as its source, as though its spring, a raised dry exhalation. Consequently, it is not true that air in motion is wind: both because sometimes a small amount of air is in motion, and because it does not have a starting-point.
Deinde cum dicit: attestantur autem quae fiunt etc., manifestat quod dictum est de generatione ventorum, per signa. Et dividitur in partes tres, secundum tria signa quae ponit: secunda pars incipit ibi: adhuc autem post imbres etc.; tertia ibi: adhuc autem fiendi et cetera.	185. Then [191] he manifests through signs what has been said about the generation of winds. And it is divided into three parts according to the three signs he gives: The second part begins at 186; The third part at 187.
Dicit ergo primo quod ea quae fiunt circa ventos et pluvias, attestantur his quae dicta sunt de generatione eorum. Quia enim continue fit exhalatio, licet quandoque magis et quandoque minus, propter hoc nubes, ex quibus causantur pluviae, et venti semper fiunt, secundum quod natura temporis habet: quia quandoque magis fit, quandoque minus, secundum diversam temporis conditionem. Et quia quandoque exhalatio vaporosa plus elevatur, quandoque autem plus de fumosa, secundum diversos effectus solis et stellarum, ideo quandoque fiunt anni magis pluviosi et humidi, quandoque autem magis ventosi et sicci.	He says therefore first [191] that the phenomena attending winds and rains support what has been said about their generation. For because exhalations are continually occurring, now more, now less, clouds producing rain, and winds are forever being generated according to the nature of the season: for according to the varying condition of the season more occurs at one time and less at another. And because more vaporous exhalation is sometimes lifted up and more of the smoky at other times, depending on the diverse effects of the sun and stars, the consequence is that sometimes the years are more rainy and wet, and sometimes more windy and dry.
Quod quidem contingit dupliciter: uno modo secundum unam totam regionem continuam, in qua aliquo tempore multiplicantur pluviae, et aliquo tempore venti; alio modo fit secundum partes. Quandoque enim in una parte unius regionis accidunt multi imbres, in alia vero parte eiusdem regionis accidit multa siccitas: quandoque etiam contingit contrarium, quod tota regio circumstans habet mediocres aquas, vel etiam excedit in siccitate, alia vero abundat multitudine aquarum. Et huius causam assignat, dicens quod causa huius est, quod verisimile est quod eadem passio vel siccitatis vel humiditatis, pertingat frequentius ad multam regionem, ex hoc quod loca quae sunt prope, eandem habent positionem vel situm respectu solis, qui est causa pluviarum et ventorum: nisi forte aliqua habeat aliquid proprium quod immutet dispositionem eius, ut puta montes vel aquas. Sed quamvis ut plurimum hoc accidat, quod tota regio eandem participet passionem, tamen quandoque contingit quod secundum unam partem unius regionis abundet exhalatio sicca, ad generandum ventos, aliquando autem humida, ad generandum pluvias: et quandoque contingit contrarium, ut scilicet ubi olim abundavit pluvia, ibi nunc abundet ventus.	Now this happens in two ways: in one way, with respect to some whole continuous region, where at one time there are many rainstorms and at another many winds; in another way, with respect to various parts. For sometimes in one area of one region many rainstorms occur, and in another area of the same region there is a great drought; at other times the opposite occurs, namely, that the entire surrounding region has middling rain or even drought, while the other has an excessive rainfall. And he assigns the reason, saying that the cause of this is that it is reasonable that the same passion of dryness or dampness should extend often to a whole region, because places that are close to one another have the same position in relation to the sun, which is the cause of rain or of winds — unless one place happens to have a special characteristic which changes its disposition, such as mountains or bodies of water. But although it most frequently happens that an entire region shares the same weather passion, yet it sometimes happens that one locality of a region has an abundance of dry exhalation to generate winds, whereas another abounds in the moist to generate rains; or the opposite happens, i.e., a region that once abounded in rain now abounds in wind.
Et huiusmodi diversitatis causa est, quia contingit de utraque exhalatione quod transeat in exhalationem alterius regionis habitae, idest consequenter se habentis: ut puta, quandoque sicca exhalatio facit fluxum ventorum in illa regione unde elevatur, sed exhalatio humida a ventis impellitur ad aliquam regionem propinquam terrae ventosae; et aliquando remanet humida, et transfertur sicca. Sicut enim in corpore animalis aliquando superior ventositas, quae ex stomacho exhalat, contrarie disponitur inferiori, quae exhalat ex intestinis; sic et circa loca accidit quod patiuntur quandam contraiacentiam ex permutatione exhalationum; scilicet dum in regione ex qua transfertur exhalatio humida, abundat siccitas, et in illa ad quam transfertur, abundat humiditas.	The reason for this diversity is that both types of exhalation can cross over into the exhalation of a "had," i.e., following [adjacent] region: for example, the dry exhalation sometimes blows up a wind in the very region from which it was elevated, but the moist exhalation is blown to a region next to the windy one; while sometimes the moist exhalation may remain and the dry migrate. For, just as in the body of an animal the upper flatulence which exhales from the stomach is in a condition contrary to the lower which exhales from the intestines, so, with respect to places, it happens that from the interchanging of exhalations, they undergo a certain counter-state, so that while dryness prevails in the region from which the moist exhalation is transported, moisture abounds in the region to which it is carried.
Deinde cum dicit: adhuc autem post imbres etc., ponit secundum signum. Et dicit quod pluries fit ventus post pluvias in locis in quibus pluit; et e converso venti cessant aqua pluente. Et hoc accidit propter hoc quod dictum est de principiis pluviae et ventorum, quia scilicet unum eorum fit ex exhalatione sicca, aliud ex humida. Quia cum pluvia ceciderit et humectaverit terram, iterato a terra exhalat exhalatio sicca, quae est materia ventorum, desiccata ipsa terra tum a caliditate intrinseca, tum a superiori caliditate solis. Et haec est causa quare post pluvias fiunt venti: cum scilicet venti invalescant per separationem talis elevationis a terra. Et cessant propter hoc, quod ex virtute caloris iterato separatur calidus vapor a terra, et elevatur in superiorem locum, et propter frigiditatem ibi condensatur, et fit pluvia: et haec est causa quare post ventos pluviae superveniunt. Nec solum pluviae succedunt ventis, sed etiam destruunt eos: quia cum nubes a vento adunentur in unum locum, frigiditas circumstans condensat eas, et generantur aquae; aqua vero infrigidat et humectat exhalationem siccam, quae erat materia ventorum. Unde manifestum est quod aquae fluentes faciunt cessare ventos, et succedunt, ipsis cessantibus, pluviae, propter praedictas causas. Et hoc accipit ut signum ad ostendendum quod ventus et pluvia fiunt ex causis contrariis.	186. Then at [192] he gives the second sign, and says that in the places in which it has rained, a wind often arises after the rain; and conversely, the winds stop when it rains. And this occurs because of what has been said about the sources of rain and winds, namely, that the one is from the dry exhalation and the other from the moist. For when the rain has fallen and wet the earth, the dry exhalation, which is the stuff of winds, is once more exhalated from the earth dried out by its own inherent warmth or by that of the sun above. And this is the cause of winds occurring after rains: namely, since winds are increased by the separation of such elevation from the earth. But they cease because the vigor of heat once more separates the warm vapor from the earth, and it is elevated to a higher place where the cold condenses it and forms rain — which is the reason for rains occurring after winds. Rains not only succeed winds but destroy them: for, when clouds are pushed together by a wind into one place, the surrounding cold condenses them and water is generated; the water then cools and dampens the dry exhalation which was the stuff of the winds. Hence it is plain that flowing waters make winds cease, and that, when they cease, the rain succeeds them, for the reasons given. And he takes this as a sign that wind and rain come from contrary causes.
Deinde cum dicit: adhuc autem fiendi etc., ponit tertium signum quod venti generentur ab exhalatione sicca. Haec enim est causa quare fiunt venti maxime ab ursa, idest a Septentrione (quod vocatur ab ursa, eo quod duae ursae, maior et minor, circumeunt polum Septentrionalem de propinquo), et iterum a meridie: inter omnes enim ventos magis abundant Boreae, qui sunt a Septentrione, et Austri, qui sunt a meridie.	187. Then [193] he gives a third sign that winds are generated from the dry exhalation. For this is the cause why winds blow mostly "from the Bear," i.e., from the north (described as "from the Bear," because the two "bears," Big and Little, circle closely around the North Pole) and from the south — for it is a fact that most winds are boreal, i.e., from the north, or austral, i.e., from the south.
Et huius causa est, quia super ista loca non movetur sol, sed accedit ad ea et recedit ab eis. Ad polum quidem Septentrionalem maxime accedit, cum pervenit ad principium cancri: et tunc incipit ab eo recedere continue magis, quousque perveniat ad principium Capricorni; tunc enim maxime accedit ad polum contrarium, a quo iterum recedens circulariter redit ad principium cancri. Et propter hoc haec duo puncta, scilicet principium cancri et Capricorni, dicuntur tropica, idest conversiva: et quando est in principio cancri, fit versio aestiva, quando autem est in principio Capricorni, versio hiemalis. Ultra autem haec duo signa non accedit ad alterutrum polorum. Sed super orientem et occidentem semper fertur. Et ideo in locis qui lateraliter se habent ad viam solis, multae nubes congregantur: quia appropinquante sole, fit exhalatio humidi propter calorem; recedente autem sole ad locum contrarium, fiunt pluviae et hiemalia frigora.	The reason for this is that the sun is not moved over those places but approaches them and then departs. The closest it gets to the north pole is the beginning of Cancer; then it departs farther and farther, until it reaches the beginning of Capricorn, which is its maximum approach to the contrary pole, from which, departing once more, it cyclically returns to the beginning of Cancer. For this reason, these two points, namely, the beginnings of Cancer and of Capricorn, are called "tropics," i.e., turning-points: when the sun is in the beginning of Cancer, the summer turn occurs; when it is in the beginning of Capricorn, the winter turn. Beyond these points the sun gets no closer to either pole. But it is always moving over the east and west. And therefore, in the places lateral to the sun's course many clouds gather, because, as the sun approaches, a moist exhalation is formed on account of the heat; after the sun recedes to its opposite place, rains and wintry cold arise.
Sic igitur propter hoc quod sol accedit ad tropicos vel recedit, fit aestas et hiems, et elevatur aqua per evaporationem, et iterum pluit. Quia cum in caelo accedit sol ad principium cancri, fit aestas nobis, et elevantur plurimi vapores propter calorem ex vicinitate solis: cum autem accedit ad principium Capricorni, fit nobis frigus et hiems, et multitudo pluviarum, propter elongationem solis a nobis. E converso autem accidit in illa parte terrae sita ad alium polum. Quia igitur in istis locis qui sunt ad meridiem et Septentrionem, plurima aqua descendit, oportet quod ibi etiam plurima fiat exhalatio; sicut ex lignis viridibus et humidis maior exhalat fumus quam ex siccis. Unde, cum exhalatio talis sit principium ventorum, rationabile est quod plures et maximi ventorum sint, qui flant a meridie et vocantur Austri, et qui a Septentrione et vocantur Boreae.	And so, depending on whether the sun is approaching the tropics or departing, summer and winter are produced, and water is raised aloft by evaporation and once more descends. For when the sun in the heavens attains the beginning of Cancer, our summer is produced, and an abundance of vapors are elevated on account of the heat produced by the nearness of the sun; but when it comes to the beginning of Capricorn, cold and winter are produced for us, and many rains come, because of the distance of the sun from us. But the opposite is occurring in that part of the earth situated at the other pole. Since in those regions to the south and north the most water falls, the greatest amount of exhalation must also occur there, just as more smoke is produced from wood green and damp than from dry. Hence, since an exhalation of that type is the source of winds, it is reasonable that more winds and the strongest ones blow from the south and are called "austral," and from the north and are called "boreal."
Considerandum est tamen quod Aristoteles hic dicit Austrum flare ab alio polo, secundum aliorum opinionem: sed contrarium infra dicet secundum suam opinionem, et aliam causam assignabit de vehementia huius venti.	It should be noted that Aristotle here says that the south wind blows from the other pole according to the opinions of others; but later on he will give the opposite as his own opinion and will assign a different cause of the vigor of this wind.

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Lecture 8
On the local motion of the winds

Chapter 4 cont.
ἡ δὲ φορὰ λοξὴ αὐτῶν ἐστιν περὶ γὰρ τὴν γῆν πνέουσιν εἰς ὀρθὸν γιγνομένης τῆς ἀναθυμιάσεως, ὅτι πᾶς ὁ κύκλῳ ἀὴρ συνέπεται τῇ φορᾷ.	194 The course of winds is oblique: for though the evaporation rises straight up from the earth, they blow round it because all the surrounding air follows the motion of the heavens.
διὸ καὶ ἀπορήσειεν ἄν τις ποτέρωθεν ἡ ἀρχὴ τῶν πνευμάτων ἐστί, πότερον ἄνωθεν ἢ κάτωθεν ἡ μὲν γὰρ κίνησις ἄνωθεν καὶ πρὶν πνεῖν, ὁ δ' ἀὴρ ἐπίδηλος, κἂν ᾖ νέφος ἢ ἀχλύς σημαίνει γὰρ κινουμένην πνεύματος ἀρχὴν πρὶν φανερῶς ἐληλυθέναι τὸν ἄνεμον, ὡς ἄνωθεν αὐτῶν ἐχόντων τὴν ἀρχήν. ἐπεὶ δ' ἐστὶν ἄνεμος πλῆθός τι τῆς ξηρᾶς ἐκ γῆς ἀναθυμιάσεως κινούμενον περὶ τὴν γῆν, δῆλον ὅτι τῆς μὲν κινήσεως ἡ ἀρχὴ ἄνωθεν, τῆς δὲ ὕλης καὶ τῆς γενέσεως κάτωθεν ᾗ μὲν γὰρ ῥευσεῖται τὸ ἀνιόν, ἐκεῖθεν τὸ αἴτιον ἡ γὰρ φορὰ τῶν πορρωτέρω κυρία τῆς γῆς καὶ ἅμα κάτωθεν μὲν εἰς ὀρθὸν ἀναφέρεται, καὶ πᾶν ἰσχύει μᾶλλον ἐγγύς, ἡ δὲ τῆς γενέσεως ἀρχὴ δῆλον ὡς ἐκ τῆς (361b.) γῆς ἐστιν.	195 Hence the question might be asked whether winds originate from above or from below. The motion comes from above: before we feel the wind blowing the air betrays its presence if there are clouds or a mist, for their motion shows that the wind has begun to blow before it has actually reached us; and this implies that the source of winds is above. But since wind is defined as 'a quantity of dry evaporation from the earth moving round the earth', it is clear that while the origin of the motion is from above, the matter and the generation of wind come from below. The oblique movement of the rising evaporation is caused from above: for the motion of the heavens determines the processes that are at a distance from the earth, and the motion from below is vertical and every cause is more active where it is nearest to the effect; but in its generation and origin wind plainly derives from the earth.
ὅτι δ' ἐκ πολλῶν ἀναθυμιάσεων συνιουσῶν κατὰ μικρόν, ὥσπερ αἱ τῶν ποταμῶν ἀρχαὶ γίγνονται νοτιζούσης τῆς γῆς, δῆλον καὶ ἐπὶ τῶν ἔργων ὅθεν γὰρ ἑκάστοτε πνέουσιν, ἐλάχιστοι πάντες εἰσί, προϊόντες δὲ καὶ πόρρω λαμπροὶ πνέουσιν. ἔτι δὲ καὶ τὰ περὶ τὴν ἄρκτον ἐν τῷ χειμῶνι νήνεμα καὶ ἄπνοα, κατ' αὐτὸν ἐκεῖνον τὸν τόπον ἀλλὰ τὸ κατὰ μικρὸν ἀποπνέον καὶ λανθάνον ἔξω προϊὸν ἤδη πνεῦμα γίγνεται λαμπρόν.	196 The facts bear out the view that winds are formed by the gradual union of many evaporations just as rivers derive their sources from the water that oozes from the earth. Every wind is weakest in the spot from which it blows; as they proceed and leave their source at a distance they gather strength. Thus the winter in the north is windless and calm: that is, in the north itself; but, the breeze that blows from there so gently as to escape observation becomes a great wind as it passes on.
τίς μὲν οὖν ἐστιν ἡ τοῦ ἀνέμου φύσις καὶ πῶς γίγνεται, ἔτι δὲ αὐχμῶν τε πέρι καὶ ἐπομβρίας, καὶ διὰ τίν' αἰτίαν καὶ παύονται καὶ γίγνονται μετὰ τοὺς ὄμβρους, διὰ τί τε βορέαι καὶ νότοι πλεῖστοι τῶν ἀνέμων εἰσίν, εἴρηται πρὸς δὲ τούτοις καὶ περὶ τῆς φορᾶς αὐτῶν.	197 We have explained the nature and origin of wind, the occurrence of drought and rains, the reason why rain stops wind and wind rises after rain, the prevalence of north and south winds and also why wind moves in the way it does.

Postquam determinavit de generatione ventorum, hic determinat de motu ipsorum. Et circa hoc duo facit:	188. After determining about the generation of winds, the Philosopher now determines about their movement. About this he does two things:
primo ostendit qualis sit motus eorum; secundo inquirit de principio motus eorum, ibi: propter quod et dubitabit et cetera.	First, he describes their movement, at 188; Secondly, he inquires into the source of their movement, at 189.
Dicit ergo primo quod, quamvis exhalatio quae est principium ventorum, sursum elevetur in rectum, tamen motus eorum non est in rectum: flant enim venti circa terram ab una parte in aliam procedentes, sicut ab oriente in occidentem, vel e converso. Et causa talis motus est quod, ut supra dictum est, superior pars aeris fertur circulariter secundum motum caeli; et licet in illo superiori aere non flant venti, ut supra dictum est, sed in aere inferiori qui est infra altitudinem montium supremorum, tamen iste etiam aer aliquid participat de motu superioris, licet ista circulatio non compleatur. Et ex hoc contingit quod exhalationes commoventes aerem, non movent ipsum in sursum aut in deorsum, quod videtur exigere subtilitas exhalationis calefactae, aut frigiditatis iam condensatae; sed commovent aerem in obliquum, quasi aere retinente aliquid de utroque motu. Unde non oportet quod semper motus venti sit ad occidentem, sicut est motus caeli, sed fit in oppositum exhalationis compellentis; quae tamen impulsio ex motu caeli habet quod sit obliqua.	He says therefore first [194] that although the exhalation which is the principle of winds is lifted on high in a straight line, yet the motion of winds is not in a straight line: for the winds blow around the earth from one direction to the other, as from east to west, or vice versa. The cause of such a course is that, as previously stated, the upper region of air is moved circularly according to the motion of the heaven; and although winds do not blow in that upper air, as stated above, but in the lower air which is below the altitude of the highest mountains, yet this air also participates somewhat in the motion of the higher, although this circling is not completed. From this it comes about that the exhalations moving the air do not move it up or down (which the subtlety of the warmed exhalation or the cold of the condensed seem to demand); rather they move the air obliquely, as though the air were being affected by both motions. Hence, a wind's course need not be always westward, as is the course of the heavens, but in a direction opposite to that of the exhalation impelling it; which impulsion, however, becomes oblique on account of the influence exerted by the movement of the heaven.
Nec propter hoc sequitur quod motus venti non sit naturalis, quia obliquitas eius causatur ex motu corporis caelestis: tum quia motus qui fiunt in inferioribus a corpore caelesti, dicuntur naturales, licet non sint secundum naturam corporis inferioris, ut patet in fluxu et refluxu maris, quia corpora inferiora naturaliter subduntur superioribus; tum quia naturale est unicuique, quod consequitur ipsum ex causa suae generationis; unde, cum causa activa ventorum sit motus solis, ut supra dictum est, sequitur quod obliquitas motus ex motu caeli causata, sit ei naturalis.	However, the fact that its obliqueness is caused by the motion of a heavenly body does not make the wind's motion unnatural. This is so both because motions caused in lower bodies by the heavenly body are called natural, though they may not be according to the nature of the lower body, as is plain in the ebb and flow of the sea — since the lower bodies are by nature subject to the higher, and because whatever results in a thing from the cause of its generation is natural to it. Hence, since the agent cause of winds is the motion of the sun, as was said above, it follows that the obliqueness of the motion, since it is caused by the motion of the heaven, is natural to it.
Deinde cum dicit: propter quod et dubitabit etc., inquirit de principio motus ventorum:	189. Then [195] he inquires about the starting-point of the movement of the winds:
et primo unde incipiant moveri; secundo qualiter ex illo principio procedant, ibi: quod autem exhalationibus et cetera.	First, as to whence they begin their movement, at 189; Secondly, as to how they proceed from that starting-point, at 190.
Dicit ergo primo quod, quia non est motus venti in rectum, scilicet neque sursum neque deorsum, sed in obliquum, dubitabit utique quis unde sit principium motus ventorum, utrum sursum aut deorsum. Sed quod principium motus ventorum sit sursum, manifestat ipse aer, in quo apparet motus venti, antequam ventus flaverit in terra. Nam si apparuerit aliqua nubes aut caligo, videtur moveri a vento iam existente in aere, antequam manifeste veniat circa terram, tanquam vento habente principium motus sursum. Sed quia ventus generatur ex multitudine exhalationis siccae resolutae a terra, manifestum est quod, licet principium motus sit desuper, tamen materiale principium generationis est de subtus. Et hoc ideo, quia ab illo loco incipit motus venti, in quem tendit exhalatio sicca elevata; sicut ab illo loco incipit descendere pluvia, quo ascendit vapor. Et hoc apparet ex hoc quod motus venti magis dominatur in locis altis remotis a terra; et etiam, cum exhalatio in rectum sursum feratur, ibi incipit motus; et in loco ubi appropinquat illi principio, magis potest ventus. Sed tamen manifestum est quod principium generationis venti est ex terra.	He says therefore first [195] that because the course of a wind is not straight up or down, but oblique, someone will wonder whence the starting-point of a wind's movement is, whether from above or below. That the starting-point of the movement of winds is above, is manifested by the air itself, in which the wind's movement appears before the wind blows on earth. For if a cloud or mist is seen in the sky, it is seen to be moved by the wind already present in the air even before it manifestly reached the earth, as a wind having its source of movement from above. But because a wind is generated from the mass of dry exhalation resolved from the earth, it is plain that, although the source of its motion is from above, nevertheless the material principle of its generation is from below. The reason for this is that the motion of a wind originates from that place toward which the elevated dry exhalation tends, just as rain begins to descend from the place whither the vapor has ascended. And this is evident from the fact that the motion of a wind is more vigorous in places high above the earth; moreover, since the exhalation in a straight line is borne upwards, it is from there that the motion originates; and in a place more approaching that beginning, there is more of a chance for wind. However, it is plain that the principle of the generation of a wind is from the earth.
Deinde cum dicit: quod autem exhalationibus etc., ostendit quomodo venti procedunt a suo principio. Et dicit quod sicut principia fluviorum paulatim congregantur ex diversis partibus terrae, ita etiam paulatim ab exhalationibus adunatis congregatur ventus. Et hoc manifestat per duo signa. Quorum unum est, quod venti minimi apparent in locis in quibus oriuntur, sed procedentes fiunt maximi. Aliud signum est, quod in partibus Septentrionalibus, in hieme est tranquillitas, et loca illa sunt sine vento boreali; sed secundum quod receditur ab eis, paulatim crescit ventus, et fit maximus.	190. Then [196] he shows how the winds come forth from their principle. And he says that just as the sources of rivers are collected together little by little from various sectors of the earth, so too a wind is gathered together bit by bit from exhalations that are blended together. And he manifests this with two signs. One of these is that winds appear feeblest in the places in which they arise, but take on strength as they move along. The other sign is that, in northern regions, in winter there is calm and there are no boreal winds there; but as you leave those northern regions, the wind gradually increases and becomes very strong.
Ultimo recolligit quod dictum est: et est manifestum in littera; sed oportet attendere quod eosdem ventos hic notos vocat, quos supra dixit Austros.	Finally he summarizes what has been said — and it is plain in the text at [197]. But it should be noted that the winds which he here calls "Noti" are the ones he above called "austral."

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Lecture 9
On the increase and diminishing of winds

Chapter 5
ὁ δ' ἥλιος καὶ παύει καὶ συνεξορμᾷ τὰ πνεύματα ἀσθενεῖς μὲν γὰρ καὶ ὀλίγας οὔσας τὰς ἀναθυμιάσεις μαραίνει τῷ πλείονι θερμῷ τὸ ἐν τῇ ἀναθυμιάσει ἔλαττον ὄν, καὶ διακρίνει. ἔτι δὲ αὐτὴν τὴν γῆν φθάνει ξηραίνων πρὶν γενέσθαι ἔκκρισιν ἀθρόαν, ὥσπερ εἰς πολὺ πῦρ ἐὰν ὀλίγον ἐμπέσῃ ὑπέκκαυμα, φθάνει πολλάκις πρὶν καπνὸν ποιῆσαι κατακαυθέν. διὰ μὲν οὖν ταύτας τὰς αἰτίας καταπαύει τε τὰ πνεύματα καὶ ἐξ ἀρχῆς γίγνεσθαι κωλύει, τῇ μὲν μαράνσει καταπαύων, τῷ δὲ τάχει τῆς ξηρότητος γίγνεσθαι κωλύων διὸ περὶ Ὠρίωνος ἀνατολὴν μάλιστα γίγνεται νηνεμία, καὶ μέχρι τῶν ἐτησίων καὶ προδρόμων.	198 The sun both checks the formation of winds and stimulates it. When the evaporation is small in amount and faint the sun wastes it and dissipates by its greater heat the lesser heat contained in the evaporation. It also dries up the earth, the source of the evaporation, before the latter has appeared in bulk: just as, when you throw a little fuel into a great fire, it is often burnt up before giving off any smoke. In these ways the sun checks winds and prevents them from rising at all: it checks them by wasting the evaporation, and prevents their rising by drying up the earth quickly. Hence calm is very apt to prevail about the rising of Orion and lasts until the coming of the Etesiae and their 'forerunners'.
ὅλως δὲ γίγνονται αἱ νηνεμίαι διὰ δύ' αἰτίας ἢ γὰρ διὰ ψῦχος ἀποσβεννυμένης τῆς ἀναθυμιάσεως, οἷον ὅταν γένηται πάγος ἰσχυρός, ἢ καταμαραινομένης ὑπὸ τοῦ πνίγους. αἱ δὲ πλεῖσται καὶ ἐν ταῖς ἀνὰ μέσον ὥραις, ἢ τῷ μήπω ἀναθυμιᾶσθαι, ἢ τῷ ἤδη ἐξεληλυθέναι τὴν ἀναθυμίασιν καὶ ἄλλην μήπω ἐπιρρεῖν.	199 Calm is due to two causes. Either cold quenches the evaporation, for instance a sharp frost: or excessive heat wastes it. In the intermediate periods, too, the causes are generally either that the evaporation has not had time to develop or that it has passed away and there is none as yet to replace it.
ἄκριτος δὲ καὶ χαλεπὸς ὁ Ὠρίων εἶναι δοκεῖ, καὶ δύνων καὶ ἐπιτέλλων, διὰ τὸ ἐν μεταβολῇ ὥρας συμβαίνειν τὴν δύσιν καὶ τὴν ἀνατολήν, θέρους ἢ χειμῶνος, καὶ διὰ τὸ μέγεθος τοῦ ἄστρου ἡμερῶν γίγνεται πλῆθος αἱ δὲ μεταβολαὶ πάντων ταραχώδεις διὰ τὴν ἀοριστίαν εἰσίν.	200 Both the setting and the rising of Orion are considered to be treacherous and stormy, because they place at a change of season (namely of summer or winter; and because the size of the constellation makes its rise last over many days) and a state of change is always indefinite and therefore liable to disturbance.
οἱ δ' ἐτησίαι πνέουσι μετὰ τροπὰς καὶ κυνὸς ἐπιτολήν, καὶ οὔτε τηνικαῦτα ὅτε μάλιστα πλησιάζει ὁ ἥλιος, (362a.) οὔτε ὅτε πόρρω καὶ τὰς μὲν ἡμέρας πνέουσι, τὰς δὲ νύκτας παύονται.	201 The Etesiae blow after the summer solstice and the rising of the dog-star: not at the time when the sun is closest nor when it is distant; and they blow by day and cease at night.
αἴτιον δ' ὅτι πλησίον μὲν ὢν φθάνει ξηραίνων πρὶν γενέσθαι τὴν ἀναθυμίασιν ὅταν δ' ἀπέλθῃ μικρόν, σύμμετρος ἤδη γίγνεται ἡ ἀναθυμίασις καὶ ἡ θερμότης, ὥστε τὰ πεπηγότα ὕδατα τήκεσθαι, καὶ τῆς γῆς ξηραινομένης ὑπό τε τῆς οἰκείας θερμότητος καὶ ὑπὸ τῆς τοῦ ἡλίου οἷον τύφεσθαι καὶ θυμιᾶσθαι.	202 The reason is that when the sun is near it dries up the earth before evaporation has taken place, but when it has receded a little its heat and the evaporation are present in the right proportion; so the ice melts and the earth, dried by its own heat and that of the sun, smokes and vapours.
τῆς δὲ νυκτὸς λωφῶσι διὰ τὸ τὰ πεπηγότα τηκόμενα παύεσθαι διὰ τὴν ψυχρότητα τῶν νυκτῶν. θυμιᾶται δ' οὔτε τὸ πεπηγὸς οὔτε τὸ μηδὲν ἔχον ξηρόν, ἀλλ' ὅταν ἔχῃ τὸ ξηρὸν ὑγρότητα, τοῦτο θερμαινόμενον θυμιᾶται.	203 They abate at night because the cold of the nights checks the melting of the ice. What is frozen gives off no evaporation, nor does that which contains no dryness at all: it is only where something dry contains moisture that it gives off evaporation under the influence of heat.
ἀποροῦσι δέ τινες διὰ τί βορέαι μὲν γίγνονται συνεχεῖς, οὓς καλοῦμεν ἐτησίας, μετὰ τὰς θερινὰς τροπάς, νότοι δὲ οὕτως οὐ γίγνονται μετὰ τὰς χειμερινάς.	204 The question is sometimes asked: why do the north winds which we call the Etesiae blow continuously after the summer solstice, when there are no corresponding south winds after the winter solstice?
ἔχει δὲ οὐκ ἀλόγως γίγνονται μὲν γὰρ οἱ καλούμενοι λευκόνοτοι τὴν ἀντικειμένην ὥραν, οὐχ οὕτως δὲ γίγνονται συνεχεῖς διὸ λανθάνοντες ποιοῦσιν ἐπιζητεῖν. αἴτιον δ' ὅτι ὁ μὲν βορέας ἀπὸ τῶν ὑπὸ τὴν ἄρκτον πνεῖ τόπων, οἳ πλήρεις ὕδατος καὶ χιόνος εἰσὶ πολλῆς, ὧν τηκομένων ὑπὸ τοῦ ἡλίου μετὰ τὰς θερινὰς τροπὰς μᾶλλον ἢ ἐν αὐταῖς πνέουσιν οἱ ἐτησίαι οὕτω γὰρ καὶ τὰ πνίγη γίγνεται, οὐχ ὅταν μάλιστα πλησιάζῃ πρὸς ἄρκτον, ἀλλ' ὅταν πλείων μὲν ᾖ χρόνος θερμαίνοντι, ἔτι δὲ ἐγγύς. ὁμοίως δὲ καὶ μετὰ χειμερινὰς τροπὰς πνέουσιν οἱ ὀρνιθίαι καὶ γὰρ οὗτοι ἐτησίαι εἰσὶν ἀσθενεῖς ἐλάττους δὲ καὶ ὀψιαίτεροι τῶν ἐτησίων πνέουσιν βδομηκοστῇ γὰρ ἄρχονται πνεῖν διὰ τὸ πόρρω ὄντα τὸν ἥλιον ἐνισχύειν ἧττον. οὐ συνεχεῖς δ' ὁμοίως πνέουσι, διότι τὰ μὲν ἐπιπολῆς καὶ ἀσθενῆ τότε ἀποκρίνεται, τὰ δὲ μᾶλλον πεπηγότα πλείονος δεῖται θερμότητος. διὸ διαλείποντες οὗτοι πνέουσιν, ἕως ἂν ἐπὶ τροπαῖς πάλιν ταῖς θεριναῖς πνεύσωσιν οἱ ἐτησίαι, ἐπεὶ θέλει γε ὅτι μάλιστα συνεχῶς ἐντεῦθεν ἀεὶ πνεῖν ἄνεμος.	205 The facts are reasonable enough: for the so-called 'white south winds' do blow at the corresponding season, though they are not equally continuous and so escape observation and give rise to this inquiry. The reason for this is that the north wind I from the arctic regions which are full of water and snow. The sun thaws them and so the Etesiae blow: after rather than at the summer solstice. (For the greatest heat is developed not when the sun is nearest to the north, but when its heat has been felt for a considerable period and it has not yet receded far. The 'bird winds' blow in the same way after the winter solstice. They, too, are weak Etesiae, but they blow less and later than the Etesiae. They begin to blow only on the seventieth day because the sun is distant and therefore weaker. They do not blow so continuously because only things on the surface of the earth and offering little resistance evaporate then, the thoroughly frozen parts requiring greater heat to melt them. So they blow intermittently till the true Etesiae come on again at the summer solstice: for from that time onwards the wind tends to blow continuously.)

Postquam philosophus determinavit de generatione et motu ventorum, hic determinat de eorum augmento et deminutione. Et dividitur in partes duas:	191. After determining about the generation and motion of winds, the Philosopher here determines concerning their increase and decrease. And it is divided into two parts:
in prima determinat de deminutione ventorum; in secunda de augmento eorum, ibi: indiscretus autem et difficilis et cetera.	In the first he determines about the decrease of winds, at 191; In the second about their increase, at 193.
Circa primum duo facit:	About the first he does two things:
primo ostendit quomodo sol sit causa deminutionis ventorum; secundo universaliter colligit causas ex quibus contingit ventos cessare vel deminui, ibi: universaliter autem fiunt et cetera.	First, he shows how the sun is the cause of winds' diminishing; Secondly, he collects under one general heading the causes from which
	winds happen to cease or diminish, at 192.
Dicit ergo primo quod, sicut sol movet ventos, ita etiam eos cessare facit. Cum enim sunt paucae exhalationes et debiles, caliditas solis quod est magis calidum in exhalatione distrahit, ipsum consumendo et dissolvendo exhalationes, sicut maior flamma exterminat minorem, consumendo materiam eius: et sic cessant venti. Nec solum facit eos cessare iam existentes, sed etiam impedit eos ne fiant; dum scilicet praevenit, exsiccando terram, congregationem exhalationis, quae est materia ventorum (et hoc contingit maxime temporibus et locis calidis et siccis); ut si quis proiiceret modicum cumbustibile in magnum ignem, ex vehementia ignis desiccatur prius humiditas combustibilis, quam fumus inde exhalare possit.	He says therefore first [198] that just as the sun moves the winds, so also it makes them cease. For when exhalations are few and feeble, the heat of the sun draws out what is more hot in the exhalation, absorbing it and dissolving the exhalations, just as a larger flame destroys a smaller one by consuming its matter. And so the winds cease. Moreover, the sun not only makes them cease when already existing, but also prevents them from being formed: namely, when by drying out the earth it anticipates the massing together of the exhalation, which is the matter of winds (and this happens especially in those seasons and places that are hot and dry). It is as though, if someone should throw a small bit of fuel into a large fire, the strength of the fire were to dry out the moisture in the fuel before smoke could issue forth from it.
Sic igitur sol et cessare facit ventos, consumendo materiam iam recollectam; et impedit ne fiant, velociter desiccando terram. Et ideo circa ortum Orionis, idest ante tempus in quo constellatio Orionis incipit apparere, exiens de sub radiis solis, tempore ferventis aestatis, fit maxima tranquillitas in aere a ventis, usque ad Etesias, idest ad ventos annuales, qui annuatim consueverunt flare in aestate, et prodromos, idest praecursivos: quia Etesias aliquando aliqui venti praecurrunt, propter hoc quod aliquando aliqua materia velocius praeparatur.	Therefore the sun both makes winds to cease by consuming the material already collected, and prevents them from forming by quickly drying out the earth. That is why, around Orion's rising, i.e., before the time when the constellation of Orion begins to appear, coming out from under the sun's rays, during the time of summer's heat, a great calm from the winds prevails in the air, until the "Etesiae," which are the annual winds that are accustomed to blow annually in the summer, and the "prodromes," i.e., the "forerunners" —because certain winds sometimes arrive before the Etesiae, due to suitable matter's being sometimes quickly prepared.
Deinde cum dicit: universaliter autem fiunt etc., colligit causas cessationis ventorum. Et dicit quod tranquillitas a ventis fit propter duas causas: aut propter magnum frigus extinguens caliditatem resolventem exhalationem, sicut accidit tempore quo est magnum gelu, cum supra dictum sit quod pruina impeditur a ventis, et ideo cum est magnum frigus et pruina, non sunt venti; aut etiam accidit propter maximum calorem, qui suffocat et extinguit exhalationem, ut supra dictum est. Sed etiam temporibus intermediis, scilicet inter maximum frigus et maximum calorem, fiunt plurimae tranquillitates: vel quando nondum facta est exhalatio post impedimentum frigoris aut caloris; aut quando iam facta est aliqua exhalatio et praeteriit, et alia nondum advenit, postquam ex praeterita generati sunt venti.	192. Then [199] he brings together the causes of winds' ceasing and says that a calm due to the absence of winds comes about from two causes: either from great cold quenching the warmness that resolves exhalations, as happens at the time of a sharp frost — since it has been said above that frost is prevented by winds, and therefore, when there is great cold and frost, there are no winds; or from excessive heat, which chokes and quenches the exhalation, as was said above. But even in intermediate seasons, i.e., between periods of maximum heat and maximum cold, there are very many calms: either when an exhalation has not yet been formed after heat and cold no longer block them, or when some exhalation has already been formed and has passed, and another has not yet come, after winds have been generated from the one now past.
Deinde cum dicit: indiscretus autem et difficilis etc., determinat de augmento ventorum:	193. Then [200] he determines about the increase of winds.
et primo de augmento quod accidit in ortu Orionis; secundo de augmento quod accidit post ortum canis, ibi: Etesiae autem et cetera.	First, about the increase which accompanies the rising of Orion, at 193; Secondly, about the increase occurring after the rising of the Dog Star, at 194.
Dicit ergo primo quod figuratio Orionis in suo ortu et occasu, idest quando incipit apparere et quando incipit disparere, est indiscreta, sive intolerabilis, et difficilis, idest habet graves et tempestuosos ventos. Nec est contrarium ei quod supra dixit: nam ante ortum Orionis est quaedam tranquillitas, ut supra dixit, sed in ipso ortu et occasu est tempestas. Causa autem huius est, quia ortus ipsius accidit in permutatione aestatis ad autumnum, occasus autem in permutatione autumni ad hiemem. Utrumque autem tempus, et ortus et occasus, per plures dies durat, propter multitudinem constellationis, quae non tota simul incipit apparere vel disparere. In permutationibus autem temporum accidunt multae perturbationes: quia quando tempus non est determinatum ad unum, modo declinat ad hoc, modo ad contrarium. Et ideo multiplicantur pluviae et venti propter exhalationes.	He says therefore first [200] that the configuration of Orion in its rising and setting, i.e., when it begins to appear and when it begins to disappear, is "undiscerning," i.e., intolerable, and "difficult," i.e., has severe and stormy winds. Nor is this contrary to his previous statement, for, before the rising of Orion, there is calm, but in the period of its rising and setting there is stormy weather. The cause of this is that its rising occurs when summer is changing to fall, and its setting when fall is changing to winter. Both times, i.e., that of its rising and that of its setting, cover a number of days because of the constellation's size, which does not appear all at once and disappear all at once. But when seasons are changing, many disturbances occur, for when a season is not determined to one, it inclines now in one direction, now to its contrary. That is why many rains and winds are produced on account of the exhalations.
Deinde cum dicit: Etesiae autem etc., determinat de augmento venti post ortum canis. Et circa hoc tria facit:	194. Then [201] he determines about the increase of wind after the rising of the Dog Star. About this he does three things:
primo proponit propositum; secundo assignat causam, ibi: causa autem etc.; tertio circa praedicta movet dubitationem, ibi: dubitant autem quidam et cetera.	First, he proposes the proposition, at 194; Secondly, he assigns the cause, at 195; Thirdly, he raises a doubt on this point, at 197.
Dicit ergo primo quod Etesiae, idest venti quidam annuales, quasi semper flantes in eodem tempore, flant post conversiones, idest post solstitium aestivale; et non solum statim post ipsum solstitium, sed etiam post ortum caniculae. Et hoc ideo, quia non flant quando sol maxime appropinquat nobis, scilicet in prima versione, scilicet in principio cancri; neque quando est longe, utpote quando est in signis meridionalibus. Et iterum, Etesiae flant diebus, et noctibus cessant.	He says therefore first [201] that the "Etesiae," i.e., certain annual winds, blowing, as it were, always at the same time, blow after the "conversions," i.e., after the summer solstice — and not only right after the solstice, but also after the rising of the Dog Star. This is so because they do not blow when the sun is most close to us, namely, in the first turning [solstice], i.e., in the beginning of Cancer, nor when it is far away, as for example, when it is in the southern signs. Moreover, the Etesiae blow by day but stop at night.
Deinde cum dicit: causa autem etc., assignat causam praedictorum. Et primo, quare de die flant Etesiae, et maxime in mane et circa vesperum: dicens quod quando sol est maxime propinquus, exsiccat humorem, ex quo posset congregari materia venti, si resolvi posset; sed quando aliquantulum recedit, tunc exhalatio resolvitur et fit mediocris; et caliditas etiam est mediocris, ita quod aquae congelatae liquescunt; et terra, dum exsiccatur tum a caliditate solis tum a caliditate intrinseca, quasi turgescit, et dum multiplicatur humiditas resoluta, exhalat; et sic generantur venti.	195. Then [202] he assigns the cause of the aforesaid. First, why it is that the Etesiae blow during the day, and particularly in the morning and around evening. And he says that when the sun is closest, it dries out any moisture from which wind material might be assembled, if it could be resolved; but when it recedes a bit, then an exhalation is resolved in a moderate amount; the heat, likewise, is moderate, so that frozen waters liquefy; and the earth, being dried both by the sun's heat and by its own inherent warmth, begins to swell, as it were, and, as the resolved moisture accumulates, to exhale - and in this way winds are generated.
Secundo ibi: nocte autem deficiunt etc., ostendit causam quare nocte deficiunt Etesiae. Et dicit quod hoc ideo accidit, quia frigiditas noctium congelat humores liquescentes, ut sic exhalatio cesset. Manifestum est enim quod neque id quod est congelatum exhalat, neque siccum non habens humiditatem; sed siccum habens humiditatem calefactum exhalat. Et ideo neque in maxima propinquitate solis flant Etesiae, propter desiccationem; neque in noctibus, propter congelationem. Licet etiam huius possit assignari alia ratio: quia scilicet in nocte sol maxime distat a nobis, et ideo exhalationem elevare non potest.	196. Secondly [203], he shows why the Etesiae abate at night and says that the reason this happens is that the night cold freezes the liquefying humors, so that the exhalation stops. For it is plain that neither does what is frozen exhale, nor what is dry, having no moisture, but the dry which has moisture exhales when heated. Consequently, the Etesiae do not blow either when the sun is nearest us on account of the drying: nor at night, on account of the freezing. However, there is another explanation that could be given, namely, that at night the sun is most distant from us and therefore cannot lift exhalations.
Deinde cum dicit: dubitant autem quidam etc., movet dubitationem circa praedeterminata. Et circa hoc tria facit:	197. Then [204] he raises a doubt about what was just determined. About this he does three things:
primo movet dubitationem; secundo solvit, ibi: habet autem non irrationabiliter etc.; tertio excludit quoddam quod videtur solutioni contrarium, ibi: Auster autem ab aestiva et cetera.	First, he raises the doubt, at 197; Secondly, he solves it, at 198; Thirdly, he dismisses something seemingly contrary to the solution (L. 10).
Dicit ergo primo quod quidam dubitant quare sic venti boreales continue flant post solstitium aestivale, et Noti, idest Austri, non sic flant post solstitium hiemale. Videtur enim quod, sicut post appropinquationem solis ad polum Septentrionalem, flant venti ex illa parte, ita post appropinquationem solis ad polum contrarium, deberent flare venti ex parte opposita.	He says therefore first [204] that some wonder why the north winds blow as they do continuously after the summer solstice, while the "Noti," i.e., the south winds, do not blow the same way after the winter solstice. For it seems that just as after the sun's approach to the north pole, winds blow from there, so after its approach to the opposite pole, winds should blow from the opposite direction.
Deinde cum dicit: habet autem non irrationabiliter etc., solvit praedictam dubitationem. Et dicit quod opposito tempore fiunt quidam venti qui vocantur leuconoti, sic dicti quia in sereno flant (nam leucos in Graeco album significat); sed non sic fiunt continui, sicut Etesiae boreales, et ideo, quia latent, latentia causat praedictam dubitationem. Causa autem quare non flant continue, est ista. Quia Boreas flat a locis qui sunt sub polo Arctico, in quibus est abundantia aquarum et nivium; quae quidem liquefiunt a sole magis post versiones aestivas quam in primis versionibus, licet tunc sol maxime appropinquet nobis; et ideo post aestivas versiones, et non in ipsis versionibus flant Etesiae. Ita etiam maxime suffocationes caliditatum fiunt, non quando sol maxime appropinquat nobis, qui sumus in parte Septentrionali; sed post est maior calor, propter continuationem calefactionis in longo tempore.	198. Then [205] he solves this problem and says that at the corresponding season, winds do blow, called the "leuconoti," so called because they blow in fair weather (leucos in Greek means "white"); but since they do not blow uninterruptedly, as do the Etesiae from the north — and therefore, because latent, it is the fact of their not being noticed that causes the present problem. Now the cause why they do not blow continuously is this: the north wind blows from places under the arctic pole where abound water and snow, which are melted by the sun more after the summer solstice than in the beginning of the turning, although the sun is then closest to us; and that is why it is after and not during the summer solstice that the Etesiae blow. Similarly, the greatest stifling heat occurs, not when the sun is nearest us in the north, but the greater heat comes later, because of the continuing of the warming process over a long time.
Primo enim, quando sol accedit versus tropicum, invenit materiam dispositam: sed paulatim dominando in ipsam, magis imprimit effectum suum postquam incipit recedere, cum tamen adhuc sit prope. Et ideo post ortum canis, in diebus scilicet canicularibus, est maior calor quam ante solstitium vel in ipso solstitio. Et magis etiam tunc liquefiunt et aquae et nives: et ideo tunc plures fiunt exhalationes, et magis flant venti. Sed verum est quod in ipso solstitio, quando est magis prope, magis exsiccat, ut supra dixit, et magis disponit materiam ad exhalationem: sed exhalatio maior fit post ortum canis; et tunc flant Etesiae continue. Et similiter post versiones hiemales flant Ornithiae, dictae ab ave vel gallina: quia oriente aliqua constellatione avis flant, sicut Etesiae post ortum canis (has autem Ornithias supra dixit leuconotos). Et dicit quod Ornithiae sunt debiles, quia sunt minores: et tardius flant quam Etesiae; incipiunt enim flare septuagesimo die post versionem hiemalem, quasi circa principium veris.	For first, when the sun approaches the tropic, it finds matter disposed, then, beginning to dominate it little by little, it imprints its effect more after it begins to recede, but while it is nevertheless still near. That is why after the rising of the Dog Star, i.e., during the dog-days, there is more heat than before the solstice, or during it. Water and snow melt more then also; for which reason more exhalations occur and more winds blow then. But it is true that at the solstice, when the sun is nearer, it causes more drying, as he said above, and disposes the matter more for exhalation; but the greater exhalation occurs after the rising of the Dog Star, and it is then that the Etesiae blow without interruption. And similarly, after the winter solstice the "ornithiae" blow (so called from a bird or hen), because they blow as some constellation of the "Bird" rises, just as the Etesiae blow after the rising of the Dog Star. (The "ornithiae" are the winds he previously called "leuconoti.") And he says that the Ornithiae are weak, because they are minor winds and blow later than the Etesiae: for they begin to blow on the seventieth day after the winter solstice, as though around the beginning of spring.
Et hoc ideo, quia necesse est quod sol multum elongetur et minus invalescat, et non totaliter exurat regionem illam ex qua flant venti Australes, ut possint aliquae exhalationes elevari ad generationem ventorum. Et haec est ratio quare non continue flant: quia quaedam humiditates in superficie terrae existentes et debiles, exhalant ex illa parte terrae, sole sic elongato, ex quibus non potest generari continuus ventus; aliae autem humiditates, quae sunt magis congelatae, indigent maiori caliditate ad hoc quod exhalent; cum scilicet caliditas quam tunc exhibet sol, sit parva, quia sol est distans. Et ideo isti venti non continue, sed interpolate flant, donec iterum post versiones aestivas flaverint Etesiae ex parte Septentrionis: huiusmodi enim venti aquilonares magis habent aptitudinem ut continue flent, propter supradictam causam.	The reason for this is that the sun is more remote and less strong, so that it does not totally heat that region (from which the south winds blow) and enable exhalations to be lifted up to form winds. And the reason why they do not blow continuously is this: certain moistures, that are on the surface of the earth and are weak, exhale from that region of the earth, the sun being at a distance, but from these a continuous wind cannot be generated; the other moistures, being more frozen, need a greater heat, before they vaporize, whereas the heat which the sun then affords is slight, because it is so far away. That is why those winds do not blow continuously, but in fits, until the Etesiae blow again from the north after the summer solstice: for these northern winds are better suited for continuous blowing, for the cause stated above.

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Lecture 10
The south wind not from the antarctic but from the summer tropic

Chapter 5 cont.
ὁ δὲ νότος ἀπὸ τῆς θερινῆς τροπῆς πνεῖ, καὶ οὐκ ἀπὸ τῆς ἑτέρας ἄρκτου.	206 But the south wind blows from the tropic of Cancer and not from the antarctic region.
δύο γὰρ ὄντων τμημάτων τῆς δυνατῆς οἰκεῖσθαι χώρας, τῆς μὲν πρὸς τὸν ἄνω πόλον, καθ' ἡμᾶς, τῆς δὲ πρὸς τὸν ἕτερον καὶ πρὸς μεσημβρίαν, καὶ οὔσης οἷον τυμπάνου (τοιοῦτον γὰρ σχῆμα τῆς γῆς (362b.) ἐκτέμνουσιν αἱ ἐκ τοῦ κέντρου αὐτῆς ἀγόμεναι, καὶ ποιοῦσι δύο κώνους, τὸν μὲν ἔχοντα βάσιν τὸν τροπικόν, τὸν δὲ τὸν διὰ παντὸς φανερόν, τὴν δὲ κορυφὴν ἐπὶ τοῦ μέσου τῆς γῆς τὸν αὐτὸν δὲ τρόπον πρὸς τὸν κάτω πόλον ἕτεροι δύο κῶνοι τῆς γῆς ἐκτμήματα ποιοῦσι. ταῦτα δ' οἰκεῖσθαι μόνα δυνατόν, καὶ οὔτ' ἐπέκεινα τῶν τροπῶν (σκιὰ γὰρ οὐκ ἂν ἦν πρὸς ἄρκτον, νῦν δ' ἀοίκητοι πρότερον γίγνονται οἱ τόποι πρὶν ἢ ὑπολείπειν ἢ μεταβάλλειν τὴν σκιὰν πρὸς μεσημβρίαν) τά θ' ὑπὸ τὴν ἄρκτον ὑπὸ ψύχους ἀοίκητα. φέρεται δὲ καὶ ὁ στέφανος κατὰ τοῦτον τὸν τόπον φαίνεται γὰρ ὑπὲρ κεφαλῆς γιγνόμενος ἡμῖν, ὅταν ᾖ κατὰ τὸν μεσημβρινόν.	207 There are two inhabitable sections of the earth: one near our upper, or nothern pole, the other near the other or southern pole; and their shape is like that of a tambourine. If you draw lines from the centre of the earth they cut out a drum-shaped figure. The lines form two cones; the base of the one is the tropic, of the other the ever visible circle, their vertex is at the centre of the earth. Two other cones towards the south pole give corresponding segments of the earth. These sections alone are habitable. Beyond the tropics no one can live: for there the shade would not fall to the north, whereas the earth is known to be uninhabitable before the sun is in the zenith or the shade is thrown to the south: and the regions below the Bear are uninhabitable because of the cold. (The Crown, too, moves over this region: for it is in the zenith when it is on our meridian.)
διὸ καὶ γελοίως γράφουσι νῦν τὰς περιόδους τῆς γῆς γράφουσι γὰρ κυκλοτερῆ τὴν οἰκουμένην, τοῦτο δ' ἐστὶν ἀδύνατον κατά τε τὰ φαινόμενα καὶ κατὰ τὸν λόγον. ὅ τε γὰρ λόγος δείκνυσιν ὅτι ἐπὶ πλάτος μὲν ὥρισται, τὸ δὲ κύκλῳ συνάπτειν ἐνδέχεται διὰ τὴν κρᾶσιν, —οὐ γὰρ ὑπερβάλλει τὰ καύματα καὶ τὸ ψῦχος κατὰ μῆκος, ἀλλ' ἐπὶ πλάτος, ὥστ' εἰ μή που κωλύει θαλάττης πλῆθος, ἅπαν εἶναι πορεύσιμον, —καὶ κατὰ τὰ φαινόμενα περί τε τοὺς πλοῦς καὶ τὰς πορείας πολὺ γὰρ τὸ μῆκος διαφέρει τοῦ πλάτους.	208 So we see that the way in which they now describe the geography of the earth is ridiculous. They depict the inhabited earth as round, but both ascertained facts and general considerations show this to be impossible. If we reflect we see that the inhabited region is limited in breadth, while the climate admits of its extending all round the earth. For we meet with no excessive heat or cold in the direction of its length but only in that of its breadth; so that there is nothing to prevent our travelling round the earth unless the extent of the sea presents an obstacle anywhere. The records of journeys by sea and land bear this out. They make the length far greater than the breadth.
τὸ γὰρ ἀπὸ Ἡρακλείων στηλῶν μέχρι τῆς Ἰνδικῆς τοῦ ἐξ Αἰθιοπίας πρὸς τὴν Μαιῶτιν καὶ τοὺς ἐσχατεύοντας τῆς Σκυθίας τόπους πλέον ἢ πέντε πρὸς τρία τὸ μέγεθός ἐστιν, ἐάν τέ τις τοὺς πλοῦς λογίζηται καὶ τὰς ὁδούς, ὡς ἐνδέχεται λαμβάνειν τῶν τοιούτων τὰς ἀκριβείας. καίτοι ἐπὶ πλάτος μὲν μέχρι τῶν ἀοικήτων ἴσμεν τὴν οἰκουμένην ἔνθα μὲν γὰρ διὰ ψῦχος οὐκέτι κατοικοῦσιν, ἔνθα δὲ διὰ τὴν ἀλέαν. τὰ δὲ τῆς Ἰνδικῆς ἔξω καὶ τῶν στηλῶν τῶν Ἡρακλείων διὰ τὴν θάλατταν οὐ φαίνεται συνείρειν, τῷ συνεχῶς εἶναι πᾶσαν οἰκουμένην)	If we compute these voyages and journeys the distance from the Pillars of Heracles to India exceeds that from Aethiopia to Maeotis and the northernmost Scythians by a ratio of more than 5 to 3, as far as such matters admit of accurate statement. Yet we know the whole breadth of the region we dwell in up to the uninhabited parts: in one direction no one lives because of the cold, in the other because of the heat. But it is the sea which divides as it seems the parts beyond India from those beyond the Pillars of Heracles and prevents the earth from being inhabited all round.
ἐπεὶ δ' ὁμοίως ἔχειν ἀνάγκη τόπον τινὰ πρὸς τὸν ἕτερον πόλον ὥσπερ ὃν ἡμεῖς οἰκοῦμεν πρὸς τὸν ὑπὲρ ἡμῶν, δῆλον ὡς ἀνάλογον ἕξει τά τ' ἄλλα καὶ τῶν πνευμάτων ἡ στάσις ὥστε καθάπερ ἐνταῦθα βορέας ἐστίν, κἀκείνοις ἀπὸ τῆς ἐκεῖ ἄρκτου τις ἄνεμος οὕτως ὤν, ὃν οὐδὲν δυνατὸν διέχειν δεῦρο, ἐπεὶ οὐδ' ὁ βορέας οὗτος εἰς τὴν ἐνταῦθα (363a.) οἰκουμένην πᾶσάν ἐστιν ἔστιν γὰρ ὥσπερ ἀπόγειον τὸ πνεῦμα τὸ βόρειον [ἕως ὁ βορέας οὗτος εἰς τὴν ἐνταῦθα οἰκουμένην πνεῖ]. ἀλλὰ διὰ τὸ τὴν οἴκησιν κεῖσθαι ταύτην πρὸς ἄρκτον, πλεῖστοι βορέαι πνέουσιν. ὅμως δὲ καὶ ἐνταῦθα ἐλλείπει καὶ οὐ δύναται πόρρω διήκειν, ἐπεὶ περὶ τὴν ἔξω Λιβύης θάλατταν τὴν νοτίαν, ὥσπερ ἐνταῦθα οἱ βορέαι καὶ οἱ νότοι πνέουσιν, οὕτως ἐκεῖ εὖροι καὶ ζέφυροι διαδεχόμενοι συνεχεῖς ἀεὶ πνέουσιν. ὅτι μὲν οὖν ὁ νότος οὐκ ἔστιν ὁ ἀπὸ τοῦ ἑτέρου πόλου πνέων ἄνεμος, δῆλον. ἐπεὶ δ' οὔτ' ἐκεῖνος, οὔτε ὁ ἀπὸ χειμερινῆς τροπῆς (δέοι γὰρ ἂν ἄλλον ἀπὸ θερινῆς εἶναι τροπῆς οὕτως γὰρ τὸ ἀνάλογον ἀποδώσει νῦν δ' οὐκ ἔστιν εἷς γὰρ μόνος φαίνεται πνέων ἐκ τῶν ἐκεῖθεν τόπων) ὥστ' ἀνάγκη τὸν ἀπὸ τοῦ κατακεκαυμένου τόπου πνέοντα ἄνεμον εἶναι νότον. ἐκεῖνος δ' ὁ τόπος διὰ τὴν τοῦ ἡλίου γειτνίασιν οὐκ ἔχει ὕδατα καὶ νομάς, αἳ διὰ τὴν πῆξιν ποιήσουσιν ἐτησίας ἀλλὰ διὰ τὸ τὸν τόπον εἶναι πολὺ πλείω ἐκεῖνον καὶ ἀναπεπταμένον, μείζων καὶ πλείων καὶ μᾶλλον ἀλεεινὸς ἄνεμος ὁ νότος ἐστὶ τοῦ βορέου, καὶ διήκει μᾶλλον δεῦρο ἢ οὗτος ἐκεῖ. τίς μὲν οὖν αἰτία τούτων ἐστὶ τῶν ἀνέμων, καὶ πῶς ἔχουσι πρὸς ἀλλήλους, εἴρηται.	209 Now since there must be a region bearing the same relation to the southern pole as the place we live in bears to our pole, it will clearly correspond in the ordering of its winds as well as in other things. So just as we have a north wind here, they must have a corresponding wind from the antarctic. This wind cannot reach us since our own north wind is like a land breeze and does not even reach the limits of the region we live in. The prevalence of north winds here is due to our lying near the north. Yet even here they give out and fail to penetrate far: in the southern sea beyond Libya east and west winds are always blowing alternately, like north and south winds with us. So it is clear that the south wind is not the wind that blows from the south pole. It is neither that nor the wind from the winter tropic. For symmetry would require another wind blowing from the summer tropic, which there is not, since we know that only one wind blows from that quarter. So the south wind clearly blows from the torrid region. Now the sun is so near to that region that it has no water, or snow which might melt and cause Etesiae. But because that place is far more extensive and open the south wind is greater and stronger and warmer than the north and penetrates farther to the north than the north wind does to the south. The origin of these winds and their relation to one another has now been explained.

Quia in solutione praedictae dubitationis posuerat quod venti Australes non flant continue post hiemales versiones, sicut aquilonares post aestivas; et causa quam assignavit, supponebat quod venti Australes non flarent a locis in quibus abundant aquae et nives; quod esset falsum, si Auster flaret ab altero polo, quia etiam ibi abundat talis materia, ut supra dictum est; ideo nunc intendit ostendere quod Auster non flat ab altero polo, sed a loco qui est sub tropico aestivali. Et circa hoc tria facit:	199. Because in solving the foregoing doubt the Philosopher had posited that the south winds do not blow uninterruptedly after the winter solstice, as do the northern winds after the summer solstice, and because the reason he assigned supposed that southern winds do not blow from regions of much water and snow (which would be false, if the south wind should blow from the other pole, where there is also an abundance of such matter, as has been said above), he therefore now intends to show that the south wind does not blow from the other pole but from a place under the summer tropic. About this he does three things:
primo proponit quod intendit; secundo manifestat dispositionem terrae habitabilis, ut melius accipiatur quod intendit, ibi: duabus enim existentibus etc.; tertio manifestat quod proponit, ibi: quoniam autem similiter et cetera.	First, he proposes what he intends, at 199; Secondly, he outlines the disposition of the habitable earth, to enable one to better understand what he intends, at 200; Thirdly, he manifests what he proposes, at 202.
Dicit ergo primo quod Auster flat nobis ab aestiva versione, idest a loco qui est sub tropico aestivali, scilicet sub cancro; et non ab altera ursa, idest ab altero polo immanifesto nobis. Utitur autem tali modo loquendi, quia polum Arcticum, qui nobis apparet, circumeunt constellationes ursae, maioris scilicet et minoris.	He says therefore first [206] that the south wind blows toward us "from the summer turning," i.e., from the place under the summer tropic, namely, under Cancer, and not "from the other Bear," i.e., from the other pole, concealed from us. He uses this terminology because the arctic pole, which is visible to us, is the one around which the constellations of the Bear, Big and Little, rotate.
Deinde cum dicit: duabus enim existentibus etc., ostendit dispositionem terrae habitabilis.	200. Then [207] he shows the disposition of the habitable earth.
Et primo ostendit quod figura terrae habitabilis est sicut tympani; secundo autem excludit opinionem contrariam quorundam, ibi: propter quod et ridicule et cetera.	First, he shows that the shape of the habitable earth is as a drum, at 200; Secondly, he dismisses a contrary opinion which some held, at 201.
Dicit ergo primo quod duae partes sunt quae possunt habitari: una quidem quae est versus superiorem polum Arcticum, in qua scilicet nos habitamus; altera vero est versus alterum polum, et est nobis ad meridiem, sicut et nostra habitabilis est eis ad meridiem ipsorum. Sed utrum illa terra habitetur, relinquit immanifestum. Utriusque tamen partis est figura ad modum tympani. Cuius imaginationem oportet sic accipere ex eis quae ponit.	He says therefore first [207] that there are two zones that can be inhabited: one toward the upper, arctic, pole, in which we live; the other, toward the opposite pole, south of us, just as our habitable area is south to them. But whether that land is inhabited, he leaves unclarified. The shape, however, of both areas resembles a drum. How this is to be imagined must be gathered from the facts he gives.
Manifestum est enim quod aliqua pars caelestis sphaerae est nobis semper apparens, scilicet a polo Arctico usque ad aliquam quantitatem, quae tanto minor est, quanto ad polum oppositum polo Arctico aliquis magis appropinquat. Alia autem pars est nobis semper immanifesta, scilicet a polo contrario usque ad aliquam quantitatem, quae etiam tanto maior est, quanto est maior propinquitas ad polum Arcticum. In medio autem inter utrumque polum est circulus aequinoctialis, quem intersecat zodiacus, declinans ad utramque partem. Ubi ergo zodiacus maxime declinat ab aequinoctiali versus polum Arcticum, est tropicus aestivalis, idest principium cancri: ubi autem maxime declinat versus polum occultum nobis, est tropicus hiemalis, idest principium Capricorni.	For it is plain that a certain portion of the heavenly sphere is always visible to us, namely, from the arctic pole to a zone which is less and less the closer one gets to the opposite pole. Another portion of the heaven is forever invisible to us, namely, from the opposite pole to a certain amount, whose size increases the closer one gets to the arctic pole. Midway between the two poles is the equinoctial circle [equator] intersected by the Zodiac declining toward each region. Where, therefore, the Zodiac declines most from the equinoctial circle toward the arctic pole is the summer tropic, i.e., the beginning of Cancer; where it declines most toward the pole invisible to us is the winter tropic, i.e., the beginning of Capricorn.
Haec ergo est tertia pars caelestis sphaerae, quae est inter duos tropicos. Duae autem aliae partes considerantur: una scilicet inter tropicum aestivalem et id quod est semper nobis manifestum; alia inter tropicum hiemalem et id quod est nobis occultum de caelo. Et quia tota terra sphaerica est, et in centro caelestis sphaerae locata, necesse est quod sub singulis partibus sphaerae caelestis considerentur singulae partes sphaerae terrestris. In puncto igitur terrae qui est sub polo Arctico, describatur a; in puncto vero qui est sub termino partis semper manifestae, describatur b; in puncto vero qui est sub aestivo tropico, describatur c; in puncto vero qui est sub hiemali tropico, describatur d; in puncto autem qui est sub termino partis semper occultae, describatur e; in puncto autem qui est sub polo Antarctico, describatur f; in puncto autem qui est in centro terrae, describatur z; et producantur rectae lineae a centro terrae, scilicet in b et in c. (Lineae zb et zc) faciunt duos angulos cum linea ducta per superficiem terrae, quos angulos hic conos vocat. Et quia linea ducta per superficiem terrae est curva, eo quod terra est sphaerica, manifestum est quod duae praedictae lineae faciunt figuram tympani, descindentes superficiem terrae in figuram non circularem. Et hoc est, quod dicit: talem enim figuram, idest tympani, terrae habitabilis excidunt duae lineae ductae ex centro ipsius, idest terrae, et faciunt duos conos, idest duos angulos, cum linea ducta per superficiem terrae, hunc quidem habentem basim tropicum, idest existentem in basi in tropico puncto, hunc vero semper manifestum, idest alium angulum apud terminum partis caelestis semper nobis manifestae; verticem autem, idest caput trianguli zbc, cuius basis est bc, faciunt in medio terrae, idest in centro.	This, then, is the third region of the heavenly sphere, namely, the one between-the two tropics. Two other parts are considered: one between the summer tropic and that which is always visible to us, and the one between the winter tropic and that which is hidden to us of the heaven. And because the whole earth is spherical, and located in the center of the heavenly sphere, it is necessary that under each part of the heavenly sphere there be considered individual parts of the terrestrial sphere. Let A mark the terrestrial point under the arctic pole; let B mark the point under the limit of the part always visible to us; let C represent the point under the summer tropic; let D mark the point under the winter tropic, let E represent the point under the limit of the part always hidden; let F mark the point under the antarctic pole, and Z the point in the center of the earth. Now draw straight lines from the center of the earth, Z, to B and to C. [The lines ZB and ZC] form two angles with a line drawn on the surface of the earth, which angles he here calls "cones." Because the line on the surface of the earth is curved — for the earth is spherical — it is plain that the two aforesaid lines [ZB and ZC] produce the figure of a drum, cutting the surface of the earth in a non-circular figure. This is what he [Aristotle] says: "Such a shape," i.e., "that of a drum," for the inhabitable earth, "is cut out by two lines proceeding from the center of it," i.e., of the earth, "and they form two cones," i.e., two angles, with a line traced under the surface of the earth, "the base of one angle being the tropic," i.e., having its base in the tropic point, "and the base of the other, the ever visible," i.e., the other angle is at the limit of the part of the heavens always visible; "the vertex, however," i.e., the top of the triangle ZBC, whose base is BC, "is produced in middle of the earth," i.e., in the center.
Et eodem modo ex alia parte versus inferiorem polum: quia illam partem excidunt duae lineae ductae a centro, scilicet in d et in e.	In the same way, in the other direction, toward the lower pole, two lines cut that part, drawn, namely, from the center to D and E.
Et hae duae partes solae possunt habitari. Nam illa pars quae est inter duos tropicos, videtur inhabitabilis propter immensitatem caloris: eo quod sol pertransit quasi directe super eam, et super summitatem capitis habitantium, si habitaretur. Aliae vero partes, quae sunt sub parte caeli semper manifesta et occulta nobis, prope utrumque polum, sunt inhabitabiles propter immensitatem frigoris ex distantia solis. Et quod illa pars quae est ultra tropicum aestivalem, non habitetur, ostendit quia, si habitaretur, non semper apud omnes homines versus polum Arcticum habitantes umbra fieret versus Septentrionem. Si enim sol aliquando esset inter eos et Septentrionem, fieret aliquando eis umbra ad meridiem, in oppositum scilicet solis; si autem aliqui habitarent ultra tropicum aestivum, prope polum Arcticum, tunc quando sol est in tropico aestivo, esset inter eos et polum Arcticum; unde umbra tunc fieret eis versus meridiem. Sed hoc non invenitur ad loca habitabilia, quod deficiat umbra aut permutetur ad meridiem. Ibi quidem deficit umbra, ubi sol existit super summitates capitum, ut sic in nullam partem umbra fieri possit: ibi autem umbra fit ad meridiem, ubi sol declinat magis ad Septentrionem. Talia autem loca dicit esse inhabitabilia, quia etsi aliqui habitent ibi, propter aliquam contemperantiam aut aquarum aut montium, tamen rarae sunt habitationes et graves.	And these two are the only zones that are habitable. For the zone between the two tropics seems uninhabitable because of the immense heat, as the sun passes, as it were, directly over it and over the tops of the heads of the inhabitants, if it should be inhabited. As for the other two zones, under the part of the heaven always visible and under that always hidden from us, near both poles, these are uninhabitable because of the immense cold, due to distance of the sun. That the zone beyond [i.e., below] the summer tropic is not inhabited, he shows from the fact that, if it were, it would not be true that for all men living toward the arctic pole, shadows fall toward the north. For if the sun should sometimes be between them and the north, a shadow would fall sometimes towards the south. But if anyone lived beyond [below] the summer tropic, toward the arctic pole, then, when the sun is in the summer tropic, it would be between them and the arctic pole; hence a shadow would fall for them toward the south. But it is not found in inhabitable regions either that a shadow disappear or shift to the south. For there is no shadow where the sun is directly overhead, so that no shadow can be produced in any direction, while a shadow falls to the south in places where the sun declines more to the north. And he says that such places are uninhabitable, because even though someone should live there on account of some favorable combination of waters or mountains, yet such dwellings are rare and oppressive.
Sicut autem praedicta loca inhabitabilia sunt propter nimium aestum, ita loca quae sunt sub constellatione ursae, quae quidem pars caeli semper nobis apparet, sunt inhabitabilia propter frigus, causatum ex distantia solis. Similiter ergo pars ista terrae in qua nos habitamus, est inter utrumque circulum, scilicet inter eum qui transit per tropicum aestivalem, et eum qui terminat partem caeli semper nobis manifestam. Et hoc evidenter apparet ex hoc quod constellatio coronae, quae quidem est inter utrumque dictorum circulorum, fit nobis super summitatem capitum, quando fuerit in circulo meridiano, idest in circulo qui transit per polos mundi et per punctum qui est supra caput nostrum.	Just as these places are uninhabitable on account of the excessive heat, so the regions under the constellation of the Bear [which is the part of the heaven always visible to us] are uninhabitable on account of the cold caused by the sun being far away. Hence that part of the earth in which we live is between the two circles, i.e., between the one that passes through the summer tropic and the one which bounds that part of the heaven always visible to us. And this is plainly evident from the fact that the constellation of the Crown, which, indeed, is between both these circles, appears directly over our heads, when it is in the "meridian" circle, i.e., in the circle that passes through the poles of the world and the point directly overhead.
Deinde cum dicit: propter quod et ridicule etc., excludit quorundam falsam opinionem. Et dicit quod per praedicta apparet quod deridendi sunt describentes terram habitatam a nobis quasi circularem: hoc enim apparet impossibile et secundum rationem, et secundum signa apparentia. Ratio enim ostendit quod habitatio terrae determinatur secundum latitudinem, ex una parte ad loca inhabitabilia propter aestum, et ex alia parte inhabitabilia propter frigus. Sed quantum ad longitudinem posset copulari circulus, ut tota pars terrae praedicta undique habitaretur, propter eius temperantiam: non enim invenitur excessus frigoris et caloris secundum distantiam orientis et occidentis, secundum quam longitudo terrae attenditur, sed secundum latitudinem, quae attenditur secundum distantiam Poli ad circulum aequinoctialem; eo quod in superficie maior dimensio vocatur longitudo, minor vero latitudo, ab oriente vero in occidentem designatur totus semicirculus, a polo autem Arctico usque ad aequinoctialem circulum, quarta pars circuli.	201. Then [208] he dismisses a false theory upheld by some. And he says that the foregoing account shows how ridiculous they are who describe the inhabited earth as circular: for such a thing is seen to be impossible, both according to reason and according to evident signs. For reason shows that the inhabited portion of earth is limited to a width, bounded on one side by a zone uninhabitable on account of the heat, and on the other by a zone uninhabitable on account of the cold. But along its length a circle could be joined, in such a way that all the aforesaid area would be inhabited, on account of the temperate climate; for no excess of heat and cold is found in the directions of east and west — according to which the earth's length is measured — but only according to width, which is reckoned according to the distance from the pole to the equinoctial circle [equator], since, on a surface the greater dimension is called the length, and the smaller one the width, and from east to west there is designated a whole semicircle, while from the arctic pole to the equator, a quarter part of a circle.
Rationabiliter etiam distantia orientis et occidentis non diversificat calorem et frigus, quia per hoc non fit maior aut minor appropinquatio ad viam solis, sicut fit per distantiam latitudinis. Unde, nisi alicubi prohiberet multitudo maris, totum esset perambulabile quod est ab occidente in orientem, et iterum ab oriente in occidentem, quia totum videtur esse temperatum. Non tamen invenitur habitatum de terra, nisi secundum quantitatem semicirculi ab oriente in occidentem: ad alium enim semicirculum prohibet accessum nobis multitudo maris. Sic igitur ratio ostendit sufficienter quod superficies terrae habitabilis non est circularis vel sphaerica.	It is reasonable also that a distance to east and west should not cause differences of heat and cold, because this does not produce a greater or lesser approach to the sun's path as is produced by distance in latitude. Hence, if the mass of the sea did not somewhere prevent it, the whole course from west to east, and again from east to west, would be traversable, since the whole appears temperate. However, we find the earth inhabited only in a semicircular zone running from east to west; the extent of the sea preventing our access to the other semicircle. Thus does reasoning sufficiently show that the habitable surface of the earth is not circular or spherical.
Et hoc etiam apparet per signa apparentia circa navigationes et itinera: quia multum differt secundum quantitatem longitudo a latitudine, et sic superficies terrae habitabilis non est sphaerica. Et quod multum differat, patet quia illud quod est a columnis Herculis, quae sunt in ultimis partibus Hispaniae, quasi in ultimo termino occidentis, usque ad Tanaim Indicum, quae est longitudo, plus excedit secundum magnitudinem id quod est ab ultimis terminis Ethiopiae usque ad extrema Scythiae loca, quae est latitudo nostrae habitabilis, quam sit proportio quinque ad tria. Si quis ratiocinetur navigationes et itinera, prout convenit, talium distantiarum accipiet certitudinem.	And this is also made evident from manifest signs based on sea and land journeys: there is a great difference in quantity between longitude and latitude; consequently, the surface area that is habitable is not in the shape of a sphere. That there is such a great difference is plain: for from the Pillars of Hercules, which are at the final confines of Spain, as though at the last border of the west, to the Tanais in India, the distance (which is longitude) exceeds in size the distance from the last borders of Ethiopia to the extreme regions of Scythia (which is the latitude of our habitable earth), by a ratio of more than 5 to 3. If anyone were to analyze sea and land voyages in the proper way, he would have no doubt about these distances.
Sed in hoc differt secundum longitudinem et latitudinem, quia scimus totum illud quod est habitabile de terra secundum latitudinem, esse habitatum usque ad loca inhabitabilia, quae non habitantur vel propter frigus vel propter aestum: sed non est ita de longitudine, quia id quod est circa terminum Indicum ex parte orientis, et quod est circa columnas Herculis ex parte occidentis, non videntur posse copulari adinvicem, ut sit reditus ex alia parte, et sic tota ista portio terrae sit habitabilis continue, quia impeditur accessus propter mare. Unde non est nobis certum, utrum aliqui habitent ibi vel non.	But the habitable earth has the following differences respecting longitude and latitude — for we know that all of the inhabitable area of the earth according to latitude is inhabited up to the uninhabitable areas, which are not inhabited either on account of the cold or on account of the heat; but this is not so of the longitude, because the area around the Indian limit to the east, and that around the Pillars of Hercules to the west, do not seem to be able to be conjoined so as to return in another direction, making the whole of this portion of the earth continuously habitable, because access is forbidden by the sea. That is why we cannot know whether people live there or not.
Deinde cum dicit: quoniam autem similiter etc., ostendit propositum de principio Austri. Et circa hoc tria facit:	202. Then at [209] he proves his proposition about the source of the south wind. About this he does three things:
primo ostendit quod Auster non flat ab altero polo; secundo quod non flat a tropico hiemali, sed aestivo, ibi: quoniam autem neque ille etc.; tertio ostendit causam vehementiae Austri, ibi: ille autem et cetera.	First, he shows that the south wind does not blow from the other pole; Secondly, that it does not blow from the winter tropic, but from the summer tropic, at 203; Thirdly, he accounts for the vehemence of the south wind, at 204.
Dicit ergo primo quod sicut ista pars terrae in qua habitamus, se habet ad polum Arcticum, ita etiam necesse est quod aliqua alia se habeat ad polum oppositum. Unde oportet quod proportionabiliter sit ibi flatus ventorum sicut et hic. Unde sicut flat Boreas a polo Arctico, ita ibi flat aliquis ventus a polo opposito (quem nominat aliam ursam). Sed ille ventus qui flat ab alio polo, non potest pertingere huc: quia Boreas non solum non potest pertingere ad aliam partem terrae habitabilem, sed nec etiam in totam istam habitabilem nostram pertingere potest; est enim Boreas ventus apogeios, quod non multum procedere potest. Sed propter hoc quod ista nostra habitabilis posita est ad arctum, plurimi Boreae flant nobis: sed sicut hic flant plurimi Boreae et Austri, ita et extra mare Libycum, quod est ad Austrum, flant plurimi Euri et Zephyri. Sic igitur manifestum est quod Auster non flat ab alio polo.	He says therefore first [209] that just as the area of the earth in which we live is related to tae arctic pole, so must some other be related to the opposite pole. Hence the blowing of winds in that area must be analogous to their blowing here. Then just as the north wind blows from the arctic pole, so a wind must blow there from the opposite pole (which he calls "the other Bear"). But the wind which blows from the other pole cannot reach to here, because the north wind not only cannot reach the other inhabitable part of the earth, but it cannot even reach all of our habitable area: for the north wind is "apogeious," and cannot advance very far. But since our habitable area is to the north, very many north winds blow upon us; but just as many north and south winds blow here, so beyond the Sea of Libya, which is to the south, blow many east and west winds. Consequently, it is plain that the south wind does not blow from the other pole.
Deinde cum dicit: quoniam autem neque ille etc., ostendit quod non flat a tropico hiemali. Quia si Auster flaret a tropico hiemali, alium oporteret dare ventum qui flaret a tropico aestivali, cum ista duo loca sibi proportionaliter correspondeant. Sed hoc non contingit: solus enim unus ventus flat nobis ex illa parte. Quare necesse est quod Auster sit ventus flans a tropico aestivali, ubi est exusta regio.	203. Then [210] he shows that it does not blow from the winter tropic, because if the south wind blew from the winter tropic, there would have to be another wind blowing from the summer tropic, since those two places proportionately correspond. But this does not happen: for only one wind blows on us from that direction. For this reason it is necessary that the south wind is a wind blowing from the summer tropic, where the region is torrid.
Deinde cum dicit: ille autem etc., quia supra assignaverat causam vehementiae Boreae et Austri, supponendo quod [ from here on by another author ] flant a duobus polis oppositis, secundum aliorum opinionem, quae supra impugnata est; ideo hic ostendit veram causam vehementiae Austri, secundum opinionem propriam.	204. Then [211], because he had previously assigned the cause of the vehemence of the north and south wind by assuming that [ from here on by another author ] they blew from the opposite poles, according to the opinion of others, which he has just assailed, therefore he now gives the true cause of the south wind's vehemence according to his own opinion.
Dicit ergo quod licet in illo loco, idest sub tropico aestivali, non sit multa materia fumans, sicut est circa polum, quia propter vicinantiam solis non sunt ibi multae aquae, neque pascua, idest loca herbosa et humida, ex quibus possint pervenire Etesiae, idest venti continui; tamen ad illum locum, propter eius magnitudinem, congregatur ex diversis regionibus materia Austri; qui propter magnitudinem locorum ex quibus per longum tempus adunata est materia eius in magna abundantia, est ventus magis stabilis et fortis quam Boreas. Et ex consequenti magis durare potest, et pertingere ad locum Boreae, quam Boreas possit pertingere illuc, idest ad locum Austri.	He says, therefore, that, although in that region, i.e., under the summer tropic, there is a scarcity of smoking matter in comparison to the pole, because the nearness of the sun forbids the presence of much water or "pastures," i.e., grassy and moist places from which Etesiae, i.e., continuous winds can arise, yet that region is so vast that it receives from various localities a collection of material suitable for a south wind, which wind is stabler and stronger than the north wind, on account of the size of the places from which its abundant matter has been collecting for a long time. As a consequence, this wind can last longer and reach the place of the north wind, more than the north wind can reach there, i.e., the place of the south wind.

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Continuatio
Ignotus Auctor

Lectio 11

6	6
περὶ δὲ θέσεως αὐτῶν, καὶ τίνες ἐναντίοι τίσι, καὶ ποίους ἅμα πνεῖν ἐνδέχεται καὶ ποίους οὔ, ἔτι δὲ καὶ τίνες καὶ πόσοι τυγχάνουσιν ὄντες, καὶ πρὸς τούτοις περὶ τῶν ἄλλων παθημάτων ὅσα μὴ συμβέβηκεν ἐν τοῖς προβλήμασιν εἰρῆσθαι τοῖς κατὰ μέρος, νῦν λέγωμεν. δεῖ δὲ περὶ τῆς θέσεως ἅμα τοὺς λόγους ἐκ τῆς ὑπογραφῆς θεωρεῖν. γέγραπται μὲν οὖν, τοῦ μᾶλλον εὐσήμως ἔχειν, ὁ τοῦ ὁρίζοντος κύκλος διὸ καὶ στρογγύλος. δεῖ δὲ νοεῖν αὐτοῦ τὸ ἕτερον ἔκτμημα τὸ ὑφ' ἡμῶν οἰκούμενον ἔσται γὰρ κἀκεῖνο διελεῖν τὸν αὐτὸν τρόπον. ὑποκείσθω δὲ πρῶτον μὲν ἐναντία κατὰ τόπον εἶναι τὰ πλεῖστον ἀπέχοντα κατὰ τόπον, ὥσπερ κατ' εἶδος ἐναντία τὰ πλεῖστον ἀπέχοντα κατὰ τὸ εἶδος πλεῖστον δ' ἀπέχει κατὰ τόπον τὰ κείμενα πρὸς ἄλληλα κατὰ διάμετρον.	Let us now explain the position of the winds, their oppositions, which can blow simultaneously with which, and which cannot, their names and number, and any other of their affections that have not been treated in the 'particular questions'. What we say about their position must be followed with the help of the figure. For clearness' sake we have drawn the circle of the horizon, which is round, but it represents the zone in which we live; for that can be divided in the same way. Let us also begin by laying down that those things are locally contrary which are locally most distant from one another, just as things specifically most remote from one another are specific contraries. Now things that face one another from opposite ends of a diameter are locally most distant from one another. (See diagram.)
ἔστω οὖν τὸ μὲν ἐφ' ᾧ Α δυσμὴ ἰσημερινή, (363b.) ἐναντίος δὲ τούτῳ τόπος, ἐφ' οὗ τὸ Β, ἀνατολὴ ἰσημερινή ἄλλη δὲ διάμετρος ταύτην πρὸς ὀρθὴν τέμνουσα, ἧς τὸ ἐφ' οὗ Η ἔστω ἄρκτος τούτῳ δ' ἐναντίον ἐξ ἐναντίας, τὸ ἐφ' οὗ Θ, μεσημβρία τὸ δ' ἐφ' οὗ Ζ ἀνατολὴ θερινή, τὸ δ' ἐφ' ᾧ Ε δυσμὴ θερινή, τὸ δ' ἐφ' οὗ Δ ἀνατολὴ χειμερινή, τὸ δ' ἐφ' οὗ Γ δυσμὴ χειμερινή. ἀπὸ δὲ τοῦ Ζ ἤχθω διάμετρος ἐπὶ τὸ Γ, καὶ ἀπὸ τοῦ Δ ἐπὶ τὸ Ε. ἐπεὶ οὖν τὰ μὲν πλεῖστον ἀπέχοντα κατὰ τόπον ἐναντία κατὰ τόπον, πλεῖστον δ' ἀπέχει τὰ κατὰ διάμετρον, ἀναγκαῖον καὶ τῶν πνευμάτων ταῦτα ἀλλήλοις ἐναντία εἶναι, ὅσα κατὰ διάμετρόν ἐστιν.	Let A be the point where the sun sets at the equinox and B, the point opposite, the place where it rises at the equinox. Let there be another diameter cutting this at right angles, and let the point H on it be the north and its diametrical opposite O the south. Let Z be the rising of the sun at the summer solstice and E its setting at the summer solstice; D its rising at the winter solstice, and G its setting at the winter solstice. Draw a diameter from Z to G from D to E. Then since those things are locally contrary which are most distant from one another in space, and points diametrically opposite are most distant from one another, those winds must necessarily be contrary to one another that blow from opposite ends of a diameter.
καλεῖται δὲ κατὰ τὴν θέσιν τῶν τόπων τὰ πνεύματα ὧδε ζέφυρος μὲν τὸ ἀπὸ τοῦ Α τοῦτο γὰρ δυσμὴ ἰσημερινή. ἐναντίος δὲ τούτῳ ἀπηλιώτης ἀπὸ τοῦ Β τοῦτο γὰρ ἀνατολὴ ἰσημερινή. βορέας δὲ <�καὶ> ἀπαρκτίας ἀπὸ τοῦ Η ἐνταῦθα γὰρ ἡ ἄρκτος. ἐναντίος δὲ τούτῳ νότος ἀπὸ τοῦ Θ μεσημβρία τε γὰρ αὕτη ἀφ' ἧς πνεῖ, καὶ τὸ Θ τῷ Η ἐναντίον κατὰ διάμετρον γάρ. ἀπὸ δὲ τοῦ Ζ καικίας αὕτη γὰρ ἀνατολὴ θερινή. ἐναντίος δ' οὐχ ὁ ἀπὸ τοῦ Ε πνέων, ἀλλ' ὁ ἀπὸ τοῦ Γ λίψ οὗτος γὰρ ἀπὸ δυσμῆς χειμερινῆς, ἐναντίος δὲ τούτῳ (κατὰ διάμετρον γὰρ κεῖται). ἀπὸ δὲ τοῦ Δ εὖρος οὗτος γὰρ ἀπ' ἀνατολῆς χειμερινῆς πνεῖ, γειτνιῶν τῷ νότῳ διὸ καὶ πολλάκις εὐρόνοτοι λέγονται πνεῖν. ἐναντίος δὲ τούτῳ οὐχ ὁ ἀπὸ τοῦ Γ λίψ, ἀλλ' ὁ ἀπὸ τοῦ Ε, ὃν καλοῦσιν οἱ μὲν ἀργέστην; οἱ δ' ὀλυμπίαν, οἱ δὲ σκίρωνα οὗτος γὰρ ἀπὸ δυσμῆς θερινῆς πνεῖ, καὶ κατὰ διάμετρον αὐτῷ κεῖται μόνος. οὗτοι μὲν οὖν οἱ κατὰ διάμετρόν τε κείμενοι ἄνεμοι καὶ οἷς εἰσιν ἐναντίοι ἕτεροι δ' εἰσὶν καθ' οὓς οὐκ ἔστιν ἐναντία πνεύματα.	The names of the winds according to their position are these. Zephyrus is the wind that blows from A, this being the point where the sun sets at the equinox. Its contrary is Apeliotes blowing from B the point where the sun rises at the equinox. The wind blowing from H, the north, is the true north wind, called Aparctias: while Notus blowing from O is its contrary; for this point is the south and O is contrary to H, being diametrically opposite to it. Caecias blows from Z, where the sun rises at the summer solstice. Its contrary is not the wind blowing from E but Lips blowing from G. For Lips blows from the point where the sun sets at the winter solstice and is diametrically opposite to Caecias: so it is its contrary. Eurus blows from D, coming from the point where the sun rises at the winter solstice. It borders on Notus, and so we often find that people speak of 'Euro-Noti'. Its contrary is not Lips blowing from G but the wind that blows from E which some call Argestes, some Olympias, and some Sciron. This blows from the point where the sun sets at the summer solstice, and is the only wind that is diametrically opposite to Eurus. These are the winds that are diametrically opposite to one another and their contraries.
ἀπὸ μὲν γὰρ τοῦ Ι ὃν καλοῦσι θρασκίαν οὗτος γὰρ μέσος ἀργέστου καὶ ἀπαρκτίου ἀπὸ δὲ τοῦ Κ ὃν καλοῦσιν μέσην οὗτος γὰρ μέσος καικίου καὶ ἀπαρκτίου. ἡ δὲ τοῦ ΙΚ διάμετρος βούλεται μὲν κατὰ τὸν διὰ παντὸς εἶναι φαινόμενον, οὐκ ἀκριβοῖ δέ. ἐναντία δὲ τούτοις οὐκ ἔστι τοῖς πνεύμασιν, οὔτε τῷ μέσῃ (ἔπνει γὰρ ἄν τις ἐφ' οὗ τὸ Μ τοῦτο γὰρ κατὰ (364a.) διάμετρον) οὔτε τῷ Ι, τῷ θρασκίᾳ (ἔπνει γὰρ ἂν ἀπὸ τοῦ Ν τοῦτο γὰρ κατὰ διάμετρον τὸ σημεῖον, εἰ μὴ ἀπ' αὐτοῦ καὶ ἐπ' ὀλίγον πνεῖ τις ἄνεμος, ὃν καλοῦσιν οἱ περὶ τὸν τόπον ἐκεῖνον φοινικίαν). τὰ μὲν οὖν κυριώτατα καὶ διωρισμένα πνεύματα ταῦτ' ἐστὶ καὶ τοῦτον τέτακται τὸν τρόπον τοῦ δ' εἶναι πλείους ἀνέμους ἀπὸ τῶν πρὸς ἄρκτον τόπων ἢ τῶν πρὸς μεσημβρίαν αἴτιον τό τε τὴν οἰκουμένην ὑποκεῖσθαι πρὸς τοῦτον τὸν τόπον, καὶ ὅτι πολλῷ πλέον ὕδωρ καὶ χιὼν ἀπωθεῖται εἰς τοῦτο τὸ μέρος διὰ τὸ ἐκεῖνα ὑπὸ τὸν ἥλιον εἶναι καὶ τὴν ἐκείνου φοράν, ὧν τηκομένων εἰς τὴν γῆν καὶ θερμαινομένων ὑπὸ τοῦ ἡλίου καὶ τῆς γῆς ἀναγκαῖον πλείω καὶ ἐπὶ πλείω τόπον γίγνεσθαι τὴν ἀναθυμίασιν διὰ ταύτην τὴν αἰτίαν. ἔστι δὲ τῶν εἰρημένων πνευμάτων βορέας μὲν ὅ τ' ἀπαρκτίας κυριώτατα, καὶ θρασκίας καὶ μέσης ὁ δὲ καικίας κοινὸς ἀπηλιώτου καὶ βορέου νότος δὲ ὅ τε ἰθαγενὴς ὁ ἀπὸ μεσημβρίας καὶ λίψ ἀπηλιώτης δὲ ὅ τε ἀπ' ἀνατολῆς ἰσημερινῆς καὶ ὁ εὖρος ὁ δὲ φοινικίας κοινός ζέφυρος δὲ ὅ τε ἰθαγενὴς καὶ ὁ ἀργέστης καλούμενος. ὅλως δὲ τὰ μὲν βόρεια τούτων καλεῖται, τὰ δὲ νότια προστίθεται δὲ τὰ μὲν ζεφυρικὰ τῷ βορέᾳ (ψυχρότερα γὰρ διὰ τὸ ἀπὸ δυσμῶν πνεῖν), νότῳ δὲ τὰ ἀπηλιωτικά (θερμότερα γὰρ διὰ τὸ ἀπ' ἀνατολῆς πνεῖν). διωρισμένων οὖν τῷ ψυχρῷ καὶ τῷ θερμῷ καὶ ἀλεεινῷ τῶν πνευμάτων οὕτως ἐκάλεσαν. θερμότερα μὲν τὰ ἀπὸ τῆς ἕω τῶν ἀπὸ δυσμῆς, ὅτι πλείω χρόνον ὑπὸ τὸν ἥλιόν ἐστι τὰ ἀπ' ἀνατολῆς τὰ δ' ἀπὸ δυσμῆς ἀπολείπει τε θᾶττον καὶ πλησιάζει τῷ τόπῳ ὀψιαίτερον.	There are other winds which have no contraries. The wind they call Thrascias, which lies between Argestes and Aparctias, blows from I; and the wind called Meses, which lies between Caecias and Aparctias, from K. (The line IK nearly coincides with the ever visible circle, but not quite.) These winds have no contraries. Meses has not, or else there would be a wind blowing from the point M which is diametrically opposite. Thrascias corresponding to the point I has not, for then there would be a wind blowing from N, the point which is diametrically opposite. (But perhaps a local wind which the inhabitants of those parts call Phoenicias blows from that point.) These are the most important and definite winds and these their places. There are more winds from the north than from the south. The reason for this is that the region in which we live lies nearer to the north. Also, much more water and snow is pushed aside into this quarter because the other lies under the sun and its course. When this thaws and soaks into the earth and is exposed to the heat of the sun and the earth it necessarily causes evaporation to rise in greater quantities and over a greater space. Of the winds we have described Aparctias is the north wind in the strict sense. Thrascias and Meses are north winds too. (Caecias is half north and half east.) South are that which blows from due south and Lips. East, the wind from the rising of the sun at the equinox and Eurus. Phoenicias is half south and half east. West, the wind from the true west and that called Argestes. More generally these winds are classified as northerly or southerly. The west winds are counted as northerly, for they blow from the place of sunset and are therefore colder; the east winds as southerly, for they are warmer because they blow from the place of sunrise. So the distinction of cold and hot or warm is the basis for the division of the winds into northerly and southerly. East winds are warmer than west winds because the sun shines on the east longer, whereas it leaves the west sooner and reaches it later.

Postquam philosophus determinavit de motu et causis motus ventorum, hic determinat de positione et contrarietate, et aliis passionibus sive affectibus eorum. Et primo praemittit intentionem suam, dicens quod post determinationem praedictorum dicendum est de positione, idest situ et ordine, ipsorum ventorum, et de contrarietate, scilicet qui sint contrarii inter se, et quos possibile est simul flare et quos impossibile. Considerandum est etiam qui sunt secundum nominis rationem, et quot sunt secundum numerum. Adhuc autem de passionibus et accidentibus, sive de affectibus eorum, quae contingit considerare in particularibus problematibus. Et hunc ordinem oportet manifestare ex descriptione singulari, describendo singulos ventos.

Secundo ibi: describitur quidem igitur etc., prosequitur intentum suum. Et circa hoc tria facit: primo ostendit positionem et ordinem ventorum; secundo determinat de contrarietate eorum, ibi: quoniam igitur plurimum etc.; tertio de accidentibus sive affectibus eorum, ibi: sic autem ordinatis ventis et cetera. Prima iterum in duas: primo praemittit quaedam necessaria ad propositum ostendendum; secundo concludit propositum, ibi: sit igitur in quo a et cetera. Circa primum duo facit: primo praemittit quoddam necessarium ad ostendendam positionem ventorum; secundo quoddam quod est necessarium ad declarandam eorum contrarietatem, ibi: supponatur autem primo quidem et cetera. Dicit ergo primo, quod ex quo oportunum est ordinem ventorum manifestare ex descriptione, ut magis manifesta sint dicenda, describatur horizon, quia horizon est circulus quidam, propter quod etiam est rotundus, decidens caelum scilicet in duo hemisphaeria, et ex consequenti terminans visum nostrum circa terram, quia dividit hemisphaeria, idest partem caeli visam a nobis a parte non visa. Considerandum est autem quod horizontes plures sunt et diversi, secundum diversas partes terrae habitabilis. Non enim est idem horizon habitantibus hic Parisius, et habitantibus Romae. Nam cum terra Parisius sit declivior, et Romae altior, eo quod tota terra est rotunda, qui habitant Parisius non vident eandem partem caeli quam vident Romani, quia terra existens Romae altior occupat visui eorum unam partem, sed tamen in singulis describi possunt venti ordine consequenti.

Deinde cum dicit: supponatur autem primo quidem etc., praemittit quoddam quod est necessarium ad ostendendum qui venti sunt contrarii. Et dicit quod supponere debemus primo, quod contraria secundum locum sunt quae maxime distant secundum locum, sicut contraria secundum speciem, idest formam, dicuntur quae maxime distant secundum formam. Contraria enim sunt quae maxime distant in eodem genere et cetera. Non tamen est intelligendum quod contraria secundum formam distent proprie, idest distantia locali; sed ideo dicuntur maxime distare, quia sunt maxime dissimilia naturaliter. Maxime autem distant secundum locum quae distant secundum diametrum, idest quae sunt extrema unius lineae rectae diametralis, adinvicem contraposita, sicut est illa distantia lineae rectae quae transit per centrum horizontis.

Deinde cum dicit: sit igitur in quo a etc., concludit propositum, distinguens horizonta secundum diversa puncta, in habitudine ad solem orientem et occidentem supra ipsum. Et dicit quod ad evidentiam propositi describatur praedictus circulus horizontis, et ducatur linea per centrum eius ab oriente in occidentem, quae dicitur aequinoctialis, et in una parte eius, scilicet in puncto occidentis, describatur a, in altera vero parte, scilicet in puncto orientis contrario huic, idest occidenti, describatur b. Deinde ducatur alia diametros, idest alia linea recta, transiens per centrum horizontis et dividens praedictam lineam aequinoctialem ad angulos rectos: in cuius capite erit ursa, idest polus Septentrionis, in alio vero capite erit meridies, idest polus meridionalis. In puncto ergo meridionali describatur c, in puncto autem Septentrionali d. Rursus ex parte aestivali orientis, idest a latere orientis ex parte aquilonari (quam vocat oriens aestivalis, quia cum sol est in illa parte orientis, facit aestatem), signetur h, ab alio vero latere orientis (quod vocatur oriens hiemalis, ratione praedicta: quia sol existens in illa parte, scilicet a parte meridionali, facit hiemem), designetur g. Sic etiam ex parte occidentis, a parte aquilonari quae est occidens aestivalis, designetur f, a parte meridionali quae est occidens hiemalis e. Iterum ad latus meridiei, ex parte orientis, describatur I, ex parte vero occidentis k. Sic ex parte Aquilonis: nam ex parte orientis describatur l, ex parte vero occidentis m. Et secundum hunc ordinem disponuntur venti, ut in sequenti figura apparet. (Figura).

Deinde cum dicit: quoniam igitur plurimum etc., ostendit qui venti sint contrarii adinvicem. Et circa hoc duo facit: primo ostendit qui sint contrarii; secundo ut melius hoc intelligatur, determinat de nominatione eorum, ibi: vocantur autem et cetera. Dicit ergo primo quod, ex quo contraria secundum locum sunt quae maxime distant secundum locum, maxime autem secundum locum distant quae sunt in extremis oppositis lineae rectae, ut supra dictum est, illi venti sunt contrarii, qui distant secundum lineam rectam diametralem, quae transit per centrum horizontis. Sciendum tamen est quod venti habent duplicem contrarietatem adinvicem, quarum una est secundum locum, de qua hic loquitur Aristoteles, altera est secundum qualitates activas et passivas, quae attenditur non secundum contrarietatem unius qualitatis tantum, sed utriusque. Et secundum hoc subsolanus, qui oritur in puncto b, et est calidus et siccus, contrariatur Favonio qui oritur in puncto a occidentis, et est frigidus et humidus. Auster autem qui oritur sub puncto c meridiei, est calidus et humidus, et contrariatur Septentrioni qui oritur sub puncto d Aquilonis, et est frigidus et siccus. Similiter Vulturnus qui oritur sub puncto h, et est calidus temperate, siccus autem excellenter (quia remittitur caliditas eius propter propinquitatem ad Septentrionem, et augetur siccitas propter eandem causam), est contrarius Africo qui oritur sub puncto e, et est frigidus temperate et humidus excellenter (quia remittitur frigiditas eius propter propinquitatem ad Austrum, et eadem causa augetur humiditas). Eurus qui oritur sub puncto g, et est calidus excellenter et siccus temperate (quia propter vicinitatem ad Austrum augetur eius caliditas et remittitur siccitas), est contrarius Coro qui oritur in puncto f, et est frigidus excellenter et humidus temperate (quia propter vicinantiam ad Septentrionem augetur eius frigiditas et remittitur humiditas). Et propter eandem causam Austroafricus est calidus temperate et humidus excellenter, et contrariatur Aquiloni, qui est frigidus temperate et siccus excellenter. Sic etiam Euroauster est contrarius circio, quia eadem ratione ille est calidus excellenter et humidus temperate, hic autem frigidus temperate et siccus excellenter. Sic igitur hi omnes perfecte contrariantur hac duplici ratione, scilicet quia flant ex opposito secundum lineam rectam, et quia habent qualitates contrarias. Sciendum etiam est, quod cum in omnibus ventis inveniatur exhalatio sicca mixta cum humida, licet in eis exhalatio sicca praedominetur, ut supra dictum est, secundum diversam proportionem mixtionis praedictarum qualitatum venti magis et minus excedunt in praedictis qualitatibus: quae tamen in eis etiam augentur propter loca in quibus oriuntur, et per quae transeunt.

Deinde cum dicit: vocantur autem etc., determinat de nominatione ventorum, ex quo magis determinate apparet qui venti quibus sunt contrarii. Et dicit quod venti denominantur secundum positionem locorum ex quibus flant: quia Zephyrus dicitur ille qui oritur ab a, scilicet ab occidenti aequinoctiali; et contrarius ei, qui scilicet distat secundum diametrum et flat ab oriente aequinoctiali sub puncto b, dicitur Apeliotes. Primus autem a Latinis dicitur Favonius, secundus autem subsolanus. Boreas autem, qui flat a d ubi est ursa, idest a polo Septentrionis, dicitur aparctias, a nobis autem dicitur Septentrio. Contrarius autem huic, qui flat a c, qui est punctus meridiei, dicitur Auster, a Graecis autem vocatur alio nomine Notus. A g vero, quod est oriens hiemalis, flat Eurus. Contrarius autem ei est, non qui flat ab occidente hiemali, sed qui flat ab occidente aestivali, qui est ei oppositus secundum lineam rectam, et dicitur corus, vel Argestes, vel Olympius, vel Scirona. Ab occidente autem hiemali sub puncto e flat ille qui dicitur a nobis Africus, vel Libs, et contrarius est ei qui oritur sub puncto h ab oriente aestivali, et dicitur Caecias vel alio nomine.

Deinde cum dicit: alii autem sunt etc., determinat de contrarietate ventorum minus principalium. Et dicit quod alii sunt venti minus principales, et manifesti in regione ista, quibus non sunt aliqui contrarii nobis manifesti. Sicut est Thrascias, qui flat a puncto m, et mediat inter Argestem et aparctiam, idest inter Corum et Septentrionem, et a nobis dicitur circius. Et similiter Meses, a nobis dictus Aquilo, qui oritur in puncto l, et est medius inter Caeciam et aparctiam, hoc est inter Vulturnum et Septentrionem. Sed a punctis oppositis, scilicet ab I et a k, nullus apparet nobis sensibiliter flare ventus: vel si flant, illi sunt tenues et modici, et non pertingunt ad nos; sicut est ille qui ab incolis loci dicitur Phoenicias, a nobis vero Euroauster, et etiam ille, qui dicitur Austroafricus: sunt enim modici flatus, et ideo nobis non apparent. Dicit autem quod praedicti venti non habent contrarios, quia contrarietas est principaliter inter quatuor principales, inter alios autem non est nisi participative, quia medium participat naturam extremorum.

Deinde cum dicit: essendi autem plures ventos etc., quia superius Aristoteles supposuerat quod plures venti flant a parte boreali quam a parte Australi, ideo hic ostendit causam huius. Et dicit quod causa quare a locis ad arctum, idest ad Septentrionem, inter polum Arcticum et orientem, flant plures venti quam a parte opposita, scilicet Austri, est quia nostra habitabilis propinquior est isti parti quam illi, et ideo venti qui ibi generantur, magis sentiuntur a nobis quam alii, qui flant a parte opposita. Deinde aliam causam assignat, per quam ostenditur simpliciter quare plures venti generantur hic quam ibi: superior enim ratio hoc ostendebat solum quoad nos. Et est, quia ibi sunt plures aquae et nives propter remotionem a sole, quam in alia parte quae est subiecta soli et eius lationi, qui non permittit aquam ibi congelari. Licet enim ventus generetur ex exhalatione sicca, tamen exhalatio sicca non potest continuari aut condensari in ventum sine humiditate, continuante partes siccae exhalationis. Ad arctum igitur magis elevantur exhalationes siccae, et fiunt plures venti.

Deinde cum dicit: est autem dictorum ventorum etc., ostendit ad maiorem evidentiam praedictorum, qui sint venti boreales et qui Australes. Et dicit quod boreales sunt, qui etiam dicuntur quandoque aparctias et Thrascias, idest Septentrio et circius, qui mediant inter Argestem, idest Corum, et Boream; sed Australes sunt Auster, qui etiam ithagenes dicitur, et Libs: qui flant a meridie. Orientales vero sunt Apeliotes et cetera. Et universaliter Orientales sunt duo qui sunt propinquiores orienti, et tertius ille qui oritur in puncto orientis, qui est medius et communis utrique. Sic Occidentales qui sunt propinquiores occidenti, et communis utrique qui oritur in puncto occidentis: Australes vero propinquiores Austro, et medius inter eos: et boreales, qui sunt viciniores Septentrioni, et qui mediat inter eos, ut patet in praemisso circulo. Notandum est autem quod Aristoteles quandoque nominat, et nominari dicit ab aliis, unum ventum nomine alterius: quia propter magnam vicinitatem quam habet locus in quo oritur unus, ad locum alterius, unus videtur participare naturam et nomen alterius: ut Septentrio dicitur Boreas, et sic de singulis. Ostendit deinde quare extenso nomine omnes venti dicuntur boreales vel Australes; et sumit rationem ex similitudine qualitatum. Venti enim Occidentales, qui vocantur Zephyri, quia coniunguntur Boreae sunt frigidiores: Orientales autem, qui iunguntur Australibus, sunt calidiores; et ideo propter similitudinem harum qualitatum Orientales vocantur Australes, Occidentales autem dicuntur boreales; et sic omnes venti dicuntur boreales aut Australes. Assignat autem causam quare Australes venti sunt calidiores: quia scilicet pluri tempore, idest longiori tempore, stant sub sole; et boreales ex opposito sunt frigidiores, quia minus stant sub sole. Potest etiam assignari alia causa: quia scilicet Australes transeunt per loca calidiora, et ideo continue magis calefiunt, boreales vero per frigidiora, et ideo semper magis fiunt frigidiores.

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Lectio 12

οὕτω δὲ τεταγμένων τῶν ἀνέμων, δῆλον ὅτι ἅμα πνεῖν τοὺς μὲν ἐναντίους οὐχ οἷόν τε (κατὰ διάμετρον γάρ ἅτερος οὖν παύσεται ἀποβιασθείς), τοὺς δὲ μὴ οὕτως κειμένους πρὸς ἀλλήλους οὐδὲν κωλύει, οἷον τὸν Ζ καὶ Δ. διὰ τοῦτο ἅμα πνέουσιν ἐνίοτε ἀμφότεροι οὔριοι, ἐπὶ τὸ αὐτὸ σημεῖον, οὐκ ἐκ ταὐτοῦ οὐδὲ τῷ αὐτῷ πνεύματι. κατὰ δὲ τὰς ὥρας τὰς ἐναντίας οἱ ἐναντίοι μάλιστα πνέουσιν, οἷον περὶ (364b.) ἰσημερίαν τὴν μὲν ἐαρινὴν καικίας καὶ ὅλως τὰ ἐπέκεινα τροπῆς θερινῆς, περὶ δὲ τὴν μετοπωρινὴν λίβες, περὶ δὲ τροπὰς θερινὰς μὲν ζέφυρος, χειμερινὰς δὲ εὖρος. ἐπιπίπτουσι δὲ τοῖς ἄλλοις μάλιστα καὶ παύουσιν ἀπαρκτίαι καὶ θρασκίαι καὶ ἀργέσται διὰ τὸ ἐγγυτάτω γὰρ τὴν ὁρμὴν αὐτῶν εἶναι πολλοί τε καὶ ἰσχυροὶ πνέουσι μάλιστα οὗτοι. διὸ καὶ αἰθριώτατοί εἰσι τῶν ἀνέμων πνέοντες γὰρ ἐγγύθεν μάλιστα ἀποβιαζόμενοί τε τἆλλα πνεύματα παύουσι, καὶ ἀποφυσῶντες τὰ συνιστάμενα νέφη ποιοῦσιν αἰθρίαν, ἂν μὴ ψυχροὶ σφόδρα τύχωσιν ἅμα ὄντες. τότε δὲ οὐκ αἴθριοι ἐὰν γὰρ ὦσι μᾶλλον ψυχροὶ ἢ μεγάλοι, φθάνουσι πηγνύντες ἢ προωθοῦντες. ὁ δὲ καικίας οὐκ αἴθριος, ὅτι ἀνακάμπτει εἰς αὑτόν ὅθεν καὶ λέγεται ἡ παροιμία "ἕλκων ἐφ' αὑτὸν ὥστε καικίας νέφος." αἱ δὲ περιστάσεις γίγνονται αὐτῶν καταπαυομένων εἰς τοὺς ἐχομένους κατὰ τὴν τοῦ ἡλίου μετάστασιν, διὰ τὸ κινεῖσθαι μάλιστα τὸ ἐχόμενον τῆς ἀρχῆς ἡ δὲ ἀρχὴ οὕτω κινεῖται τῶν πνευμάτων ὡς ὁ ἥλιος.

Since this is the distribution of the winds it is clear that contrary winds cannot blow simultaneously. They are diametrically opposite to one another and one of the two must be overpowered and cease. Winds that are not diametrically opposite to one another may blow simultaneously: for instance the winds from Z and from D. Hence it sometimes happens that both of them, though different winds and blowing from different quarters, are favourable to sailors making for the same point. Contrary winds commonly blow at opposite seasons. Thus Caecias and in general the winds north of the summer solstice blow about the time of the spring equinox, but about the autumn equinox Lips; and Zephyrus about the summer solstice, but about the winter solstice Eurus. Aparctias, Thrascias, and Argestes are the winds that fall on others most and stop them. Their source is so close to us that they are greater and stronger than other winds. They bring fair weather most of all winds for the same reason, for, blowing as they do, from close at hand, they overpower the other winds and stop them; they also blow away the clouds that are forming and leave a clear sky—unless they happen to be very cold. Then they do not bring fair weather, but being colder than they are strong they condense the clouds before driving them away. Caecias does not bring fair weather because it returns upon itself. Hence the saying: 'Bringing it on himself as Caecias does clouds. When they cease, winds are succeeded by their neighbours in the direction of the movement of the sun. For an effect is most apt to be produced in the neighbourhood of its cause, and the cause of winds moves with the sun.

οἱ ἐναντίοι δὲ ἢ ταὐτὸ ποιοῦσιν ἢ ἐναντίον, οἷον ὑγροὶ λὶψ καὶ καικίας, ὃν ἑλλησποντίαν ἔνιοι καλοῦσιν, καὶ εὖρος, ὃν ἀπηλιώτην. ξηροὶ δὲ ἀργέστης καὶ εὖρος ἀπ' ἀρχῆς δὲ οὗτος ξηρός, τελευτῶν δὲ ὑδατώδης. νιφετώδης δὲ μέσης καὶ ἀπαρκτίας μάλιστα οὗτοι γὰρ ψυχρότατοι. χαλαζώδεις δὲ ἀπαρκτίας καὶ θρασκίας καὶ ἀργέστης. καυματώδης δὲ νότος καὶ ζέφυρος καὶ εὖρος. νέφεσι δὲ πυκνοῦσι τὸν οὐρανὸν καικίας μὲν σφόδρα, λὶψ δὲ ἀραιοτέροις, καικίας μὲν διά τε τὸ ἀνακάμπτειν πρὸς αὑτὸν καὶ διὰ τὸ κοινὸς εἶναι βορέου καὶ εὔρου, ὥστε διὰ μὲν τὸ ψυχρὸς εἶναι πηγνὺς τὸν ἀτμίζοντα ἀέρα συνίστησι, διὰ δὲ τὸ τῷ τόπῳ ἀπηλιωτικὸς εἶναι ἔχει πολλὴν ὕλην καὶ ἀτμίδα ἣν προωθεῖ. αἴθριοι δὲ ἀπαρκτίας, θρασκίας, ἀργέστης ἡ δ' αἰτία εἴρηται πρότερον. ἀστραπὰς δὲ ποιοῦσιν μάλιστα οὗτοί τε καὶ ὁ μέσης διὰ μὲν γὰρ τὸ ἐγγύθεν πνεῖν ψυχροί εἰσιν, διὰ δὲ τὸ ψυχρὸν ἀστραπὴ γίγνεται ἐκκρίνεται γὰρ συνιόντων τῶν νεφῶν. διὸ καὶ ἔνιοι τῶν αὐτῶν τούτων (365a.) χαλαζώδεις εἰσίν ταχὺ γὰρ πηγνύουσιν. ἐκνεφίαι δὲ γίγνονται μετοπώρου μὲν μάλιστα, εἶτα ἔαρος, καὶ μάλιστα ἀπαρκτίας καὶ θρασκίας καὶ ἀργέστης. αἴτιον δ' ὅτι οἱ ἐκνεφίαι γίγνονται μάλιστα ὅταν τῶν ἄλλων πνεόντων ἐμπίπτωσιν ἕτεροι, οὗτοι δὲ μάλιστα ἐμπίπτουσιν τοῖς ἄλλοις πνέουσιν ἡ δ' αἰτία εἴρηται καὶ τούτου πρότερον. οἱ δ' ἐτησίαι περιίστανται τοῖς μὲν περὶ δυσμὰς οἰκοῦσιν ἐκ τῶν ἀπαρκτίων εἰς θρασκίας καὶ ἀργέστας καὶ ζεφύρους (ὁ γὰρ ἀπαρκτίας... ζέφυρός ἐστιν), ἀρχόμενοι μὲν ἀπὸ τῆς ἄρκτου, τελευτῶντες δ' εἰς τοὺς πόρρω τοῖς δὲ πρὸς ἕω περιίστανται μέχρι τοῦ ἀπηλιώτου. περὶ μὲν οὖν ἀνέμων, τῆς τε ἐξ ἀρχῆς αὐτῶν γενέσεως καὶ οὐσίας καὶ τῶν συμβαινόντων κοινῇ τε παθημάτων καὶ περὶ ἕκαστον, τοσαῦθ' ἡμῖν εἰρήσθω.

Contrary winds have either the same or contrary effects. Thus Lips and Caecias, sometimes called Hellespontias, are both rainy gestes and Eurus are dry: the latter being dry at first and rainy afterwards. Meses and Aparctias are coldest and bring most snow. Aparctias, Thrascias, and Argestes bring hail. Notus, Zephyrus, and Eurus are hot. Caecias covers the sky with heavy clouds, Lips with lighter ones. Caecias does this because it returns upon itself and combines the qualities of Boreas and Eurus. By being cold it condenses and gathers the vaporous air, and because it is easterly it carries with it and drives before it a great quantity of such matter. Aparctias, Thrascias, and Argestes bring fair weather for the reason we have explained before. These winds and Meses are most commonly accompanied by lightning. They are cold because they blow from the north, and lightning is due to cold, being ejected when the clouds contract. Some of these same bring hail with them for the same reason; namely, that they cause a sudden condensation. Hurricanes are commonest in autumn, and next in spring: Aparctias, Thrascias, and Argestes give rise to them most. This is because hurricanes are generally formed when some winds are blowing and others fall on them; and these are the winds which are most apt to fall on others that are blowing; the reason for which, too, we have explained before. The Etesiae veer round: they begin from the north, and become for dwellers in the west Thrasciae, Argestae, and Zephyrus (for Zephyrus belongs to the north). For dwellers in the east they veer round as far as Apeliotes. So much for the winds, their origin and nature and the properties common to them all or peculiar to each.

Deinde cum dicit: sic autem ordinatis ventis etc., determinat de his quae consequuntur ventos. Et circa hoc duo facit: primo determinat de quibusdam accidentibus ventorum; secundo determinat de effectibus eorum, ibi: contrarii autem aut idem et cetera. Circa primum tria facit: primo ostendit qui venti possunt simul flare, et qui non; secundo determinat de incidentia ventorum, ibi: incidunt autem aliis etc.; tertio de gyratione eorum, ibi: gyrationes autem fiunt et cetera. Dicit ergo primo, quod si venti sic disponuntur ut praemissum est, scilicet quod contrarii sunt qui ponuntur ex opposito secundum lineam rectam, palam est quod contrarii non possunt simul flare; quia cum unus flet contra alterum, vel ambo essent aeque fortes, et sic mutuo se impedirent: vel unus eorum esset fortior, et sic totaliter exterminaret ventum debiliorem. Sed illi qui non sunt contrarii, possunt quandoque simul flare: sicut g et e, idest Eurus et Africus, quandoque simul flant et ad eandem partem; sed non omnino ex eodem signo, quia Eurus flat ex signo g, Africus autem a signo e. Neque etiam flant eodem spiritu, idest aequali flatu, sed unus fortiori et alter debiliori, secundum diversitatem materiae et contrarii repellentis. Flant autem venti contrarii non simul, sed secundum diversa tempora et contraria: quia contrariorum contrariae sunt causae, diversa autem tempora sunt contraria secundum qualitates contrarias. Ut exempli gratia Caecias flans ab oriente aestivali, flat frequenter circa aequinoctium vernale, et universaliter ad tropicum aestivum accedente sole: Libs autem flat circa aequinoctium autumnale, declinante sole a praedicto tropico; Zephyrus autem flans ab occidente aequinoctiali, flat circa solstitium, vel conversionem aestivalem: Eurus vero et Apeliotes circa hiemalem.

Deinde cum dicit: incidunt autem etc., determinat consequenter de incidentia ventorum. Dicitur autem ventus incidere alteri, qui flans contra alterum, facit eum cessare. Dicit ergo quod aparctias et Thrascias et Argestes qui boreales dicuntur, maxime incidunt aliis, et faciunt eos cessare. Et ratio est, quia flatus illorum est nobis, qui habitamus sub Septentrione, de prope: et etiam flatus ipsorum est fortis, quia in loco ubi oriuntur tales venti, est multitudo materiae, scilicet ex qua fit exhalatio sicca; unde de facili repellunt ventos debiliores quibus incidunt, et sic frequenter faciunt eos cessare. Et sunt causa serenitatis aeris: quia propter vehementiam flatus propellunt consistentiam nubium eis obviantium. Sed hoc contingit quando non sunt vehementer frigidi: tunc enim non serenant aerem, sed sua frigiditate inspissant et ingrossant vaporem in nubem; sicut exempli gratia Caecias frequenter congregat nubes, et non est omnino serenus: quia non flat omnino lateraliter circa terram sed declinat quasi versus terram, et quando a terra reflectitur, tunc propellit nubes obviantes ad locum suum a quo incepit flare, et ibi eas congregat: quod sic est causa nubium et pluviae. Unde dicitur in proverbio de avaro, quod ad seipsum trahit pecuniam sicut Caecias nubem.

Deinde cum dicit: gyrationes autem fiunt etc., determinat de gyratione ventorum. Vocat autem gyrationem generationem venti propinqui, circumeundo horizontem post cessationem primi. Sicut exempli gratia, quando post cessationem subsolani generatur Eurus, qui est ei propinquus, tunc dicitur gyratio ventorum, quia generatur secundum quendam gyrum. Dicit ergo quod gyrationes ventorum cessantium in habita, idest generationes sequentium qui sunt habiti, idest consequenter se habentes ad praecedentes, fiunt secundum translationem solis; quia sol per accessum ad diversa loca elevat exhalationem siccam, quae est principium ventorum, et ita in illis facit generare ventos, per recessum vero, quia deficit elevatio materiae, facit eos cessare: et quia sol accedit et recedit secundum quendam gyrum, ideo facit gyrationes, hoc est generationes ventorum per gyrum. Igitur quia sol primo elevat exhalationes in tropico aestivali, deinde in solstitio autumnali, postea in tropico hiemali, et deinde in solstitio vernali, sic etiam consequenter venti se habent proportionabiliter et similiter.

Deinde cum dicit: contrarii autem etc., determinat de effectibus ventorum. Et circa hoc duo facit: primo determinat de effectibus primariis; secundo de effectibus secundariis, ibi: nebulosus autem et cetera. Dicit ergo primo quod venti contrarii aliquando faciunt idem, et aliquando contrarium: idem faciunt per accidens, et contraria per se, cum per se effectus contrariorum sint contrarii. Sicut Boreas per se frigefacit, sed per accidens, congregando scilicet calidum, calefacit: frigefaciendo enim cogit calidum congregari in unam aliquam partem, et sic calefacit, ut de visceribus terrae in hieme supradictum est; sed Libs et Caecias humectant. Eurus vero (quem propter propinquitatem ad ventum Orientalem quidam Apeliotem vocant) et Argestes desiccant: sed tamen Eurus in fine fit aquosus propter commixtionem vaporis humidi.

Deinde cum dicit: nebulosus autem etc., agit de effectibus eorum secundariis. Et dicit quod aparctias et Meses sunt factivi nubium, quia sunt frigidissimi: frigidi enim est congregare vaporem et condensare eum in nubem; sed per accidens, propter vehementiam flatus, serenant, propellendo nubes ad partem contrariam. Sed generativi grandinis ut frequentius sunt idem aparctias, idest Boreas, et Thrascias et Argestes, propter frigiditatem vehementem cuius est congelare. Et calefactivi sunt Auster, Zephyrus et Eurus, vel propter caliditatem exhalationis elevatae, vel propter caliditatem regionis per quam feruntur. Quod autem hic dicitur de caliditate ventorum Australium propter caliditatem regionis per quam transeunt, verum est etiam in borealibus: sicut enim Auster est calidus propter caliditatem regionis, ita etiam Boreas, contrarius ei, est frigidus propter frigiditatem regionis in qua oritur, et per quam transit: contrariorum enim effectuum in natura semper causae sunt contrariae. Sed Caecias valde condensat caelum, idest aerem, nubibus, et Libs, contrarius ei, rarius hoc facit; quia Caecias reflexus propellit nubes ad suum locum in quo a principio oritur, et etiam est frigidus: et cum hoc habet multam materiam quam propellit, quia loco est apelioticus, idest prope ventum Apeliotem, ubi sol elevat multam exhalationem. Et aparctias et Thrascias et Argestes serenant propter causam prius dictam, per accidens scilicet, propter vehementiam flatus. Et iidem venti, similiter et Meses, faciunt coruscationes, quia sunt frigidi et flant de prope, idest de partibus Septentrionalibus, quae sunt frigidae; coruscationes enim et fulgura fiunt a frigido: quia frigefaciendo nubes, exhalationem siccam in ipsis conclusam et semiaccensam expellit et exire cogit. Et propter eandem causam quidam istorum sunt factivi grandinis, quia sua frigiditate cito congelant nubem in grandinem.

Deinde cum dicit: Ecnephiae autem fiunt etc., ostendit qui venti magis faciunt Ecnephias. Sciendum est autem quod Ecnephia dupliciter sumi potest. Uno modo et principaliter, inquantum est spiritus quidam fluens ex nubibus cum violentia ad terram: et secundum hunc modum determinabitur de ipsa in tertio huius; alio modo sumitur pro motu sursum aut deorsum cuiuscumque venti, propter violentiam alterius incidentis: et sic de ea hic determinatur. Dicit ergo quod Ecnephiae maxime fiunt in autumno, deinde in vere. Et illos ventos maxime faciunt aparctias et Thrascias et Argestes; quia Ecnephiae maxime fiunt, quando aliqui venti incidunt aliis, propellentes eos ad terram propter vehementiam flatus, ut dictum est: sed hoc faciunt praedicti venti, qui sunt maximi flatus et maxime incidunt aliis, ut supra dictum est. Etesiae autem, idest venti annuales, flant gyrando secundum circulum: quia habitantibus circa occidentem incipiunt a Borea, et procedunt in Thrasciam et in Argestem, et terminantur in Zephyrum, qui est frigidus. Sed circa orientem fiunt gyrationes ab eodem Borea versus occidentem et meridiem, usque ad Apeliotem qui flat ab oriente aequinoctiali. Deinde recapitulat quae dicta sunt, dicens quod tanta a nobis dicta sint de ventis, scilicet de substantia, generatione, et de motu, et de loco ipsorum: adhuc autem de accidentibus communibus, et propriis secundum unumquemque ipsorum.

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Resumption of commentary by Thomas Aquinas (lectio 13-15)

Lectio 13

περὶ δὲ σεισμοῦ καὶ κινήσεως γῆς μετὰ ταῦτα λεκτέον ἡ γὰρ αἰτία τοῦ πάθους ἐχομένη τούτου τοῦ γένους ἐστίν. ἔστι δὲ τὰ παρειλημμένα μέχρι γε τοῦ νῦν χρόνου τρία καὶ παρὰ τριῶν. Ἀναξαγόρας τε γὰρ ὁ Κλαζομένιος καὶ πρότερον Ἀναξιμένης ὁ Μιλήσιος ἀπεφήναντο, καὶ τούτων ὕστερον Δημόκριτος ὁ Ἀβδηρίτης. Ἀναξαγόρας μὲν οὖν φησι τὸν αἰθέρα πεφυκότα φέρεσθαι ἄνω, ἐμπίπτοντα δ' εἰς τὰ κάτω τῆς γῆς καὶ κοῖλα κινεῖν αὐτήν τὰ μὲν γὰρ ἄνω συναληλεῖφθαι διὰ τοὺς ὄμβρους (ἐπεὶ φύσει γε ἅπασαν ὁμοίως εἶναι σομφήν), ὡς ὄντος τοῦ μὲν ἄνω τοῦ δὲ κάτω τῆς ὅλης σφαίρας, καὶ ἄνω μὲν τούτου ὄντος τοῦ μορίου ἐφ' οὗ τυγχάνομεν οἰκοῦντες, κάτω δὲ θατέρου. πρὸς μὲν οὖν ταύτην τὴν αἰτίαν οὐδὲν ἴσως δεῖ λέγειν ὡς λίαν ἁπλῶς εἰρημένην τό τε γὰρ ἄνω καὶ τὸ κάτω νομίζειν οὕτως ἔχειν ὥστε μὴ πρὸς μὲν τὴν γῆν πάντῃ φέρεσθαι τὰ βάρος ἔχοντα τῶν σωμάτων, ἄνω δὲ τὰ κοῦφα καὶ τὸ πῦρ, εὔηθες, καὶ ταῦθ' ὁρῶντας τὸν ὁρίζοντα τὴν οἰκουμένην, ὅσην ἡμεῖς ἴσμεν, ἕτερον ἀεὶ γιγνόμενον μεθισταμένων, ὡς οὔσης κυρτῆς καὶ σφαιροειδοῦς καὶ τὸ λέγειν μὲν ὡς διὰ τὸ μέγεθος ἐπὶ τοῦ ἀέρος μένειν, σείεσθαι δὲ φάσκειν τυπτομένην κάτωθεν ἄνω δι' ὅλης. πρὸς δὲ τούτοις οὐδὲν ἀποδίδωσι τῶν συμβαινόντων περὶ τοὺς σεισμούς οὔτε γὰρ χῶραι οὔτε ὧραι αἱ τυχοῦσαι μετέχουσι τούτου τοῦ πάθους.

We must go on to discuss earthquakes next, for their cause is akin to our last subject. The theories that have been put forward up to the present date are three, and their authors three men, Anaxagoras of Clazomenae, and before him Anaximenes of Miletus, and later Democritus of Abdera. Anaxagoras says that the ether, which naturally moves upwards, is caught in hollows below the earth and so shakes it, for though the earth is really all of it equally porous, its surface is clogged up by rain. This implies that part of the whole sphere is 'above' and part 'below': 'above' being the part on which we live, 'below' the other. This theory is perhaps too primitive to require refutation. It is absurd to think of up and down otherwise than as meaning that heavy bodies move to the earth from every quarter, and light ones, such as fire, away from it; especially as we see that, as far as our knowledge of the earth goes, the horizon always changes with a change in our position, which proves that the earth is convex and spherical. It is absurd, too, to maintain that the earth rests on the air because of its size, and then to say that impact upwards from below shakes it right through. Besides he gives no account of the circumstances attendant on earthquakes: for not every country or every season is subject to them.

(365b.) Δημόκριτος δέ φησι πλήρη τὴν γῆν ὕδατος οὖσαν, καὶ πολὺ δεχομένην ἕτερον ὄμβριον ὕδωρ, ὑπὸ τούτου κινεῖσθαι πλείονός τε γὰρ γιγνομένου διὰ τὸ μὴ δύνασθαι δέχεσθαι τὰς κοιλίας ἀποβιαζόμενον ποιεῖν τὸν σεισμόν, καὶ ξηραινομένην ἕλκουσαν εἰς τοὺς κενοὺς τόπους ἐκ τῶν πληρεστέρων τὸ μεταβάλλον ἐμπῖπτον κινεῖν. Ἀναξιμένης δέ φησιν βρεχομένην τὴν γῆν καὶ ξηραινομένην ῥήγνυσθαι, καὶ ὑπὸ τούτων τῶν ἀπορρηγνυμένων κολωνῶν ἐμπιπτόντων σείεσθαι διὸ καὶ γίγνεσθαι τοὺς σεισμοὺς ἔν τε τοῖς αὐχμοῖς καὶ πάλιν ἐν ταῖς ἐπομβρίαις ἔν τε γὰρ τοῖς αὐχμοῖς, ὥσπερ εἴρηται, ξηραινομένην ῥήγνυσθαι, καὶ ὑπὸ τῶν ὑδάτων ὑπερυγραινομένην διαπίπτειν. ἔδει δὲ τούτου συμβαίνοντος ὑπονοστοῦσαν πολλαχῇ φαίνεσθαι τὴν γῆν. ἔτι δὲ διὰ τίν' αἰτίαν περὶ τόπους τινὰς πολλάκις γίγνεται τοῦτο τὸ πάθος οὐδεμιᾷ διαφέροντας ὑπερβολῇ τοιαύτῃ παρὰ τοὺς ἄλλους; καίτοι ἐχρῆν. ὅλως δὲ τοῖς οὕτως ὑπολαμβάνουσιν ἀναγκαῖον ἧττον ἀεὶ τοὺς σεισμοὺς φάναι γίγνεσθαι, καὶ τέλος παύσασθαί ποτε σειομένην τὸ γὰρ σαττόμενον τοιαύτην ἔχει φύσιν. ὥστ' εἰ τοῦτ' ἀδύνατον, δῆλον ὅτι ἀδύνατον καὶ ταύτην εἶναι τὴν αἰτίαν.

Democritus says that the earth is full of water and that when a quantity of rain-water is added to this an earthquake is the result. The hollows in the earth being unable to admit the excess of water it forces its way in and so causes an earthquake. Or again, the earth as it dries draws the water from the fuller to the emptier parts, and the inrush of the water as it changes its place causes the earthquake. Anaximenes says that the earth breaks up when it grows wet or dry, and earthquakes are due to the fall of these masses as they break away. Hence earthquakes take place in times of drought and again of heavy rain, since, as we have explained, the earth grows dry in time of drought and breaks up, whereas the rain makes it sodden and destroys its cohesion. But if this were the case the earth ought to be found to be sinking in many places. Again, why do earthquakes frequently occur in places which are not excessively subject to drought or rain, as they ought to be on the theory? Besides, on this view, earthquakes ought always to be getting fewer, and should come to an end entirely some day: the notion of contraction by packing together implies this. So this is impossible the theory must be impossible too.

De agitatione autem et motu terre et cetera. Postquam Philosophus determinauit de uentis in aere flantibus, hic determinat de effectibus uentorum. Et primo de terremotu, qui causatur ex uento infra terram generato; secundo de tonitruo, qui causatur ex uento in nubibus, ibi: de coruscatione autem et tonitruo et cetera.

Circa primum duo facit. Primo dicit de quo est intentio. Et dicit quod post uentos dicendum est de motu et agitatione terre. Et rationem ordinis assignat quia causa huius passionis, scilicet terremotus, est habita, id est consequens et proxima, huic generi, scilicet uentorum: quod enim uentum causat in aere, hoc causat infra terram terre agitationem.

Secundo cum dicit, sunt autem tradita, exequitur propositum. Et primo secundum opinionem aliorum; secundo secundum ueritatem, ibi: set quoniam manifestum.

Circa primum duo facit. Primo enumerat opiniones et opinantes. Et dicit quod usque ad tempus suum tres opiniones fuerant de terremotu trium philosophorum, quorum unus fuit Anaxagoras, alius fuit Anaximenes predecessor eius, qui et magister ipsius fuisse dicitur, tercius autem post eos fuit Democritus; et nominat eos a locis unde fuerunt.

Secundo ibi: Anaxagoras quidem igitur etc., prosequitur opiniones. Et primo opinionem Anaxagore; secundo opinionem Democriti, ibi: Democritus autem ait etc.; tercio opinionem Anaximenis, ibi: Anaximenes autem ait et cetera.

Circa primum duo facit. Primo ponit opinionem. Circa quam sciendum est quod Anaxagoras estimauit quod sursum et deorsum distinguerentur in uniuerso secundum positionem hominis, ut scilicet quicquid est in uniuerso supra caput nostrum sit sursum, quicquid autem est uersus pedes nostros totum sit deorsum; et secundum hoc sequitur quod sicut terra est inferior ad unam partem celestis spere, ita sit superior respectu partis opposite.

Quia igitur ether, quem dicebat Anaxagoras ignem ex quo ponebat totum celum consistere, naturaliter fertur sursum, terra autem est sursum respectu alicuius partis celi, sequitur quod ether naturaliter feratur uersus terram. Et ita dicebat quod incidit in concauitates que sunt in inferiori parte terre, et sic ether inclusus in terram mouet ipsam; dicebat enim quod naturaliter tota terra est sompha, id est concaua et spongiosa, set ista concauitas non apparet ita in superiori parte terre, quoniam partes terre superiores concluduntur et non sunt concaue propter ymbres humefacientes terram: manifestum est enim quod propter siccitates fiunt yatus et concauitates in terra, unde propter ymbres huiusmodi concauitates impediuntur. Et hoc idem dicebat Anaxagoras ac si una pars tocius spere mundialis sit inferior, que est uersus pedes nostros, et alia superior, scilicet in qua nos habitamus.

Secundo ibi: ad hanc quidem autem causam, inprobat hanc opinionem quatuor rationibus. Circa quarum primam dicit quod cum ista causa sit simpliciter et irrationabiliter assignata, non esset multum oportunum aliquid contra eam dicere eo quod manifeste continet inconueniens: stultum enim est putare quod sursum et deorsum determinentur sic in uniuerso quod non dicatur esse deorsum respectu tocius uniuersi locus terre, ad quem feruntur grauia, et sursum locus oppositus, ad quem feruntur leuia, cuius contrarium ipse ponit.

Secundam rationem ponit ibi: et hoc uidentes et cetera. Ad cuius intelligenciam considerandum est quod cum Anaxagoras poneret ignem naturaliter ferri ad terram ex alia parte spere uelud sursum cogebatur, eadem ratione ponere quod tota terra naturaliter tenderet uersus celum quasi deorsum; set dicebat hoc impediri propter latitudinem terre, unde non ponebat terram esse sperice figure, set late, ut quasi nataret in aere ad modum quo corpora lata natant in aqua, rotunda uero submerguntur.

Hoc autem dicere stultum est, cum uideamus in tota terra quam nos scimus habitatam quod transeuntibus de loco ad locum semper orizon uariatur, quia semper polus articus uel magis uel minus eleuatur super orizontem, et hoc non esset si terra esset late figure uel concaue, set per hoc ostenditur quod est sperice figure et gibbose ex parte nostra.

Terciam rationem ponit ibi: et dicere quidem. Et dicit quod etiam stultum est dicere quod terra quiescat in aere propter suam magnitudinem, et quod tamen ab ethere agitetur totaliter uersus sursum quasi desubtus percussa: hec enim uidentur esse contraria, quod quiescat et moueatur. Quartam rationem ponit ibi: adhuc autem nullum reddunt. Et dicit quod per hanc causam quam assignant de terremotu non potest assignari ratio eorum que accidunt circa terremotus: non enim omnes regiones nec omnia tempora participant hac passione, quod oporteret si terremotus accideret ex causa predicta.

Deinde cum dicit: Democritus autem ait, ponit opinionem Democriti. Et dicit eum dixisse quod terra intrinsecus erat plena aqua, et tamen ab extrinseco superuenit ei multa alia aqua pluuialis a qua mouetur: dum enim aqua crescit, uoragines que sunt sub terra, quas uentres uocat, non possunt faciliter suscipere aquam superuenientem cum quadam uiolencia, et ex hoc accidit terremotus; et simul etiam aqua superueniens trahit partes terre que propter siccitatem inueniuntur aperte; et sic dum tam aqua quam terra superueniens ex plenis locis tendit in uacua, facit agitationem terre.

Hanc autem opinionem specialiter non reprobat, tum quia eius reprobatio apparet ex hiis que supra dicta sunt de fluminum generatione et fontium, tum etiam quia quantum ad aliquid conuenit cum sequenti opinione.

Deinde cum dicit: Anaximenes autem, ponit opinionem Anaximenis. Et circa hoc duo facit. Primo narrat eam. Et dicit eum dixisse quod terra postquam fuerit compluta desiccatur et rumpitur ita quod apparent quedam aperture, et ab hiis aperturis cadunt quedam frusta inferius a quibus terra concutitur. Et huius signum accipiebat ex hoc quod terremotus fiunt tam in temporibus siccis quam pluuiosis: in siccis quidem quia terra per exsiccationem rumpitur, in pluuiosis autem quia aque humectantes terram faciunt terram decidere inferius; et quantum ad hoc concordabat etiam Democritus.

Secundo ibi: oportebat autem etc., inprobat predictam opinionem tripliciter. Primo quidem quia si ex hac causa accideret terremotus, oporteret quod in multis locis appareret terre subuersio propter partes terre que iam ceciderunt inferius in precedentibus terremotibus.

Secundo ibi: adhuc autem etc., inprobat per hoc quod in quibusdam locis sepe fit terremotus in quibus tamen non apparet excessus talis rupture per differenciam ad alia loca, quod tamen oporteret si hoc quod dictum est esset causa terremotus, quia multiplicatio effectus ex multiplicatione cause procedit.

Tercio ibi: omnino autem etc., inprobat per hoc quod oporteret semper minus et minus fieri terremotus, et tandem omnino aliquando cessaret, quia si partes superiores decidunt inferius, oportet quod quandoque repleant partes inferiores ut non sit ultra decidere; unde si hoc est inpossibile, inpossibile est hoc quod dictum est esse causam terremotus.

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Lectio 14

ἀλλ' ἐπειδὴ φανερὸν ὅτι ἀναγκαῖον καὶ ἀπὸ ὑγροῦ καὶ ἀπὸ ξηροῦ γίγνεσθαι ἀναθυμίασιν, ὥσπερ εἴπομεν ἐν τοῖς πρότερον, ἀνάγκη τούτων ὑπαρχόντων γίγνεσθαι τοὺς σεισμούς. ὑπάρχει γὰρ ἡ γῆ καθ' αὑτὴν μὲν ξηρά, διὰ δὲ τοὺς ὄμβρους ἔχουσα ἐν αὑτῇ νοτίδα πολλήν, ὥσθ' ὑπό τε τοῦ ἡλίου καὶ τοῦ ἐν αὐτῇ πυρὸς θερμαινομένης πολὺ μὲν ἔξω πολὺ δ' ἐντὸς γίγνεσθαι τὸ πνεῦμα καὶ τοῦτο ὁτὲ μὲν συνεχὲς ἔξω ῥεῖ πᾶν, ὁτὲ δ' εἴσω πᾶν, ἐνίοτε δὲ καὶ μερίζεται. εἰ δὴ τοῦτ' ἀδύνατον ἄλλως ἔχειν, τὸ μετὰ τοῦτο σκεπτέον ἂν εἴη ποῖον κινητικώτατον εἴη τῶν σωμάτων ἀνάγκη γὰρ τὸ ἐπὶ πλεῖστόν τε πεφυκὸς ἰέναι καὶ σφοδρότατον μάλιστα τοιοῦτον εἶναι. σφοδρότατον μὲν οὖν ἐξ ἀνάγκης τὸ τάχιστα φερόμενον πλήσσει γὰρ μάλιστα διὰ τὸ τάχος ἐπὶ πλεῖστον δὲ πέφυκε διιέναι τὸ διὰ παντὸς ἰέναι μάλιστα δυνάμενον, τοιοῦτον δὲ τὸ λεπτότατον. ὥστ' εἴπερ ἡ τοῦ (366a.) πνεύματος φύσις τοιαύτη, μάλιστα τῶν σωμάτων τὸ πνεῦμα κινητικόν καὶ γὰρ τὸ πῦρ ὅταν μετὰ πνεύματος ᾖ, γίγνεται φλὸξ καὶ φέρεται ταχέως. οὐκ ἂν οὖν ὕδωρ οὐδὲ γῆ αἴτιον εἴη, ἀλλὰ πνεῦμα τῆς κινήσεως, ὅταν εἴσω τύχῃ ῥυὲν τὸ ἔξω ἀναθυμιώμενον. διὸ γίγνονται νηνεμίας οἱ πλεῖστοι καὶ μέγιστοι τῶν σεισμῶν συνεχὴς γὰρ οὖσα ἡ ἀναθυμίασις ἀκολουθεῖ ὡς ἐπὶ τὸ πολὺ τῇ ὁρμῇ τῆς ἀρχῆς, ὥστε ἢ ἔσω ἅμα ἢ ἔξω ὁρμᾷ πᾶσα. τὸ δ' ἐνίους γίγνεσθαι καὶ πνεύματος ὄντος οὐδὲν ἄλογον ὁρῶμεν γὰρ ἐνίοτε ἅμα πλείους πνέοντας ἀνέμους, ὧν ὅταν εἰς τὴν γῆν ὁρμήσῃ θάτερον, ἔσται πνεύματος ὄντος ὁ σεισμός. ἐλάττους δ' οὗτοι τὸ μέγεθος γίγνονται διὰ τὸ διῃρῆσθαι τὴν ἀρχὴν καὶ τὴν αἰτίαν αὐτῶν.	We have already shown that wet and dry must both give rise to an evaporation: earthquakes are a necessary consequence of this fact. The earth is essentially dry, but rain fills it with moisture. Then the sun and its own fire warm it and give rise to a quantity of wind both outside and inside it. This wind sometimes flows outwards in a single body, sometimes inwards, and sometimes it is divided. All these are necessary laws. Next we must find out what body has the greatest motive force. This will certainly be the body that naturally moves farthest and is most violent. Now that which has the most rapid motion is necessarily the most violent; for its swiftness gives its impact the greatest force. Again, the rarest body, that which can most readily pass through every other body, is that which naturally moves farthest. Wind satisfies these conditions in the highest degree (fire only becomes flame and moves rapidly when wind accompanies it): so that not water nor earth is the cause of earthquakes but wind—that is, the inrush of the external evaporation into the earth. Hence, since the evaporation generally follows in a continuous body in the direction in which it first started, and either all of it flows inwards or all outwards, most earthquakes and the greatest are accompanied by calm. It is true that some take place when a wind is blowing, but this presents no difficulty. We sometimes find several winds blowing simultaneously. If one of these enters the earth we get an earthquake attended by wind. Only these earthquakes are less severe because their source and cause is divided.
νυκτὸς δ' οἱ πλείους καὶ μείζους γίγνονται τῶν σεισμῶν, οἱ δὲ τῆς ἡμέρας περὶ μεσημβρίαν νηνεμώτατον γάρ ἐστιν ὡς ἐπὶ τὸ πολὺ τῆς ἡμέρας ἡ μεσημβρία (ὁ γὰρ ἥλιος ὅταν μάλιστα κρατῇ, κατακλείει τὴν ἀναθυμίασιν εἰς τὴν γῆν κρατεῖ δὲ μάλιστα περὶ τὴν μεσημβρίαν), καὶ αἱ νύκτες δὲ τῶν ἡμερῶν νηνεμώτεραι διὰ τὴν ἀπουσίαν τὴν τοῦ ἡλίου ὥστ' ἔσω γίγνεται πάλιν ἡ ῥύσις, ὥσπερ ἄμπωτις, εἰς τοὐναντίον τῆς ἔξω πλημμυρίδος, καὶ πρὸς ὄρθρον μάλιστα τηνικαῦτα γὰρ καὶ τὰ πνεύματα πέφυκεν ἄρχεσθαι πνεῖν. ἐὰν οὖν εἴσω τύχῃ μεταβάλλουσα ἡ ἀρχὴ αὐτῶν ὥσπερ Εὔριπος, διὰ τὸ πλῆθος ἰσχυρότερον ποιεῖ τὸν σεισμόν.	Again, most earthquakes and the severest occur at night or, if by day, about noon, that being generally the calmest part of the day. For when the sun exerts its full power (as it does about noon) it shuts the evaporation into the earth. Night, too, is calmer than day. The absence of the sun makes the evaporation return into the earth like a sort of ebb tide, corresponding to the outward flow; especially towards dawn, for the winds, as a rule, begin to blow then, and if their source changes about like the Euripus and flows inwards the quantity of wind in the earth is greater and a more violent earthquake results.
ἔτι δὲ περὶ τόπους τοιούτους οἱ ἰσχυρότατοι γίγνονται τῶν σεισμῶν, ὅπου θάλαττα ῥοώδης ἢ ἡ χώρα σομφὴ καὶ ὕπαντρος διὸ καὶ περὶ Ἑλλήσποντον καὶ περὶ Ἀχαΐαν καὶ Σικελίαν, καὶ τῆς Εὐβοίας περὶ τούτους τοὺς τόπους δοκεῖ γὰρ διαυλωνίζειν ὑπὸ τὴν γῆν ἡ θάλαττα διὸ καὶ τὰ θερμὰ τὰ περὶ Αἰδηψὸν ἀπὸ τοιαύτης αἰτίας γέγονε. περὶ δὲ τοὺς εἰρημένους τόπους οἱ σεισμοὶ γίγνονται μάλιστα διὰ τὴν στενότητα τὸ γὰρ πνεῦμα γιγνόμενον σφοδρὸν καὶ διὰ τὸ πλῆθος τῆς θαλάττης πολλῆς προσφερομένης ἀπωθεῖται πάλιν εἰς τὴν γῆν, τὸ πεφυκὸς ἀποπνεῖν ἐκ τῆς γῆς. αἵ τε χῶραι ὅσαι (366b.) σομφοὺς ἔχουσι τοὺς κάτω τόπους, πολὺ δεχόμεναι πνεῦμα σείονται μᾶλλον.	The severest earthquakes take place where the sea is full of currents or the earth spongy and cavernous: so they occur near the Hellespont and in Achaea and Sicily, and those parts of Euboea which correspond to our description—where the sea is supposed to flow in channels below the earth. The hot springs, too, near Aedepsus are due to a cause of this kind. It is the confined character of these places that makes them so liable to earthquakes. A great and therefore violent wind is developed, which would naturally blow away from the earth: but the onrush of the sea in a great mass thrusts it back into the earth. The countries that are spongy below the surface are exposed to earthquakes because they have room for so much wind.
καὶ ἔαρος δὲ καὶ μετοπώρου μάλιστα καὶ ἐν ἐπομβρίαις καὶ ἐν αὐχμοῖς γίγνονται διὰ τὴν αὐτὴν αἰτίαν αἵ τε γὰρ ὧραι αὗται πνευματωδέσταται τὸ γὰρ θέρος καὶ ὁ χειμών, τὸ μὲν διὰ τὸν πάγον, τὸ δὲ διὰ τὴν ἀλέαν ποιεῖ τὴν ἀκινησίαν τὸ μὲν γὰρ ἄγαν ψυχρόν, τὸ δ' ἄγαν ξηρόν ἐστι καὶ ἐν μὲν τοῖς αὐχμοῖς πνευματώδης ὁ ἀήρ τοῦτο γὰρ αὐτό ἐστιν ὁ αὐχμός, ὅταν πλείων ἡ ἀναθυμίασις ἡ ξηρὰ γίγνηται τῆς ὑγρᾶς ἐν δὲ ταῖς ὑπερομβρίαις πλείω τε ποιεῖ τὴν ἐντὸς ἀναθυμίασιν, καὶ τῷ ἐναπολαμβάνεσθαι ἐν στενοτέροις τόποις καὶ ἀποβιάζεσθαι εἰς ἐλάττω τόπον τὴν τοιαύτην ἀπόκρισιν, πληρουμένων τῶν κοιλιῶν ὕδατος, ὅταν ἄρξηται κρατεῖν διὰ τὸ πολὺ εἰς ὀλίγον πιληθῆναι τόπον, ἰσχυρῶς κινεῖ ῥέων ὁ ἄνεμος καὶ προσπίπτων δεῖ γὰρ νοεῖν ὅτι ὥσπερ ἐν τῷ σώματι ἡμῶν καὶ τρόμων καὶ σφυγμῶν αἴτιόν ἐστιν ἡ τοῦ πνεύματος ἐναπολαμβανομένη δύναμις, οὕτω καὶ ἐν τῇ γῇ τὸ πνεῦμα παραπλήσιον ποιεῖν, καὶ τὸν μὲν τῶν σεισμῶν οἷον τρόμον εἶναι τὸν δ' οἷον σφυγμόν, καὶ καθάπερ συμβαίνει πολλάκις μετὰ τὴν οὔρησιν (διὰ τοῦ σώματος γὰρ γίγνεται ὥσπερ τρόμος τις ἀντιμεθισταμένου τοῦ πνεύματος ἔξωθεν εἴσω ἀθρόου), τοιαῦτα [γὰρ] γίγνεσθαι καὶ περὶ τὴν γῆν.	For the same reason earthquakes usually take place in spring and autumn and in times of wet and of drought—because these are the windiest seasons. Summer with its heat and winter with its frost cause calm: winter is too cold, summer too dry for winds to form. In time of drought the air is full of wind; drought is just the predominance of the dry over the moist evaporation. Again, excessive rain causes more of the evaporation to form in the earth. Then this secretion is shut up in a narrow compass and forced into a smaller space by the water that fills the cavities. Thus a great wind is compressed into a smaller space and so gets the upper hand, and then breaks out and beats against the earth and shakes it violently. We must suppose the action of the wind in the earth to be analogous to the tremors and throbbings caused in us by the force of the wind contained in our bodies. Thus some earthquakes are a sort of tremor, others a sort of throbbing. Again, we must think of an earthquake as something like the tremor that often runs through the body after passing water as the wind returns inwards from without in one volume.
ὅσην δ' ἔχει τὸ πνεῦμα δύναμιν, οὐ μόνον ἐκ τῶν ἐν τῷ ἀέρι δεῖ θεωρεῖν γιγνομένων (ἐνταῦθα μὲν γὰρ διὰ τὸ μέγεθος ὑπολάβοι τις ἂν τοιαῦτα δύνασθαι ποιεῖν) ἀλλὰ καὶ ἐν τοῖς σώμασι τοῖς τῶν ζῴων οἵ τε γὰρ τέτανοι καὶ οἱ σπασμοὶ πνεύματος μέν εἰσιν κινήσεις, τοσαύτην δὲ ἔχουσιν ἰσχὺν ὥστε πολλοὺς ἅμα πειρωμένους ἀποβιάζεσθαι μὴ δύνασθαι κρατεῖν τῆς κινήσεως τῶν ἀρρωστούντων. τοιοῦτον δὴ δεῖ νοεῖν τὸ γιγνόμενον καὶ ἐν τῇ γῇ, ὡς εἰκάσαι πρὸς μικρὸν μεῖζον. σημεῖα δὲ τούτων καὶ πρὸς τὴν ἡμετέραν αἴσθησιν πολλαχῇ γέγονεν ἤδη γὰρ σεισμὸς ἐν τόποις τισὶν γιγνόμενος οὐ πρότερον ἔληξε πρὶν ἐκρήξας εἰς τὸν ὑπὲρ τῆς γῆς τόπον φανερῶς ὥσπερ ἐκνεφίας ἐξῆλθεν ὁ κινήσας ἄνεμος, (367a.) οἷον καὶ περὶ Ἡράκλειαν ἐγένετο τὴν ἐν τῷ Πόντῳ νεωστί, καὶ πρότερον περὶ τὴν Ἱερὰν νῆσον (αὕτη δ' ἐστὶν μία τῶν Αἰόλου καλουμένων νήσων) ἐν ταύτῃ γὰρ ἀνῴδει τι τῆς γῆς, καὶ ἀνῄει οἷον λοφώδης ὄγκος μετὰ ψόφου τέλος δὲ ῥαγέντος ἐξῆλθεν πνεῦμα πολὺ καὶ τὸν φέψαλον καὶ τὴν τέφραν ἀνῆκεν καὶ τήν τε Λιπαραίων πόλιν οὖσαν οὐ πόρρω πᾶσαν κατετέφρωσε καὶ εἰς ἐνίας τῶν ἐν Ἰταλίᾳ πόλεων ἦλθεν καὶ νῦν ὅπου τὸ ἀναφύσημα τοῦτο ἐγένετο, δῆλόν ἐστιν.	The force wind can have may be gathered not only from what happens in the air (where one might suppose that it owed its power to produce such effects to its volume), but also from what is observed in animal bodies. Tetanus and spasms are motions of wind, and their force is such that the united efforts of many men do not succeed in overcoming the movements of the patients. We must suppose, then (to compare great things with small), that what happens in the earth is just like that. Our theory has been verified by actual observation in many places. It has been known to happen that an earthquake has continued until the wind that caused it burst through the earth into the air and appeared visibly like a hurricane. This happened lately near Heracleia in Pontus and some time past at the island Hiera, one of the group called the Aeolian islands. Here a portion of the earth swelled up and a lump like a mound rose with a noise: finally it burst, and a great wind came out of it and threw up live cinders and ashes which buried the neighbouring town of Lipara and reached some of the towns in Italy. The spot where this eruption occurred is still to be seen.
καὶ γὰρ δὴ τοῦ γιγνομένου πυρὸς ἐν τῇ γῇ ταύτην οἰητέον εἶναι τὴν αἰτίαν, ὅταν κοπτόμενον ἐκπρησθῇ πρῶτον εἰς μικρὰ κερματισθέντος τοῦ ἀέρος.	Indeed, this must be recognized as the cause of the fire that is generated in the earth: the air is first broken up in small particles and then the wind is beaten about and so catches fire.
τεκμήριον δ' ἐστὶ τοῦ ῥεῖν ὑπὸ γῆν τὰ πνεύματα καὶ τὸ γιγνόμενον περὶ ταύτας τὰς νήσους ὅταν γὰρ ἄνεμος μέλλῃ πνευσεῖσθαι νότος, προσημαίνει πρότερον ἠχοῦσι γὰρ οἱ τόποι ἐξ ὧν γίγνεται τὰ ἀναφυσήματα, διὰ τὸ τὴν θάλατταν μὲν προωθεῖσθαι ἤδη πόρρωθεν, ὑπὸ δὲ ταύτης τὸ ἐκ τῆς γῆς ἀναφυσώμενον ἀπωθεῖσθαι πάλιν εἴσω, ᾗπερ ἐπέρχεται ἡ θάλαττα ταύτῃ. ποιεῖ δὲ ψόφον ἄνευ σεισμοῦ διά τε τὴν εὐρυχωρίαν τῶν τόπων (ὑπερχεῖται γὰρ εἰς τὸ ἀχανὲς ἔξω) καὶ δι' ὀλιγότητα τοῦ ἀπωθουμένου ἀέρος.	A phenomenon in these islands affords further evidence of the fact that winds move below the surface of the earth. When a south wind is going to blow there is a premonitory indication: a sound is heard in the places from which the eruptions issue. This is because the sea is being pushed on from a distance and its advance thrusts back into the earth the wind that was issuing from it. The reason why there is a noise and no earthquake is that the underground spaces are so extensive in proportion to the quantity of the air that is being driven on that the wind slips away into the void beyond.
ἔτι τὸ γίγνεσθαι τὸν ἥλιον ἀχλυώδη καὶ ἀμαυρότερον ἄνευ νέφους, καὶ πρὸ τῶν ὀρθρίων σεισμῶν ἐνίοτε νηνεμίαν τε καὶ κρύος ἰσχυρόν, σημεῖον τῆς εἰρημένης αἰτίας ἐστίν. τόν τε γὰρ ἥλιον ἀχλυώδη καὶ ἀμαυρὸν ἀναγκαῖον εἶναι ὑπονοστεῖν ἀρχομένου τοῦ πνεύματος εἰς τὴν γῆν τοῦ διαλύοντος τὸν ἀέρα καὶ διακρίνοντος, καὶ πρὸς τὴν ἕω καὶ περὶ τοὺς ὄρθρους νηνεμίαν τε καὶ ψῦχος. τὴν μὲν γὰρ νηνεμίαν ἀναγκαῖον ὡς ἐπὶ τὸ πολὺ συμβαίνειν, καθάπερ εἴρηται καὶ πρότερον, οἷον μεταρροίας εἴσω γιγνομένης τοῦ πνεύματος, καὶ μᾶλλον πρὸ τῶν μειζόνων σεισμῶν μὴ διασπώμενον γὰρ τὸ μὲν ἔξω τὸ δ' ἐντός, ἀλλ' ἀθρόως φερόμενον ἀναγκαῖον ἰσχύειν μᾶλλον. τὸ δὲ ψῦχος συμβαίνει διὰ τὸ τὴν ἀναθυμίασιν εἴσω τρέπεσθαι, φύσει θερμὴν οὖσαν καθ' αὑτήν. οὐ δοκοῦσι δ' οἱ ἄνεμοι εἶναι θερμοὶ διὰ τὸ κινεῖν τὸν ἀέρα πλήρη πολλῆς ὄντα καὶ ψυχρᾶς ἀτμίδος, (367b.) ὥσπερ τὸ πνεῦμα <�τὸ> διὰ τοῦ στόματος φυσώμενον καὶ γὰρ τοῦτο ἐγγύθεν μέν ἐστι θερμόν, ὥσπερ καὶ ὅταν ἀάζωμεν, ἀλλὰ δι' ὀλιγότητα οὐχ ὁμοίως ἐπίδηλον, πόρρωθεν δὲ ψυχρὸν διὰ τὴν αὐτὴν αἰτίαν τοῖς ἀνέμοις. ἐκλειπούσης οὖν εἰς τὴν γῆν τῆς τοιαύτης δυνάμεως, συνιοῦσα δι' ὑγρότητα ἡ ἀτμιδώδης ἀπόρροια ποιεῖ τὸ ψῦχος, ἐν οἷς συμβαίνει τόποις γίγνεσθαι τοῦτο τὸ πάθος.	Again, our theory is supported by the facts that the sun appears hazy and is darkened in the absence of clouds, and that there is sometimes calm and sharp frost before earthquakes at sunrise. The sun is necessarily obscured and darkened when the evaporation which dissolves and rarefies the air begins to withdraw into the earth. The calm, too, and the cold towards sunrise and dawn follow from the theory. The calm we have already explained. There must as a rule be calm because the wind flows back into the earth: again, it must be most marked before the more violent earthquakes, for when the wind is not part outside earth, part inside, but moves in a single body, its strength must be greater. The cold comes because the evaporation which is naturally and essentially hot enters the earth. (Wind is not recognized to be hot, because it sets the air in motion, and that is full of a quantity of cold vapour. It is the same with the breath we blow from our mouth: close by it is warm, as it is when we breathe out through the mouth, but there is so little of it that it is scarcely noticed, whereas at a distance it is cold for the same reason as wind.) Well, when this evaporation disappears into the earth the vaporous exhalation concentrates and causes cold in any place in which this disappearance occurs.
τὸ δ' αὐτὸ αἴτιον καὶ τοῦ εἰωθότος ἐνίοτε γίγνεσθαι σημείου πρὸ τῶν σεισμῶν ἢ γὰρ μεθ' ἡμέραν ἢ μικρὸν μετὰ δυσμάς, αἰθρίας οὔσης, νεφέλιον λεπτὸν φαίνεται διατεῖνον καὶ μακρόν, οἷον γραμμῆς μῆκος εὐθύτητι διηκριβωμένον, τοῦ πνεύματος ἀπομαραινομένου διὰ τὴν μετάστασιν. τὸ δ' ὅμοιον συμβαίνει καὶ ἐν τῇ θαλάττῃ περὶ τοὺς αἰγιαλούς ὅταν μὲν γὰρ κυμαίνουσα ἐκβάλλῃ, σφόδρα παχεῖαι καὶ σκολιαὶ γίγνονται αἱ ῥηγμῖνες, ὅταν δὲ γαλήνη ᾖ, διὰ τὸ μικρὰν ποιεῖσθαι τὴν ἔκκρισιν λεπταί εἰσι καὶ εὐθεῖαι. ὅπερ οὖν ἡ θάλαττα ποιεῖ περὶ τὴν γῆν, τοῦτο τὸ πνεῦμα περὶ τὴν ἐν τῷ ἀέρι ἀχλύν, ὥσθ' ὅταν γένηται νηνεμία, πάμπαν εὐθεῖαν καὶ λεπτὴν καταλείπεσθαι ὥσπερ ῥηγμῖνα οὖσαν ἀέρος τὴν νεφέλην. διὰ ταῦτα δὲ καὶ περὶ τὰς ἐκλείψεις ἐνίοτε τῆς σελήνης συμβαίνει γίγνεσθαι σεισμόν ὅταν γὰρ ἤδη πλησίον ᾖ ἡ ἀντίφραξις, καὶ μήπω μὲν ᾖ πάμπαν ἀπολελοιπὸς τὸ φῶς καὶ τὸ ἀπὸ τοῦ ἡλίου θερμὸν ἐκ τοῦ ἀέρος, ἤδη δ' ἀπομαραινόμενον, νηνεμία γίγνεται ἀντιμεθισταμένου τοῦ πνεύματος εἰς τὴν γῆν, ὃ ποιεῖ τὸν σεισμὸν πρὸ τῶν ἐκλείψεων. γίγνονται γὰρ καὶ ἄνεμοι πρὸ τῶν ἐκλείψεων πολλάκις, ἀκρόνυχον μὲν πρὸ τῶν μεσονυκτίων ἐκλείψεων, μεσονύκτιον δὲ πρὸ τῶν ἑῴων. συμβαίνει δὲ τοῦτο διὰ τὸ ἀμαυροῦσθαι τὸ θερμὸν τὸ ἀπὸ τῆς σελήνης, ὅταν πλησίον ἤδη γίγνηται ἡ φορὰ ἐν ᾧ γενομένων ἔσται ἡ ἔκλειψις. ἀνιεμένου οὖν ᾧ κατείχετο ὁ ἀὴρ καὶ ἠρέμει, πάλιν κινεῖται καὶ γίγνεται πνεῦμα τῆς ὀψιαίτερον ἐκλείψεως ὀψιαίτερον.	A sign which sometimes precedes earthquakes can be explained in the same way. Either by day or a little after sunset, in fine weather, a little, light, long-drawn cloud is seen, like a long very straight line. This is because the wind is leaving the air and dying down. Something analogous to this happens on the sea-shore. When the sea breaks in great waves the marks left on the sand are very thick and crooked, but when the sea is calm they are slight and straight (because the secretion is small). As the sea is to the shore so the wind is to the cloudy air; so, when the wind drops, this very straight and thin cloud is left, a sort of wave-mark in the air. An earthquake sometimes coincides with an eclipse of the moon for the same reason. When the earth is on the point of being interposed, but the light and heat of the sun has not quite vanished from the air but is dying away, the wind which causes the earthquake before the eclipse, turns off into the earth, and calm ensues. For there often are winds before eclipses: at nightfall if the eclipse is at midnight, and at midnight if the eclipse is at dawn. They are caused by the lessening of the warmth from the moon when its sphere approaches the point at which the eclipse is going to take place. So the influence which restrained and quieted the air weakens and the air moves again and a wind rises, and does so later, the later the eclipse.

Set quoniam manifestum et cetera. Postquam Philosophus reprobauit opiniones aliorum de terremotu, hic determinat de eo secundum suam opinionem.

Et primo assignat causam terremotus; secundo causam quorundam accidencium circa ipsum, ibi: cum autem fortis factus fuerit et cetera.

Circa primum duo facit: primo assignat causam terremotus; secundo ostendit causam esse bene assignatam, ibi: existit enim terra.

Dicit ergo primo quod dictum est in precedentibus duplicem esse exalationem: unam uaporosam que resoluitur ab humido, alteram fumosam que resoluitur a sicco, et ex hac causatur terremotus.

Secundo ibi: existit enim terra etc., probat causam bene esse assignatam. Et primo per rationem; secundo per signa, ibi: propter quod fiunt et cetera.

Vtitur autem tali ratione: exalatio sicca uentum causat, unde cum infra terram retinetur causat uentum infra terram; uentus autem maxime est motiuus corporum; a uento igitur rationabile est fieri terremotum.

Circa hanc rationem tria facit. Primo manifestat quod exalatio sicca causet uentum infra terram. Et dicit quod licet terra per se sit sicca, tamen propter ymbres quos recipit multam humiditatem habet, ut sic tum ex calore solis, tum ex calore incluso in terra qui est a sole et stellis, causatur multa fumositas exalata ex terra ex qua multum de uento causatur. Et aliquando tota materia uenti a terra eleuatur et causatur uentus in aere; aliquando autem tota materia retinetur intus infra terram et causat infra terram uentum; aliquando autem partim retinetur infra terram et partim eleuatur supra, et sic utrobique uentus causatur.

Secundo ibi: si itaque hoc etc., ostendit quod uentus maxime habet uirtutem ad mouendum corpora. Et dicit quod cum predicte inpossibile sit aliter se habere, oportet considerare quid sit maxime motiuum corporum. Ad quod duo requiruntur, quorum unum est quod possit ad multam distanciam moueri: cum enim corporalia mouencia non moueant nisi moueantur, oportet quod maxime motiuum est ad multum moueri; secundo oportet quod sit uehemens et uiolentum ad hoc quod fortiter impellat. Set quod aliquid sit uehementissimum ad uiolenter impellendum conuenit ex uelocitate motus, quia quod uelociter fertur fortiter percutit; set quod aliquid ad magnam distanciam possit transire conuenit ex subtilitate ratione cuius potest per omnia penetrare. Hec autem duo conueniunt uento, scilicet uelocitas motus et subtilitas, unde sequitur quod uentus maxime possit mouere corpora. Et hoc non solum per rationem, set etiam ad sensum apparet, quia quando igni adhibetur uentus, fit inflammatio et uelociter fertur.

Tercio ibi: non igitur aqua, inducit conclusionem principaliter intentam, scilicet quod causa terremotus non est neque aqua, ut dixit Democritus, neque terra, ut dixit Anaximenes, set uentus, quando scilicet fluxus exalationis infra terram retinetur.

Deinde cum dicit: propter quod fiunt etc., manifestat causam assignatam per signa. Et primo per signa accepta ab ipsis uentis; secundo per signa accepta ab inferioribus rebus, ibi: adhuc autem circa loca; tercio a rebus in alto existentibus, ibi: adhuc solem fieri caliginosum.

Circa primum tria facit. Primo ponit signum a uentis sumptum generaliter. Et dicit quod quia terremotus fit a uento infra terram retento, plurimi et maximi terremotuum fiunt quando aer est tranquillus a uentis, quia cum tota exalatio que resoluitur a terra et est materia uenti sit quasi aliquid unum continuum, ut in pluribus sequitur impetum principii; unde si id quod id quod primo exalat feratur infra terram, tota exalatio infra terram continebitur, et sic omnes uenti erunt infra terram causantes terremotum et extra erit tranquillitas; e conuerso autem erit si principium exalationis feratur extra. Secundo ibi: quosdam autem fieri, excludit quandam obiectionem que posset fieri ex hoc quod aliquando terremotus accidunt etiam uentis in aere existentibus. Et dicit quod hoc non est irrationabile: uidemus enim quod etiam in aere quandoque flant plures uenti simul, sicut ex superioribus patet, unde cum causentur duo uenti quorum unus feratur infra terram faciens terremotum et alius sit in aere, sequetur quod terremotus sit simul cum uento in aere. Set tamen necesse est quod huiusmodi terremotus sint minores, quia exalatio que est causa et principium est diuisa, partim fluens extra et partim retenta intus.

Tercio ibi: nocte autem, prosequitur istud signum quod a uentis assumpsit in quibusdam specialibus. Et dicit quod in nocte fiunt plures et maiores terremotus quam in die, set illi qui fiunt de die sunt maiores qui sunt circa meridiem. Et assignat causam quare diurnorum terremotuum sunt maximi qui sunt circa meridiem, quia scilicet hec hora diei ut in pluribus est maxime tranquilla a uentis, quia quando sol maxime habet uictoriam super terram, facit exalationem causantem uentos declinare infra terram: illud enim quod tunc eleuatur in altum propter uictoriam solis rarefactum consumitur et dispergitur; set quia non habet tantam uictoriam infra terram, resoluit quidem exalationem, set non consumit eam; et inde est quod quando maxime sol obtinet super terram, maxime exalatio includitur infra terram. Vnde cum maxime habeat uictoriam in hora meridiei, tunc maxime exalatio declinat infra terram tranquillitate in aere existente, et ideo diurnorum terremotuum maximi fiunt in meridie. Set in nocte fiunt adhuc magis, quia in nocte fit tranquillitas in aere, quia exalationes causantes uentos non ita eleuantur propter absenciam solis sicut in die, etsi aliquando contingant in nocte uenti propter exalationes prius eleuatas; et ideo facta resolutione exalationum in die apud presenciam solis, quia cessat causa eleuans in nocte, recurrunt exalationes in contrarium, scilicet infra terram, et ideo terremotus causantur in noctibus; et maxime circa diluculum, quia de nocte exalationes infra terram retente quasi congelantur, set circa diluculum propter appropinquationem solis resoluuntur exalationes et excitantur uenti; unde si principium uentorum inueniatur sub terra, faciet fortiorem terremotum propter multitudinem materie recurrentis infra terram, sicut accidit de motu Eurippi, qui propter recursum aque fortiter mouetur.

Deinde cum dicit: adhuc autem circa loca, manifestat predictam causam terremotus per signa a rebus inferioribus accepta. Et primo ponit signa generalia; secundo quedam signa specialia, ibi: signa autem horum.

Circa primum tria facit: primo ponit signa accepta a locis; secundo signa accepta a temporibus, ibi: et uere autem et autumpno; tercio signa accepta a nostris corporibus, ibi: oportet enim intelligere.

Dicit ergo primo quod quia terremotus causantur ex uento infra terram retento, inde est quod circa illa loca fiunt maximi terremotus in quibus uel mare habet magnum fluxum uel terra est spongiosa et cauernosa. Et ponit exemplum de quibusdam locis, sicut est in Ellesponto et in Achaia et in Sicilia, et circa quedam alia loca in quibus uidetur mare penetrare sub terra propter cauernositatem terre. Et ex ista causa, quia scilicet terra est subantrosa et mare fortiter impellit, dicit esse factas in quodam loco thermas, id est emanationes aquarum calidarum: nam propter impulsionem que fit ex motu maris infra terram, excitatur calor et ignitio interius, et maxime si sint loca cauernosa in quibus aer contineatur, et per huiusmodi adustionem redditur terra sulfurea. Dicit autem quod circa loca predicta que sunt uicina mafi fluxili maximi fiunt terremotus propter angustationem interioris uenti ab impulsu maris ipsum exalare non permittentis, quia uentus uehemens qui natus erat exire a terra repellitur iterum in terram propter multitudinem maris que impellitur a uento exteriori uersus terram. Assignat etiam causam quare in locis cauernosis fiunt terremotus. Et dicit quod quecunque regiones habent sub terra loca cauernosa que dicuntur inania, quia non sunt plena corpore solido, magis concutiuntur per terremotus, quia in huiusmodi cauernis recipiunt multum de uento.

Deinde cum dicit: et uere autem et autumpno, ponit signa sumpta ex temporibus. Et dicit quod maxime fiunt terremotus in uere et in autumpno, et fiunt etiam in siccitatibus et in temporibus pluuiosis propter eandem causam, scilicet quia terremotus ex uentis causantur, unde maxime fiunt in uere et in autumpno: in hyeme enim propter frigiditatem et gelu inmobilitantur uenti quia frigiditas impedit resolutionem exalationum que est materia uentorum; in estate uero propter inmensum estum et siccitatem, ita quod non est materia in terra ex qua exalatio resoluatur (sicut ex lignis ualde siccis resoluitur modicus fumus), quia tunc maxime obtinet sol super terram.

Posset autem obici de hoc quod supra dixit quod in meridie maximi fiunt terremotus quia tunc maxime obtinet sol super terram, unde si in estate maxime obtinet, uidetur quod tunc maxime debeant fieri terremotus.

Set non est simile, quia uictoria solis que est in meridie licet sufficiat ad desiccandum superficiales humiditates terre ut non possint exalationes congregari ad exalationem uenti, non tamen sufficit ad totalem desiccationem terre qualis accidit in estate, per quam etiam nec interiores humiditates supersunt ex quibus materia uentorum resolui possit.

Assignat etiam causam quare in temporibus siccis fiunt terremotus, quia tunc aer est uentosus: hoc enim, scilicet aer, est achimos, id est sine humore, quando plus fit de exalatione sicca quam de humida, que quidem exalatio sicca est uentorum materia; set tamen intelligendum est: quando non est tanta siccitas que humiditatem terre consumat ut exalatio impediatur, ut accidit aliquando in estate. Set in temporibus pluuiosis fit terremotus propter multitudinem exalationis que concluditur in locis artis sub terra et constringitur in minorem locum propter hoc quod concauitates terre temporibus pluuiosis replete sunt aqua; et ideo cum exalatio multiplicata inceperit habere uictoriam, uentus ex ea generatus propter constrictionem impingit ad partes terre et fortiter mouet.

Deinde cum dicit: oportet enim intelligere, ponit signa que accipiuntur ex corporibus nostris. Et dicit, quod sicut in corpore nostro tremor et pulsus accidit ex spiritu incluso qui non habet liberum exitum, similiter facit spiritus inclusus in terram; unde aliquis terremotus est sicut tremor et aliquis sicut pulsus. Et dicit quod sicut post urinationem frequenter accidit in corpore tremor eo quod subito uentus ab exteriori intrat interius permeatus unde exit urina, sic accidit et circa terram, nam uentus interius inclusus facit terre tremorem. Quod autem uentus habeat magnam uirtutem ad mouendum apparet non solum ex hiis que facit in aere, ubi potest dici quod magna facit propter suam magnitudinem, set etiam ex hiis que facit in corporibus nostris modicus spiritus in nobis inclusus: manifestum est enim quod spasmi et tetani, qui accidunt ex contractione neruorum, sunt propter motus spiritus qui retrahitur et retractus retrahit neruos; huiusmodi autem spasmi tam uiolentum motum habent ut multi congregati aliquando temptauerunt per uiolenciam retinere ne nerui contraherentur, et tamen non potuerunt uincere motum infirmancium. Et sic oportet intelligere, ut fiat comparatio minoris ad maius, quod uentus inclusus in terra cum magna uiolencia terram mouet.

Deinde cum dicit: signa autem horum, ponit signa ex quibusdam particularibus accidentibus. Quorum primum est quod dicit quendam terremotum in aliquibus locis factum fuisse qui non desiit quousque erumperet uentus qui mouebat terram manifeste extra terram ad modum quo uentus qui uocatur enefias, de quo infra dicetur, exit a nube. Et hoc dicit suo tempore accidisse in Ponto circa Eracleam, et prius dicit hoc accidisse in insula sacra, hoc est Vulcani, in qua intumuit quandoque terra et eleuata est cum sono quedam moles ad modum collis, que tandem propter uiolenciam uenti interioris rupta fuit, et exiuit inde multus uentus eleuans fauillam et cinerem, propter quod repleta fuit ciuitas Lipareorum cinere, et cinis ille peruenit ad multas ciuitates Ytalie. Et dicit apparuisse illius facti uestigia usque ad tempus suum: causa enim est illius ignis qui in illa insula apparet, uel in aliqua alia terra, quod aer infra terram in paruas partes diuiditur, et ex motu ignitur, et ex tali ignitione primo terra accenditur, et istius accensionis diu durat effectus.

Secundum autem signum particulare ponit ibi: Argumentum autem est. Et dicit quod possumus accipere argumentum quod uenti fluant sub terra illud quod accidit circa has insulas, scilicet Vulcanum et alias insulas dictas Eoli, quia huiusmodi insule presignificant quando debeat auster flare quodam sono qui causatur ex hoc quod quando modicum incipit auster flare a remotis et a mari, illud quod debebat extra terram exsufflare de uento iterum repellitur intus propter mare quod superuenit, et sic fit sonus, tamen quandoque sine seismo, id est terremotu, tum propter hoc quod loca cauernosa infra terram sunt ampla ita quod uentus interius conclusus dispergitur in inmensum, tum etiam propter paucitatem que est exalationis repulse, que quandoque pauca est et non sufficit facere terremotum.

Deinde cum dicit: adhuc solem fieri caliginosum, ponit signa accepta a rebus que fiunt in alto. Et diuiditur in tres partes secundum tria signa que ponit: secunda pars incipit ibi: idem autem causa; tercia ibi: propter eandem autem.

Dicit ergo primo quod oportet pro signo accipere cause assignate de terremotu hoc quod circa terremotum fit sol caliginosus et obscurus sine nube manifesta, et quod ante terremotus qui fiunt de mane aliquando accidit tranquillitas in aere et magnum frigus. Ideo enim sol circa terremotum apparet caliginosus et obscurus, quia uentus qui poterat rarefacere aerem et disgregare exalationes incipit subintrare terram circa tempus terremotus. Similiter etiam ante matutinos terremotus fit tranquillitas, quia sicut dictum est, ut plurimum accidit tranquillitas ante terremotus uento incluso infra terram, et maxime hoc accidit circa magnos terremotus, quia quando principium uenti non diuiditur ut una pars eius procedat infra terram et alia extra terram, set totum simul feratur, tunc necesse est quod magis ualeat uentus ad mouendum uel aerem uel terram. Ideo autem accidit frigus ante terremotus, quia exalatio que secundum naturam suam calida est, utpote adhuc aliquid retinens de uirtute caloris resoluentis ipsam, non est in aere, set conuertitur infra terram. Licet autem exalatio secundum se sit calida, tamen uenti non uidentur esse calidi, quia commouent aerem plenum multo uapore frigido cuius uaporis frigiditas magis sentitur per huiusmodi commotionem, sicut etiam spiritus per os exsufflatus secundum se calidus est et sic sentitur de prope, sicut cum hyamus, set de longe frigidus sentitur propter eandem causam, scilicet propter uaporem frigidum quem commouet, licet non sit similiter manifestum de flatu nostro sicut de uento propter paucitatem. Quando igitur talis exalatio concluditur infra terram terremotu instante, rationabile est quod circa illa loca in quibus accidit terremotus uapores humidi resoluti in aere existentes faciant frigus.

Deinde cum dicit: idem autem causa etc., ponit aliud signum. Et dicit quod hoc quidem, scilicet uentum concludi infra terram et cessare in aere, est causa eius quod consueuit accipi ut signum precedens terremotum, quia ante terremotum de nocte, per diem uel post solis occasum, si sit serenitas, apparet quedam nubecula subtilis in longum porrecta et directa, per quod significatur quod uentus defecerit in aere et sit inclusus infra terram. Sicut enim circa litora maris, quando fuerit magnus uentus fluctuare faciens mare, fiunt grosse et distorte regmines, id est undositates, cum autem mare fuerit placatum, fiunt subtiles et recte propter paruam commotionem maris a uento; sic accidit in aere circa caliginem quod quando est tranquillitas in aere, derelinquitur recta et subtilis, tanquam talis nubecula sic se habeat ad aerem sicut regmis ad mare.

Deinde cum dicit: propter eandem autem, ponit tercium signum. Et dicit quod propter eandem causam, scilicet tranquillitatem existentem in aere, aliquando fit terremotus circa eclipsim lune, id est quam luna facit per sui interpositionem inter nos et solem, quod fit in eclipsi solis, quia quando iam prope est tempus quod luna interponatur inter nos et solem, et lumen et caliditas solis nondum est deficiens ex aere, set iam est marcefactum, id est debilitatum, tunc fit tranquillitas in aere, quia cum calor debilis non possit eleuare exalationes in altum, feruntur infra terram, et tunc spiritus intra terram retentus facit terremotum ante eclipses. Set et aliquando fiunt uenti ante eclipses lunares, in principio quidem noctis ante eclipses que fiunt in media nocte, in media autem nocte ante eclipses que fiunt diluculo. Et hoc accidit propter hoc quod calor qui est in aere a luna debilitatur cum luna appropinquat loco eclipsis; uirtute autem caloris lunaris detinetur aer ne perturbetur et quiescit: luna enim habet manifestum effectum in conseruatione rerum inferiorum et precipue humidarum; et ideo diminuto calore lune turbatur aer et fit uentus. Et si eclipsis fit tardior, id est maiorem moram habens, uentus etiam est durabilior.

Vel potest aliter exponi ut hoc etiam quod supra dictum est, quod circa eclipses lune accidit fieri terremotum, intelligatur de eclipsibus lunaribus; et quod dicit quod cum iam prope fuerit interpositio, non intelligatur de interpositione lune inter nos et solem, set de interpositione umbre terre; et quod dicit lumen el calidum quod est a sole nondum deficere ex aere, intelligendum est de lumine et calido quod luna recipit a sole.

Set tunc uidetur duo contraria dicere: primo quidem enim dixit quod ante eclipses lunares fit tranquillitas deficiente calido, postea uero dixit quod ante eclipses lunares diminuto eius calido fit turbatio aeris.

Potest autem ad hoc dici quod diminutio calidi quod est a luna quandoque facit tranquillitatem, quando scilicet calor lune erat moderatus et contemperatus ad mouendum exalationes ad generationem uentorum, unde diminutio caloris facit uentos cessare; quando autem caliditas lune erat maior, quasi uincens exalationes et disgregans eas, tunc calor lune facit tranquillitatem et diminutio eius caloris facit uentos.

Potest etiam dici quod parum ante eclipses lunares fit tranquillitas propter magnam diminutionem lunaris caliditatis; dicit autem philosophus uentos fieri non inmediate ante eclipses, set per mediam noctem ante, quia tunc aliquantulum remissus est calor lune, et non totaliter marcefactus, id est debilitatus.

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Lectio 15

ὅταν δ' ἰσχυρὸς γένηται σεισμός, οὐκ εὐθὺς οὐδ' εἰσάπαξ παύεται σείσας, ἀλλὰ τὸ πρῶτον μὲν μέχρι περὶ τετταράκοντα πρόεισι πολλάκις ἡμέρας, ὕστερον δὲ καὶ ἐφ' (368a.) ἓν καὶ ἐπὶ δύο ἔτη ἐπισημαίνει κατὰ τοὺς αὐτοὺς τόπους. αἴτιον δὲ τοῦ μὲν μεγέθους τὸ πλῆθος τοῦ πνεύματος καὶ τῶν τόπων τὰ σχήματα δι' οἵων ἂν ῥυῇ ᾗ γὰρ ἂν ἀντιτυπήσῃ καὶ μὴ ῥᾳδίως διέλθῃ, μάλιστά τε σείει καὶ ἐγκαταλείπεσθαι ἀναγκαῖον ἐν ταῖς δυσχωρίαις, οἷον ὕδωρ ἐν σκεύει οὐ δυνάμενον διεξελθεῖν. διὸ καθάπερ ἐν σώματι οἱ σφυγμοὶ οὐκ ἐξαίφνης παύονται οὐδὲ ταχέως, ἀλλ' ἐκ προσαγωγῆς ἅμα καταμαραινομένου τοῦ πάθους, καὶ ἡ ἀρχὴ ἀφ' ἧς ἡ ἀναθυμίασις ἐγένετο καὶ ἡ ὁρμὴ τοῦ πνεύματος δῆλον ὅτι οὐκ εὐθὺς ἅπασαν ἀνήλωσεν τὴν ὕλην, ἐξ ἧς ἐποίησε τὸν ἄνεμον, ὃν καλοῦμεν σεισμόν. ἕως ἂν οὖν ἀναλωθῇ τὰ ὑπόλοιπα τούτων, ἀνάγκη σείειν, ἠρεμαιότερον δὲ καὶ μέχρι τούτου ἕως ἂν ἔλαττον ᾖ τὸ ἀναθυμιώμενον ἢ ὥστε δύνασθαι κινεῖν ἐπιδήλως. ποιεῖ δὲ καὶ τοὺς ψόφους τοὺς ὑπὸ τὴν γῆν γιγνομένους τὸ πνεῦμα, καὶ τοὺς πρὸ τῶν σεισμῶν καὶ ἄνευ δὲ σεισμῶν ἤδη που γεγόνασιν ὑπὸ γῆν ὥσπερ γὰρ καὶ ῥαπιζόμενος ὁ ἀὴρ παντοδαποὺς ἀφίησι ψόφους, οὕτως καὶ τύπτων αὐτός οὐδὲν γὰρ διαφέρει τὸ γὰρ τύπτον ἅμα καὶ αὐτὸ τύπτεται πᾶν. προέρχεται δὲ ὁ ψόφος τῆς κινήσεως διὰ τὸ λεπτομερέστερον εἶναι καὶ μᾶλλον διὰ παντὸς ἰέναι τοῦ πνεύματος τὸν ψόφον. ὅταν δ' ἔλαττον ᾖ ἢ ὥστε κινῆσαι τὴν γῆν διὰ λεπτότητα, διὰ μὲν τὸ ῥᾳδίως διηθεῖσθαι οὐ δύναται κινεῖν, διὰ δὲ τὸ προσπίπτειν στερεοῖς ὄγκοις καὶ κοίλοις καὶ παντοδαποῖς σχήμασι παντοδαπὴν ἀφίησι φωνήν, ὥστ' ἐνίοτε δοκεῖν ὅπερ λέγουσιν οἱ τερατολογοῦντες, μυκᾶσθαι τὴν γῆν.	A severe earthquake does not stop at once or after a single shock, but first the shocks go on, often for about forty days; after that, for one or even two years it gives premonitory indications in the same place. The severity of the earthquake is determined by the quantity of wind and the shape of the passages through which it flows. Where it is beaten back and cannot easily find its way out the shocks are most violent, and there it must remain in a cramped space like water that cannot escape. Any throbbing in the body does not cease suddenly or quickly, but by degrees according as the affection passes off. So here the agency which created the evaporation and gave it an impulse to motion clearly does not at once exhaust the whole of the material from which it forms the wind which we call an earthquake. So until the rest of this is exhausted the shocks must continue, though more gently, and they must go on until there is too little of the evaporation left to have any perceptible effect on the earth at all. Subterranean noises, too, are due to the wind; sometimes they portend earthquakes but sometimes they have been heard without any earthquake following. Just as the air gives off various sounds when it is struck, so it does when it strikes other things; for striking involves being struck and so the two cases are the same. The sound precedes the shock because sound is thinner and passes through things more readily than wind. But when the wind is too weak by reason of thinness to cause an earthquake the absence of a shock is due to its filtering through readily, though by striking hard and hollow masses of different shapes it makes various noises, so that the earth sometimes seems to 'bellow' as the portentmongers say.
ἤδη δὲ καὶ ὕδατα ἀνερράγη γιγνομένων σεισμῶν ἀλλ' οὐ διὰ τοῦτο αἴτιον τὸ ὕδωρ τῆς κινήσεως, ἀλλ' ἂν ᾖ ἐξ ἐπιπολῆς ἢ κάτωθεν βιάζηται τὸ πνεῦμα, ἐκεῖνο τὸ κινοῦν ἐστιν, ὥσπερ τῶν κυμάτων οἱ ἄνεμοι ἀλλ' οὐ τὰ κύματα τῶν ἀνέμων εἰσὶν αἴτια, ἐπεὶ καὶ τὴν γῆν οὕτως ἄν τις αἰτιῷτο τοῦ πάθους ἀνατρέπεται γὰρ σειομένη, καθάπερ ὕδωρ (ἡ γὰρ ἔκχυσις ἀνάτρεψίς τίς ἐστιν). ἀλλ' αἴτια ταῦτα μὲν ἄμφω ὡς ὕλη (πάσχει γάρ, ἀλλ' οὐ ποιεῖ), τὸ δὲ πνεῦμα ὡς ἀρχή. ὅπου δ' ἅμα κῦμα σεισμῷ γέγονεν, αἴτιον, ὅταν ἐναντία γίγνηται τὰ πνεύματα. τοῦτο δὲ γίγνεται ὅταν τὸ (368b.) σεῖον τὴν γῆν πνεῦμα φερομένην ὑπ' ἄλλου πνεύματος τὴν θάλατταν ἀπῶσαι μὲν ὅλως μὴ δύνηται, προωθοῦν δὲ καὶ συστέλλον εἰς ταὐτὸν συναθροίσῃ πολλήν τότε γὰρ ἀναγκαῖον ἡττηθέντος τούτου τοῦ πνεύματος ἀθρόαν ὠθουμένην ὑπὸ τοῦ ἐναντίου πνεύματος ἐκρήγνυσθαι καὶ ποιεῖν τὸν κατακλυσμόν. ἐγένετο δὲ τοῦτο καὶ περὶ Ἀχαΐαν ἔξω μὲν γὰρ ἦν νότος, ἐκεῖ δὲ βορέας, νηνεμίας δὲ γενομένης καὶ ῥυέντος εἴσω τοῦ ἀνέμου ἐγένετο τό τε κῦμα καὶ ὁ σεισμὸς ἅμα, καὶ μᾶλλον διὰ τὸ τὴν θάλατταν μὴ διδόναι διαπνοὴν τῷ ὑπὸ τὴν γῆν ὡρμημένῳ πνεύματι, ἀλλ' ἀντιφράττειν ἀποβιαζόμενα γὰρ ἄλληλα τὸ μὲν πνεῦμα τὸν σεισμὸν ἐποίησεν, ἡ δ' ὑπόστασις τοῦ κύματος τὸν κατακλυσμόν.	Water has been known to burst out during an earthquake. But that does not make water the cause of the earthquake. The wind is the efficient cause whether it drives the water along the surface or up from below: just as winds are the causes of waves and not waves of winds. Else we might as well say that earth was the cause; for it is upset in an earthquake, just like water (for effusion is a form of upsetting). No, earth and water are material causes (being patients, not agents): the true cause is the wind. The combination of a tidal wave with an earthquake is due to the presence of contrary winds. It occurs when the wind which is shaking the earth does not entirely succeed in driving off the sea which another wind is bringing on, but pushes it back and heaps it up in a great mass in one place. Given this situation it follows that when this wind gives way the whole body of the sea, driven on by the other wind, will burst out and overwhelm the land. This is what happened in Achaea. There a south wind was blowing, but outside a north wind; then there was a calm and the wind entered the earth, and then the tidal wave came on and simultaneously there was an earthquake. This was the more violent as the sea allowed no exit to the wind that had entered the earth, but shut it in. So in their struggle with one another the wind caused the earthquake, and the wave by its settling down the inundation.
κατὰ μέρος δὲ γίγνονται οἱ σεισμοὶ τῆς γῆς, καὶ πολλάκις ἐπὶ μικρὸν τόπον, οἱ δ' ἄνεμοι οὔ κατὰ μέρος μέν, ὅταν αἱ ἀναθυμιάσεις αἱ κατὰ τὸν τόπον αὐτὸν καὶ τὸν γειτνιῶντα συνέλθωσιν εἰς ἕν, ὥσπερ καὶ τοὺς αὐχμοὺς ἔφαμεν γίγνεσθαι καὶ τὰς ὑπερομβρίας τὰς κατὰ μέρος. καὶ οἱ μὲν σεισμοὶ γίγνονται διὰ τοῦτον τὸν τρόπον, οἱ δ' ἄνεμοι οὔ τὰ μὲν γὰρ ἐν τῇ γῇ τὴν ἀρχὴν ἔχει, ὥστ' ἐφ' ἓν ἁπάσας ὁρμᾶν ὁ δ' ἥλιος οὐχ ὁμοίως δύναται, τὰς δὲ μετεώρους μᾶλλον, ὥστε ῥεῖν, ὅταν ἀρχὴν λάβωσιν ἀπὸ τῆς τοῦ ἡλίου φορᾶς ἤδη κατὰ τὰς διαφορὰς τῶν τόπων, ἐφ' ἕν. ὅταν μὲν οὖν ᾖ πολὺ τὸ πνεῦμα, κινεῖ τὴν γῆν, ὥσπερ δὲ ὁ τρόμος, ἐπὶ πλάτος γίγνεται δ' ὀλιγάκις καὶ κατά τινας τόπους, οἷον σφυγμός, ἄνω κάτωθεν διὸ καὶ ἐλαττονάκις σείει τοῦτον τὸν τρόπον οὐ γὰρ [δίδωσιν] ῥᾴδιον οὕτω πολλὴν συνελθεῖν ἀρχήν ἐπὶ μῆκος γὰρ πολλαπλασία τῆς ἀπὸ τοῦ βάθους ἡ διάκρισις. ὅπου δ' ἂν γένηται τοιοῦτος σεισμός, ἐπιπολάζει πλῆθος λίθων, ὥσπερ τῶν ἐν τοῖς λίκνοις ἀναβραττομένων τοῦτον γὰρ τὸν τρόπον γενομένου σεισμοῦ τά τε περὶ Σίπυλον ἀνετράπη καὶ τὸ Φλεγραῖον καλούμενον πεδίον καὶ τὰ περὶ τὴν Λιγυστικὴν χώραν. ἐν δὲ ταῖς νήσοις ταῖς ποντίαις ἧττον γίγνονται σεισμοὶ τῶν προσγείων τὸ γὰρ πλῆθος τῆς θαλάττης καταψύχει τὰς ἀναθυμιάσεις καὶ κωλύει τῷ βάρει καὶ ἀποβιάζεται ἔτι δὲ ῥεῖ καὶ οὐ σείεται (369a.) κρατουμένη ὑπὸ τῶν πνευμάτων καὶ διὰ τὸ πολὺν ἐπέχειν τόπον οὐκ εἰς ταύτην ἀλλ' ἐκ ταύτης αἱ ἀναθυμιάσεις γίγνονται, καὶ ταύταις ἀκολουθοῦσιν αἱ ἐκ τῆς γῆς. αἱ δ' ἐγγὺς τῆς ἠπείρου μόριόν εἰσιν τῆς ἠπείρου τὸ γὰρ μεταξὺ διὰ μικρότητα οὐδεμίαν ἔχει δύναμιν τὰς δὲ ποντίας οὐκ ἔστιν κινῆσαι ἄνευ τῆς θαλάττης ὅλης, ὑφ' ἧς περιεχόμεναι τυγχάνουσιν. περὶ μὲν οὖν σεισμῶν, καὶ τίς ἡ φύσις, καὶ διὰ τίνα αἰτίαν γίγνονται, καὶ περὶ τῶν ἄλλων τῶν συμβαινόντων περὶ αὐτούς, εἴρηται σχεδὸν περὶ τῶν μεγίστων.	Earthquakes are local and often affect a small district only; whereas winds are not local. Such phenomena are local when the evaporations at a given place are joined by those from the next and unite; this, as we explained, is what happens when there is drought or excessive rain locally. Now earthquakes do come about in this way but winds do not. For earthquakes, rains, and droughts have their source and origin inside the earth, so that the sun is not equally able to direct all the evaporations in one direction. But on the evaporations in the air the sun has more influence so that, when once they have been given an impulse by its motion, which is determined by its various positions, they flow in one direction. When the wind is present in sufficient quantity there is an earthquake. The shocks are horizontal like a tremor; except occasionally, in a few places, where they act vertically, upwards from below, like a throbbing. It is the vertical direction which makes this kind of earthquake so rare. The motive force does not easily accumulate in great quantity in the position required, since the surface of the earth secretes far more of the evaporation than its depths. Wherever an earthquake of this kind does occur a quantity of stones comes to the surface of the earth (as when you throw up things in a winnowing fan), as we see from Sipylus and the Phlegraean plain and the district in Liguria, which were devastated by this kind of earthquake. Islands in the middle of the sea are less exposed to earthquakes than those near land. First, the volume of the sea cools the evaporations and overpowers them by its weight and so crushes them. Then, currents and not shocks are produced in the sea by the action of the winds. Again, it is so extensive that evaporations do not collect in it but issue from it, and these draw the evaporations from the earth after them. Islands near the continent really form part of it: the intervening sea is not enough to make any difference; but those in the open sea can only be shaken if the whole of the sea that surrounds them is shaken too. We have now explained earthquakes, their nature and cause, and the most important of the circumstances attendant on their appearance.

Cum autem fortis factus fuerit et cetera. Postquam philosophus assignauit causam terremotus, hic assignat causam accidencium circa ipsos. Et circa hoc duo facit: primo assignat causam generalium accidencium; secundo causam quorundam particularium, ibi: in insulis autem ponticis.

Circa primum tria facit: primo assignat causam durationis terremotuum; secundo causam quorundam effectuum, eius, ibi: facit autem et sonos; tercio assignat causam diuersimode habitudinis ipsius ad terram, ibi: secundum autem partem.

Dicit ergo primo quod quando fuerit fortis terremotus, non statim cessat, neque ad primam agitationem, set aliquando quod est primum in eius duratione agitat usque ad quadraginta dies interpolatis noctibus, et post hoc usque ad unum uel duos annos. Cuius causa ex duobus sumitur, scilicet ex multitudine uenti et ex figura locorum per que fluit uentus. Quando enim loca subterranea sunt arta et solida ut spiritus repulsus non facile pertranseat, tunc maxime concutit et intus maxime retinetur, sicut aqua non potens transire. Et ideo sicut quando ab aliqua passione, puta ire, incitatur pulsus in corpore humano, non repente cessat, neque in paruo tempore, set post magnam horam debilitata passione, sic accidit in uento mouente terram. Sic igitur accidit duratio terremotus propter figuram loci. Accidit etiam propter multitudinem materie, quia illud principium ex quo facta fuit exalatio ex qua natus est uentus concutiens terram non statim totam materiam exalationis expendit per resolutionem; quousque ergo illa materia consumatur, reliquie illius materie faciunt agitationem, set semper debilius, quousque ueniat ad hoc quod sit ita modica exalatio quod non possit mouere terram.

Deinde cum dicit: facit autem et sonos, assignat causam quorundam effectuum terremotus. Et primo sonorum qui causantur in terra; secundo aquarum que erumpunt a terra propter terremotum, ibi: iam autem et aque; tercio fluctuum qui fiunt in mari, ibi: ubi autem simul.

Dicit ergo primo quod uentus inclusus sub terra qui causat terremotum aliquando facit sonos ante terremotum, et aliquando etiam fiunt soni sine terremotu. Sicut enim aer percussus, utpote uirga uel corrigia discussa in aere, facit sonos, ita etiam quando ipse percutit ad aliquod corporum: non enim est differencia quantum ad hoc utrum ipse uerberet uel uerberetur, quia omne quod uerberat uerberatur propter resistenciam uerberati. Huiusmodi autem sonus a spiritu infra terram incluso causatus precedit terremotum, licet simul fiat cum ipso, quia est subtiliorum parcium, et quia sonus magis potest penetrare per totum quam spiritus, id est uentus. Quod non est sic intelligendum quasi sonus sit corpus partes et subtilitatem habens, set quia in subtiliori aere potest fieri sonus quam uentus. Et ideo etiam fiunt aliquando huiusmodi soni sine terremotu, quia aliquando uentus est minor causans sonum quam sufficiat ad mouendum terram, et propter subtilitatem de facili potest penetrare ut perueniat ad auditum nostrum, licet non possit mouere. Ideo autem causantur diuerse maneries sonorum, quia spiritus inclusus impingit ad moles solidas et concauas et diuersis figuris figuratas, ex qua diuersitate causatur diuersus modus sonorum, ita quod aliquando uideatur terra mugire, secundum quod dicunt illi qui antiquitus uulgabant prodigia, ut aliquibus sacrificiis expiarentur: consuetum enim erat apud antiquos ut quando inconsueta acciderent in aliqua regione, principibus regionis nunciarentur ut a diuinis perquirerent quid pretenderent.

Deinde cum dicit: iam autem et aque eruperunt, assignat rationem de alio effectu terremotus. Et dicit quod aliquando factis terremotibus eruperunt aque de terra. Non tamen propter hoc credendum est quod aqua sit causa terremotus, sicut Democritus dixit, set uentus inclusus in terra qui cum quadam uiolencia mouet aquam, si sit in superficie terre, uel etiam sub terra et subuertendo terram, facit eam apparere, sicut et fluctuatio accidit in mari propter uentos, non tamen fluctus sunt causa uentorum: hac enim ratione posset aliquis etiam terram dicere causam terremotus, quia terra agitata euertitur propter terremotum, sicut aqua effunditur: effusio enim aque est quedam euersio ipsius. Set tamen hec duo, scilicet terra et aqua, in hoc se habent ut materia, quia paciuntur et non agunt.

Deinde cum dicit: ubi autem simul, assignat causam alterius effectus. Et dicit quod quando simul cum terremotu fiunt fluctus in mari, causa est contrarietas uentorum: hoc enim fit quando uentus inclusus in terra qui agitat terram non potest repellere totaliter mare quod contrafertur a contrario uento, set tamen impellendo et coartando congregatur multum de aqua maris circa eundem locum. Cum ergo interior uentus uincatur ab exteriori, tunc necesse est quod mare erumpat super terram et faciat quasi diluuium. Et hoc dicit fuisse factum circa Achaiam, quia in mari fiabat auster, infra terram autem erat quasi uentus borealis, set quando fuit facta tranquillitas, scilicet contraria impugnatione uentorum et uento boreali recurrente infra terram quasi repulso, accidit simul et fluctuatio et terremotus, et maxime propter hoc quod mare obsistebat et non dabat locum perflandi uento subterraneo qui impetum faciebat; et sic dum contra se inuicem uim inferent mare et subterraneus uentus, uentus quidem subterraneus fecit terremotum, set ypostasis spiritus, id est mare quod subsistebat interiorem uentum, obtinendo fecit cataclismum.

Deinde cum dicit: secundum partem autem, assignat rationem quorundam accidencium terremotus ex habitudine ipsius ad terram. Et primo quantum ad hoc quod terremotus accidunt secundum partem; secundum quantum ad diuersos motus quibus terra mouetur, ibi: quando quidem igitur.

Dicit ergo primo quod terremotus non fiunt ita quod tota terra commoueatur, set secundum aliquam partem, et frequenter usque ad modicum locum, set non est ita de uentis. Ideo autem terremotus accidit secundum partes, quia exalationes que fiunt in illo loco et in uicinis locis conueniunt in unum, sicut et supra diximus quod siccitates aliquando accidunt in aliqua parte, uel etiam pluuie, propter congregationem exalationum humidarum in unum locum, et eadem ratione terremotus fiunt in aliqua modica parte terre. Set de uentis qui flant in aere non est sic, quia magis exalationes causantes eos disperguntur; uenti enim qui causant terremotus habent sub terra principium, ita quod omnes faciunt impetum ad unum locum; sol enim non tantum potest infra terram quantum potest supra terram, ut scilicet possit impedire dissoluendo congregationem exalationum sub terra sicut impedit supra terram; set super exalationes suspensas, id est eleuatas, in aere magis potest sol, ita ut cum acceperint principium a motu solis resoluente et eleuante eas, tunc fluant ad aliquod unum secundum differenciam locorum; et sic quandoque fit boreas, quandoque auster, quandoque autem aliquis alius uentus. Fluxus autem subterranei uenti, cum confluit ad unum ut post congregationem possit facere terremotum, non est nobis manifestus sicut fluxus uenti in aere ad unum tendentis; unde uenti apparent diffusi et ad longum spatium flantes, terremotus autem ad modicum.

Deinde cum dicit: Quando quidem igitur, assignat causam de diuerso modo agitationis terre. Et dicit quod quando fuerit multus spiritus congregatus, tunc mouet terram, et si sit motus in latum, fit quasi tremor; aliquando autem fit, set raro, in aliquibus locis motus terre per modum pulsus, quasi aliquid desubtus impellat terram sursum. Set hoc minus fit, quia non est facile quod tantum de exalatione conueniat in unum locum ut possit sic terram sursum impellere: multo enim est maior exalatio que colligitur secundum longitudinem et latitudinem terre quam que potest colligi a profundo. Set ubicunque factus fuerit terremotus per modum pulsus, egreditur ibi multitudo lapidum bulliencium sicut bulliencium in caldariis, eo quod propter uehemenciam motus causatur interius aliqua ignitio; et hoc modo dicit accidisse in subuersione quarundam terrarum.

Deinde cum dicit: in insulis autem ponticis, assignat causam quorundam particularium accidencium. Et dicit quod in insulis ponticis, id est que sunt in profundo maris, minus fiunt terremotus quam in insulis que sunt prope terram, quia multitudo maris infrigidat exalationes ut non resoluantur ad generationem uentorum; et iterum mare suo pondere prohibet et uim infert terre subsidenti ne possit moueri; iterum mare fluit propter uentos hac et illac, et sic non agitatur terra ei subposita a uentis; et quia etiam mare multum locum occupat secundum altitudinem et profunditatem, exalationes maris non concluduntur in terra, set eleuantur sursum, exalationes autem terre subsidentis mare consequuntur etiam exalationes maris in tendendo sursum, et ita non inclusis exalationibus sub terra non fiunt ibi terremotus. Set insule que sunt prope terram sunt quasi partes terre, unde eadem ratio est et de illis et de terra, ut in eis possit accidere terremotus: mare enim quod est intermedium propter suam paruitatem nullam habet uirtutem ad impediendum terremotum. Set insulas que sunt infra mare multum non contingit moueri nisi totum mare moueretur quod eas circumstat, et hoc est difficile propter causas predictas.

The end of Thomas' Commentary

There follows an anonymous commentator.

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Lectio 16

9	9
περὶ δὲ ἀστραπῆς καὶ βροντῆς, ἔτι δὲ περὶ τυφῶνος καὶ πρηστῆρος καὶ κεραυνῶν λέγωμεν καὶ γὰρ τούτων τὴν αὐτὴν ἀρχὴν ὑπολαβεῖν δεῖ πάντων. τῆς γὰρ ἀναθυμιάσεως, ὥσπερ εἴπομεν, οὔσης διττῆς, τῆς μὲν ὑγρᾶς τῆς δὲ ξηρᾶς, καὶ τῆς συγκρίσεως ἐχούσης ἄμφω ταῦτα δυνάμει καὶ συνισταμένης εἰς νέφος, ὥσπερ εἴρηται πρότερον, ἔτι δὲ πυκνοτέρας τῆς συστάσεως τῶν νεφῶν γιγνομένης πρὸς τὸ ἔσχατον πέρας (ᾗ γὰρ ἐκλείπει τὸ θερμὸν διακρινόμενον εἰς τὸν ἄνω τόπον, ταύτῃ πυκνοτέραν καὶ ψυχροτέραν ἀναγκαῖον εἶναι τὴν σύστασιν διὸ καὶ οἱ κεραυνοὶ καὶ οἱ ἐκνεφίαι καὶ πάντα τὰ τοιαῦτα φέρεται κάτω, καίτοι πεφυκότος ἄνω τοῦ θερμοῦ φέρεσθαι παντός ἀλλ' εἰς τοὐναντίον τῆς πυκνότητος ἀναγκαῖον γίγνεσθαι τὴν ἔκθλιψιν, οἷον οἱ πυρῆνες οἱ ἐκ τῶν δακτύλων ἐκπηδῶντες καὶ γὰρ ταῦτα βάρος ἔχοντα φέρεται πολλάκις ἄνω) ἡ μὲν οὖν ἐκκρινομένη θερμότης εἰς τὸν ἄνω διασπείρεται τόπον ὅση δ' ἐμπεριλαμβάνεται τῆς ξηρᾶς ἀναθυμιάσεως ἐν τῇ μεταβολῇ ψυχομένου τοῦ ἀέρος, αὕτη συνιόντων τῶν νεφῶν ἐκκρίνεται, βίᾳ δὲ φερομένη καὶ προσπίπτουσα τοῖς περιεχομένοις νέφεσι ποιεῖ πληγήν, ἧς ὁ ψόφος καλεῖται βροντή. γίγνεται δ' ἡ πληγὴ τὸν αὐτὸν τρόπον, ὡς παρεικάσαι μείζονι μικρὸν πάθος, τῷ ἐν τῇ φλογὶ γιγνομένῳ ψόφῳ, ὃν καλοῦσιν οἱ μὲν τὸν Ἥφαιστον γελᾶν, οἱ δὲ τὴν Ἑστίαν, οἱ δ' ἀπειλὴν τούτων. γίγνεται δ' ὅταν ἡ ἀναθυμίασις εἰς τὴν φλόγα συνεστραμμένη φέρηται, ῥηγνυμένων καὶ ξηραινομένων τῶν ξύλων οὕτως γὰρ καὶ ἐν τοῖς νέφεσι ἡ γιγνομένη τοῦ πνεύματος ἔκκρισις πρὸς τὴν πυκνότητα τῶν νεφῶν ἐμπίπτουσα (369b.) ποιεῖ τὴν βροντήν.	Let us go on to explain lightning and thunder, and further whirlwind, fire-wind, and thunderbolts: for the cause of them all is the same. As we have said, there are two kinds of exhalation, moist and dry, and the atmosphere contains them both potentially. It, as we have said before, condenses into cloud, and the density of the clouds is highest at their upper limit. (For they must be denser and colder on the side where the heat escapes to the upper region and leaves them. This explains why hurricanes and thunderbolts and all analogous phenomena move downwards in spite of the fact that everything hot has a natural tendency upwards. Just as the pips that we squeeze between our fingers are heavy but often jump upwards: so these things are necessarily squeezed out away from the densest part of the cloud.) Now the heat that escapes disperses to the up region. But if any of the dry exhalation is caught in the process as the air cools, it is squeezed out as the clouds contract, and collides in its rapid course with the neighbouring clouds, and the sound of this collision is what we call thunder. This collision is analogous, to compare small with great, to the sound we hear in a flame which men call the laughter or the threat of Hephaestus or of Hestia. This occurs when the wood dries and cracks and the exhalation rushes on the flame in a body. So in the clouds, the exhalation is projected and its impact on dense clouds causes thunder: the variety of the sound is due to the irregularity of the clouds and the hollows that intervene where their density is interrupted. This then, is thunder, and this its cause.
παντοδαποὶ δὲ ψόφοι διὰ τὴν ἀνωμαλίαν τε γίγνονται τῶν νεφῶν καὶ διὰ τὰς μεταξὺ κοιλίας, ᾗ τὸ συνεχὲς ἐκλείπει τῆς πυκνότητος. ἡ μὲν οὖν βροντὴ τοῦτ' ἔστι, καὶ γίγνεται διὰ ταύτην τὴν αἰτίαν τὸ δὲ πνεῦμα τὸ ἐκθλιβόμενον τὰ πολλὰ μὲν ἐκπυροῦται λεπτῇ καὶ ἀσθενεῖ πυρώσει, καὶ τοῦτ' ἔστιν ἣν καλοῦμεν ἀστραπήν, ᾗ ἂν ὥσπερ ἐκπῖπτον τὸ πνεῦμα χρωματισθὲν ὀφθῇ. γίγνεται δὲ μετὰ τὴν πληγὴν καὶ ὕστερον τῆς βροντῆς ἀλλὰ φαίνεται πρότερον διὰ τὸ τὴν ὄψιν προτερεῖν τῆς ἀκοῆς. δηλοῖ δ' ἐπὶ τῆς εἰρεσίας τῶν τριήρων ἤδη γὰρ ἀναφερόντων πάλιν τὰς κώπας ὁ πρῶτος ἀφικνεῖται ψόφος τῆς κωπηλασίας.	It usually happens that the exhalation that is ejected is inflamed and burns with a thin and faint fire: this is what we call lightning, where we see as it were the exhalation coloured in the act of its ejection. It comes into existence after the collision and the thunder, though we see it earlier because sight is quicker than hearing. The rowing of triremes illustrates this: the oars are going back again before the sound of their striking the water reaches us.

Postquam philosophus determinavit de his quae generantur ex exhalatione sicca circa terram et in terra, sicut de ventis et terraemotu, hic determinat de his quae generantur ex eadem in nube. Et circa hoc duo facit: primo praemittit intentionem suam, et dicit quod determinato de vento et terraemotu restat consequenter dicendum de coruscatione et tonitruo, et de typhone, idest de vento circulari expulso ex nube, et de incensionibus et fulminibus, et simul de omnibus, quia omnium est idem principium, scilicet exhalatio sicca, et omnia etiam sunt substantialiter exhalatio, quae differt secundum motus et passiones diversas.

Deinde cum dicit: exhalatione enim etc., prosequitur intentum suum. Et circa hoc duo facit: primo praemittit quaedam necessaria ad propositum; secundo determinat de coruscatione et tonitruo secundum opinionem propriam, ibi: segregata quidem igitur et cetera. Circa primum praemittit tria. Primum est, quod sicut saepe dictum est prius, cum aqua et terra calefactae fuerint virtute solis, elevatur duplex exhalatio, una quidem humida, quae est principium pluviae, nivis et grandinis, et similium, alia autem sicca, quae est principium propositorum sicut videbitur, et etiam quorundam prius determinatorum. Et ambae illae exhalationes simul elevantur, quia nec humida nec sicca sola sine alia ascendit, sicut supra declaratum est. Secundum est, quod aggregatum ex istis duabus exhalationibus si sit humidum a praedominio, tunc propter frigiditatem convertitur in nubem, sicut dictum est in praecedentibus. Tertium est, quod nubes est densior in parte superiori quam in inferiori; et huius ratio est, quia necesse est nubem esse frigidiorem, et ex consequenti densiorem, in ea parte ubi deficit caliditas disgregans nubem; in parte autem superiori magis deficit caliditas, quia pars superior mediae regionis magis distat a puncto reflexionis: igitur ibi nubes est spissior. Sed in parte inferiori nubes est rarior, quia est minus frigida, et propterea, quia est minus densa, fulmina, Ecnephiae et omnia huiusmodi quae fiunt ex sicca exhalatione, propulsa a frigido moventur inferius, quamvis exhalatio sicca sit nata moveri sursum propter naturam caliditatis. Sicut in simili accidit, quia nuclei et parvi lapilli, dum comprimuntur inter digitos ex una parte, exeunt ex alia quae est minus compressa et densa.

Deinde cum dicit: segregata quidem igitur etc., inquirit causas et principia aliquorum propositorum, scilicet tonitrui et coruscationis, quae sunt nobis magis manifesta; sed in principio tertii libri reddit causam aliorum minus manifestorum. Circa hoc autem tria facit: primo ostendit causam et modum generationis tonitrui; secundo manifestat causam coruscationis, ibi: spiritus autem extrusus etc.; tertio comparat illa duo simul, ibi: fit autem post percussuram et cetera. Dicit ergo primo quod exhalatio calida et sicca, elevata cum vapore humido iuxta primum suppositum, quantum ad partes subtiles dispergitur in aere supra locum frigidum per virtutem calidi, sed alia pars quae est grossior, quae propter grossitiem non elevatur in altum, includitur in partibus aeris frigidi coagulantis nubem, et in nube, segregata tamen a frigiditate partium nubis. Et illa exhalatio sic in nube inclusa, propter frigiditatem nubis exitum petit, et movetur huc et illuc, et facit magnam percussionem frangendo latera nubis. Et ex tali percussione et fractione causatur sonus, qui vocatur tonitruum. Et hoc declarat per simile: quia fumus existens intra lignum viride, aliquando resolvitur et subtiliatur a calido ignis, et sic subtiliatum quaerit maiorem locum et petit exitum, et sic percutiendo lignum vel corticem per violentiam, causat diversum sonum secundum diversam dispositionem materiae et exhalationis moventis; de quo sono dicunt vulgares, fabulas et prodigia sectantes, quod est risus Vulcani, quem dicebant esse Deum ignis: alii autem dicunt quod est risus Vestae, quae secundum eos est dea ignis; aliquando etiam, cum scilicet sonus est magnus et subitus, dicunt quod est comminatio utriusque ad circumstantes. Huic etiam simile apparet in castanea non scissa, et posita ad ignem: cum enim exhalatio per calorem subtiliata exitum quaerit, tunc frangit castaneam cum magno sono. Et eodem modo exhalatio subtiliata quaerens exitum ex nube, et percutiens cum violentia latera nubis habentia spissitudinem, et frangens ea, facit sonum quem vocamus tonitruum. Causa autem diversitatis sonorum est ex diversitate percussionum et ex diversitate et irregularitate partium nubis, quarum quaedam sunt frigidiores et spissiores, propter quod fortius repercutiuntur et sonant, aliae vero sunt minus spissae, et ex hoc remissius sonant. Tonitruum igitur est sonus factus propter causam dictam, scilicet propter collisionem violentam exhalationis siccae ad latera nubis a frigido propellente.

Deinde cum dicit: spiritus autem extrusus etc., ostendit causam coruscationis. Et dicit quod eadem exhalatio sicca quae ex collisione sua causat tonitruum, extrusa et propulsata inferius secundum multas partes, ignitur debiliter in partibus subtilioribus et coloratur: sicut etiam apparet in corpore ignibili violenter ac fortiter moto, quod propter motum ignitur. Et hoc dicimus coruscationem extrusam a nube, et coloratam sive ignitam a calido igniente.

Deinde cum dicit: fit autem post percussuram etc., comparat ista duo quantum ad tempus apparitionis et generationis. Et dicit quod coruscatio secundum naturam posterius generatur quam tonitruum: quia tonitruum causatur ex violenta percussione ad latera nubis, coruscatio autem est ignitio exhalationis extrusae a nube: extrusio autem et ignitio sunt posteriores percussura. Sed quod coruscatio prius videatur quam audiatur tonitruum ideo est, quia visus in apprehendendo anticipat auditum: quia auditus indiget tempore ut sonus cum motu locali veniat ad ipsum, sed perfectio visus a visibili non est in tempore, sed in indivisibili. Et ex hoc sensus visus perfectior est auditu, ut patet in I Metaphys., quia citius et immaterialius immutatur ab obiecto. Et hoc manifestat Aristoteles in motu triremium, idest navium quae habent tres ordines remorum: quia quando remigantes elevant remos a prima percussione, prius videtur elevatio remorum quam audiatur sonus ex percussione praecedenti. Patet etiam quod in ripa Sequanae, ab existentibus de longe prius videtur elevatio percussorii lotri, cum purgant pannos, quam audiatur sonus. Et qui intuentur de longe lapidicidas, vel incidentes ligna, prius vident elevationem securis vel mallei, immo prius vident secundam percussuram, quam audiant sonum primae. Sic etiam licet tonitruum et percussura prius generetur quam coruscatio, tamen prius apparet coruscatio, quia visus praevenit auditum.

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Lectio 17

καίτοι τινὲς λέγουσιν ὡς ἐν τοῖς νέφεσιν ἐγγίγνεται πῦρ τοῦτο δ' Ἐμπεδοκλῆς μέν φησιν εἶναι τὸ ἐμπεριλαμβανόμενον τῶν τοῦ ἡλίου ἀκτίνων, Ἀναξαγόρας δὲ τοῦ ἄνωθεν αἰθέρος, ὃ δὴ ἐκεῖνος καλεῖ πῦρ κατενεχθὲν ἄνωθεν κάτω. τὴν μὲν οὖν διάλαμψιν ἀστραπὴν εἶναι τὴν τούτου τοῦ πυρός, τὸν δὲ ψόφον ἐναποσβεννυμένου καὶ τὴν σίξιν βροντήν, ὡς καθάπερ φαίνεται καὶ γιγνόμενον οὕτως καὶ πρότερον τὴν ἀστραπὴν οὖσαν τῆς βροντῆς. ἄλογος δὲ καὶ ἡ τοῦ πυρὸς ἐμπερίληψις, ἀμφοτέρως μέν, μᾶλλον δ' ἡ κατάσπασις τοῦ ἄνωθεν αἰθέρος. τοῦ τε γὰρ κάτω φέρεσθαι τὸ πεφυκὸς ἄνω δεῖ λέγεσθαι τὴν αἰτίαν, καὶ διὰ τί ποτε τοῦτο γίγνεται κατὰ τὸν οὐρανὸν ὅταν ἐπινέφελον ᾖ μόνον, ἀλλ' οὐ συνεχῶς οὕτως αἰθρίας δὲ οὔσης οὐ γίγνεται. τοῦτο γὰρ παντάπασιν ἔοικεν εἰρῆσθαι προχείρως.	However, there are some who maintain that there is actually fire in the clouds. Empedocles says that it consists of some of the sun's rays which are intercepted: Anaxagoras that it is part of the upper ether (which he calls fire) which has descended from above. Lightning, then, is the gleam of this fire, and thunder the hissing noise of its extinction in the cloud. But this involves the view that lightning actually is prior to thunder and does not merely appear to be so. Again, this intercepting of the fire is impossible on either theory, but especially it is said to be drawn down from the upper ether. Some reason ought to be given why that which naturally ascends should descend, and why it should not always do so, but only when it is cloudy. When the sky is clear there is no lightning: to say that there is, is altogether wanton.
ὁμοίως δὲ καὶ τὸ τὴν ἀπὸ τῶν ἀκτίνων θερμότητα φάναι τὴν ἀπολαμβανομένην ἐν τοῖς νέφεσιν εἶναι τούτων αἰτίαν οὐ πιθανόν καὶ γὰρ οὗτος ὁ λόγος ἀπραγμόνως εἴρηται λίαν ἀποκεκριμένον τε γὰρ ἀναγκαῖον εἶναι τὸ αἴτιον ἀεὶ καὶ ὡρισμένον, τό τε τῆς βροντῆς καὶ τῆς ἀστραπῆς καὶ τῶν ἄλλων τῶν τοιούτων, καὶ οὕτω γίγνεσθαι. τοῦτο δὲ διαφέρει πλεῖστον ὅμοιον γὰρ κἂν εἴ τις οἴοιτο τὸ ὕδωρ καὶ τὴν χιόνα καὶ τὴν χάλαζαν ἐνυπάρχοντα πρότερον ὕστερον ἐκκρίνεσθαι καὶ μὴ γίγνεσθαι, οἷον ὑπὸ χεῖρα ποιούσης ἀεὶ τῆς συγκρίσεως ἕκαστον αὐτῶν ὡσαύτως γὰρ ἐκεῖνά τε συγκρίσεις καὶ ταῦτα διακρίσεις ὑποληπτέον εἶναι, ὥστ' εἰ θάτερα τούτων μὴ γίγνεται ἀλλ' ἔστι, περὶ ἀμφοτέρων ὁ αὐτὸς (370a.) ἀρμόσει λόγος. τήν τ' ἐναπόληψιν τί ἂν ἀλλοιότερον λέγοι τις ἢ καθάπερ ἐν τοῖς πυκνοτέροις; καὶ γὰρ τὸ ὕδωρ ὑπὸ τοῦ ἡλίου καὶ τοῦ πυρὸς γίγνεται θερμόν ἀλλ' ὅμως ὅταν πάλιν συνίῃ καὶ ψύχηται τὸ ὕδωρ πηγνύμενον, οὐδεμίαν συμβαίνει γίγνεσθαι τοιαύτην ἔκπτωσιν οἵαν ἐκεῖνοι λέγουσιν. καίτοι γ' ἐχρῆν κατὰ λόγον τοῦ μεγέθους τὴν ζέσιν ποιεῖν τὸ ἐγγιγνόμενον πνεῦμα ὑπὸ τοῦ πυρός, ἣν οὔτε δυνατὸν ἐνυπάρχειν πρότερον, οὔτ' ἐκεῖνοι τὸν ψόφον ζέσιν ποιοῦσιν ἀλλὰ σίξιν ἔστι δὲ καὶ ἡ σίξις μικρὰ ζέσις ᾗ γὰρ τὸ προσπῖπτον κρατεῖ σβεννύμενον, ταύτῃ ζέον ποιεῖ τὸν ψόφον. εἰσὶ δέ τινες οἳ τὴν ἀστραπήν, ὥσπερ καὶ Κλείδημος, οὐκ εἶναί φασιν ἀλλὰ φαίνεσθαι, παρεικάζοντες ὡς τὸ πάθος ὅμοιον ὂν καὶ ὅταν τὴν θάλαττάν τις ῥάβδῳ τύπτῃ φαίνεται γὰρ τὸ ὕδωρ ἀποστίλβον τῆς νυκτός οὕτως ἐν τῇ νεφέλῃ ῥαπιζομένου τοῦ ὑγροῦ τὴν φάντασιν τῆς λαμπρότητος εἶναι τὴν ἀστραπήν.	The view that the heat of the sun's rays intercepted in the clouds is the cause of these phenomena is equally unattractive: this, too, is a most careless explanation. Thunder, lightning, and the rest must have a separate and determinate cause assigned to them on which they ensue. But this theory does nothing of the sort. It is like supposing that water, snow, and hail existed all along and were produced when the time came and not generated at all, as if the atmosphere brought each to hand out of its stock from time to time. They are concretions in the same way as thunder and lightning are discretions, so that if it is true of either that they are not generated but pre-exist, the same must be true of the other. Again, how can any distinction be made about the intercepting between this case and that of interception in denser substances such as water? Water, too, is heated by the sun and by fire: yet when it contracts again and grows cold and freezes no such ejection as they describe occurs, though it ought on their the. to take place on a proportionate scale. Boiling is due to the exhalation generated by fire: but it is impossible for it to exist in the water beforehand; and besides they call the noise 'hissing', not 'boiling'. But hissing is really boiling on a small scale: for when that which is brought into contact with moisture and is in process of being extinguished gets the better of it, then it boils and makes the noise in question. Some—Cleidemus is one of them—say that lightning is nothing objective but merely an appearance. They compare it to what happens when you strike the sea with a rod by night and the water is seen to shine. They say that the moisture in the cloud is beaten about in the same way, and that lightning is the appearance of brightness that ensues. This theory is due to ignorance of the theory of reflection, which is the real cause of that phenomenon. The water appears to shine when struck because our sight is reflected from it to some bright object: hence the phenomenon occurs mainly by night: the appearance is not seen by day because the daylight is too in, tense and obscures it.
οὗτοι μὲν οὖν οὔπω συνήθεις ἦσαν ταῖς περὶ τῆς ἀνακλάσεως δόξαις, ὅπερ αἴτιον δοκεῖ τοῦ τοιούτου πάθους εἶναι φαίνεται γὰρ τὸ ὕδωρ στίλβειν τυπτόμενον ἀνακλωμένης ἀπ' αὐτοῦ τῆς ὄψεως πρός τι τῶν λαμπρῶν. διὸ καὶ γίγνεται μᾶλλον τοῦτο νύκτωρ τῆς γὰρ ἡμέρας οὐ φαίνεται διὰ τὸ πλέον ὂν τὸ φέγγος τὸ τῆς ἡμέρας ἀφανίζειν. τὰ μὲν οὖν λεγόμενα περὶ βροντῆς τε καὶ ἀστραπῆς παρὰ τῶν ἄλλων ταῦτ' ἐστί, τῶν μὲν ὅτι ἀνάκλασις ἡ ἀστραπή, τῶν δ' ὅτι πυρὸς μὲν ἡ ἀστραπὴ διάλαμψις, ἡ δὲ βροντὴ σβέσις, οὐκ ἐγγιγνομένου παρ' ἕκαστον πάθος τοῦ πυρὸς ἀλλ' ἐνυπάρχοντος. ἡμεῖς δέ φαμεν τὴν αὐτὴν εἶναι φύσιν ἐπὶ μὲν τῆς γῆς ἄνεμον, ἐν δὲ τῇ γῇ σεισμόν, ἐν δὲ τοῖς νέφεσι βροντήν πάντα γὰρ εἶναι ταῦτα τὴν οὐσίαν ταὐτόν, ἀναθυμίασιν ξηράν, ἣ ῥέουσα μέν πως ἄνεμός ἐστιν, ὡδὶ δὲ ποιεῖ τοὺς σεισμούς, ἐν δὲ τοῖς νέφεσι μεταβάλλουσα διακρινομένη, συνιόντων καὶ συγκρινομένων αὐτῶν εἰς ὕδωρ, βροντάς τε καὶ ἀστραπὰς καὶ πρὸς τούτοις τἆλλα τὰ τῆς αὐτῆς φύσεως τούτοις ὄντα. καὶ περὶ μὲν βροντῆς εἴρηται καὶ ἀστραπῆς.	These are the theories of others about thunder and lightning: some maintaining that lightning is a reflection, the others that lightning is fire shining through the cloud and thunder its extinction, the fire not being generated in each case but existing beforehand. We say that the same stuff is wind on the earth, and earthquake under it, and in the clouds thunder. The essential constituent of all these phenomena is the same: namely, the dry exhalation. If it flows in one direction it is wind, in another it causes earthquakes; in the clouds, when they are in a process of change and contract and condense into water, it is ejected and causes thunder and lightning and the other phenomena of the same nature. So much for thunder and lightning.

Postquam philosophus determinavit de coruscatione et tonitruo secundum opinionem propriam, hic ostendit opiniones aliorum suae opinioni contrarias, et improbat eas. Circa hoc autem duo facit, secundum quod duae sunt opiniones quas ponit. Primo ergo dicit quod quidam, scilicet Empedocles et Anaxagoras, ponunt in nubibus esse aliquem ignem, qui sit causa coruscationis et tonitrui. Sed illum ignem dicebat Empedocles esse interceptum a radiis solaribus descendentibus deorsum, quos existimabat esse corpora; sed Anaxagoras dixit illum ignem esse aliquam partem aetheris, idest ignis, extrusam a superioribus: quia opinabatur superiora esse de natura ignis. Et utrique dixerunt micationem, idest illustrationem, ipsius ignis esse coruscationem; sed sonum et sixim, idest stridorem illius ignis extincti, sicut apparet in titione extincto in aqua, vocant tonitruum. Quantum autem ad comparationem eorum, dicunt quod ambo generantur secundum illum ordinem quo apparent. Sed opinio utriusque videtur irrationabilis; magis tamen irrationabilis est opinio Anaxagorae, qui dixit ignem esse interceptum per detractionem ab aethere superiori, propter duas rationes. Prima est, quia de natura ignis est ascendere et non descendere, ideo irrationabile est dicere illum ignem descendere a sua sphaera: aut saltem debebat reddere causam quare descendat, cum natus sit ascendere. Secunda ratio est, quia si ignis descendit per impossibile, non est maior ratio quare descendat uno tempore quam alio, et sic non magis descenderet tempore nubis quam serenitate existente. Similiter etiam non est probabilis opinio Empedoclis propter duas rationes. Prima, quia secundum opinionem Empedoclis eodem modo deberet fieri tonitruum in qualibet parte nubis, vel semper oporteret reponere in nube aliquod determinatum per se existens in actu, puta ignem in actu, qui sit causa illorum, et a quo separentur. Sed hoc multum differt a veritate: quia oporteret idem dicere de nive, aqua et grandine et similibus, cum ista etiam generentur in superioribus, sicut tonitruum et coruscatio; et sic, si omnia ista essent prius in actu in superioribus, non generarentur ibi, sed quasi in quadam apotheca conservarentur, et tempore quo descendunt segregarentur ab aliis: quod est derisibile. Secunda ratio est, quia si nubes inspissata interciperet ignem, eadem ratione aqua calefacta a sole vel ab igne, quando postea infrigidatur pateretur idem, interciperet ignem, et haberet eosdem effectus: quia ubi est una causa, ibi est unus et idem effectus; quod tamen non apparet. Quamvis autem verum sit, quod spiritus, idest calida exhalatio, facta ab igne in aqua, faciat aliquem fervorem, idest sonum consequentem ebullitionem, non tamen facit sixim, idest stridorem causatum ab extinctione ignis. Illi autem non dicunt quod ille ignis faciat fervorem vel ebullitionem, sed sixim, idest stridorem. Est autem differentia inter ebullitionem et sixim, quia ebullitio causatur in frigido humido a calido evaporante et resolvente spiritum, sed sixis causatur a frigido calidum extinguente, vel est sonus consequens ipsum; quamvis et sixis videatur esse quaedam parva ebullitio: quia in qua parte inciderit ignis qui extinguitur, illam partem parvo tempore ebullire facit, et causat sonum. Est autem hoc quod dicitur de extinctione ignis in nube, manifeste contra experientiam sensus. Si enim ille ignis extingueretur in nube, et ex hoc causaret tonitruum, coruscatio non appareret nobis tam manifeste ignita, sed extincta: sicut titio extinctus in aqua et extractus non videtur incensus.

Secundo ibi: sunt autem quidam etc., ponit secundam opinionem, et reprobat eam. Dicit ergo quod quidam fuerunt, qui dixerunt coruscationem non esse aliquod reale, sed phantasiam et apparentiam quandam; sicut dixit Clidemus, qui probabat hoc per simile de illo, qui de nocte percutit supra mare: tunc enim apparet in mari ex aqua elevata quidam fulgor sicut in igne. Et ita similiter etiam dicebant, quod in nube velociter mota a vento vel aliquo huiusmodi, apparet quidam fulgor, quem dixerunt esse coruscationem; ex percussione autem nubis dixerunt causari tonitruum. Hanc autem opinionem reprobat philosophus, et dicit quod antiqui dixerunt hoc, quia nondum erant bene assueti scientiae de refractionibus radiorum, quae videtur esse causa immutationis apparentis in aqua percussa. Cum enim percutitur aqua et aliqualiter elevatur aliqua pars eius, visus ab ipsa refrangitur ad aliquod corpus fulgidum. In puncto autem reflexionis apparet color, mixtus ex colore corporis fulgentis et aquae a qua fit refractio: et ideo magis apparet de nocte quam de die, quia lumen solis ratione magnitudinis obumbrat illam apparitionem. Sed ista causa non potest esse in apparitione coruscationis. Deinde recolligit ea quae dicta sunt de coruscatione et tonitruo, tam secundum opinionem aliorum quam propriam: et omnia sunt clara in littera. Deinde addit quod omnia ista, scilicet ventus, terraemotus, tonitruum et coruscatio, sunt idem secundum substantiam, quia omnia sunt exhalatio sicca: quae quidem lateraliter mota et fluens circa terram, est ventus, sed propulsa infra terram et ibi angustiam passa, est terraemotus, in nubibus autem subtiliata, et propulsa a frigido quando nubes congregantur in aquam, facit tonitruum, coruscationem, et cetera quae sunt eiusdem generis. Sicut enim omnia quae generantur ex vapore humido per coagulationem a frigido, sunt idem secundum speciem, differentia secundum magis et minus et secundum diversas passiones vel diversos modos patiendi, sic etiam omnia quae generantur ex sicca exhalatione a calido inflammante vel frigido propellente, sunt idem secundum speciem, sed differunt secundum quod diversimode patiuntur a calido secundum plus et minus, et secundum diversam repulsionem a frigido. Considerandum tamen est, quod terraemotus, tonitruum, coruscatio et alia huiusmodi, dupliciter considerari possunt. Primo formaliter, scilicet inquantum terraemotus est formaliter quidam motus, tonitruum est sonus factus ab exhalatione, unde et nomen sumpsit, coruscatio vero est illuminatio facta ab exhalatione incensa, etc.: et sic manifestum est quod sunt diversarum specierum. Alio modo considerantur fundamentaliter, quantum scilicet ad fundamentum essentiale ex quo talia immediate generantur: et hoc modo sunt idem secundum speciem, quia omnia immediate fiunt ex exhalatione sicca, licet diversimode et secundum diversos modos generandi, sicut superius dictum est.

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Γ
Liber 3

Lectio 1

1	1
(370b.) Περὶ δὲ τῶν ὑπολοίπων εἴπωμεν ἔργων τῆς ἐκκρίσεως ταύτης, τὸν ὑφηγημένον ἤδη τρόπον λέγοντες. τὸ γὰρ πνεῦμα τοῦτο ἐκκρινόμενον κατὰ μικρὰ μὲν καὶ σποράδην διαχεόμενον καὶ πολλάκις γιγνόμενον καὶ διαπνέον καὶ λεπτομερέστερον ὂν βροντὰς ποιεῖ καὶ ἀστραπάς ἂν δ' ἀθρόον καὶ πυκνότερον, ἧττον δ' ἐκκριθῇ λεπτόν, ἐκνεφίας ἄνεμος γίγνεται διὸ καὶ βίαιος (τὸ γὰρ τάχος τῆς ἐκκρίσεως ποιεῖ τὴν ἰσχύν). ὅταν μὲν οὖν συνακολουθήσῃ πολλὴ καὶ συνεχὴς ἔκκρισις, τὸν αὐτὸν γίγνεται τρόπον ὥσπερ ὅταν πάλιν εἰς τοὐναντίον ὁρμήσῃ τότε γὰρ ὑετὸς καὶ ὕδατος γίγνεται πλῆθος. ὑπάρχει μὲν οὖν ἄμφω δυνάμει ταῦτα κατὰ τὴν ὕλην ὅταν δὲ ἀρχὴ γένηται τῆς δυνάμεως ὁποτερασοῦν, ἀκολουθεῖ συγκρινόμενον ἐκ τῆς ὕλης ὁποτέρου ἂν ᾖ πλῆθος ἐνυπάρχον πλέον, καὶ γίγνεται τὸ μὲν ὄμβρος, τὸ δὲ τῆς ἑτέρας ἀναθυμιάσεως ἐκνεφίας.	Let us explain the remaining operations of this secretion in the same way as we have treated the rest. When this exhalation is secreted in small and scattered quantities and frequently, and is transitory, and its constitution rare, it gives rise to thunder and lightning. But if it is secreted in a body and is denser, that is, less rare, we get a hurricane. The fact that it issues in body explains its violence: it is due to the rapidity of the secretion. Now when this secretion issues in a great and continuous current the result corresponds to what we get when the opposite development takes place and rain and a quantity of water are produced. As far as the matter from which they are developed goes both sets of phenomena are the same. As soon as a stimulus to the development of either potentiality appears, that of which there is the greater quantity present in the cloud is at once secreted from it, and there results either rain, or, if the other exhalation prevails, a hurricane.
ὅταν δὲ τὸ ἐκκρινόμενον πνεῦμα τὸ ἐν τῷ νέφει ἑτέρῳ ἀντιτυπήσῃ οὕτως ὥσπερ ὅταν ἐξ εὐρέος εἰς στενὸν βιάζηται ὁ ἄνεμος ἐν πύλαις ἢ ὁδοῖς (συμβαίνει γὰρ πολλάκις ἐν τοῖς τοιούτοις ἀπωσθέντος τοῦ πρώτου μορίου τοῦ ῥέοντος σώματος διὰ τὸ μὴ ὑπείκειν, ἢ διὰ στενότητα ἢ διὰ τὸ ἀντιπνεῖν, κύκλον καὶ δίνην γίγνεσθαι τοῦ πνεύματος τὸ μὲν γὰρ εἰς τὸ πρόσθεν κωλύει προϊέναι, τὸ δ' ὄπισθεν ἐπωθεῖ, ὥστε ἀναγκάζεται εἰς τὸ πλάγιον, ᾗ οὐ κωλύεται, φέρεσθαι, καὶ οὕτως ἀεὶ τὸ ἐχόμενον, ἕως ἂν ἓν γένηται, τοῦτο δ' ἐστὶ κύκλος οὗ γὰρ μία φορὰ σχήματος, τοῦτο καὶ αὐτὸ ἀνάγκη ἓν εἶναι) ἐπί τε τῆς γῆς οὖν διὰ ταῦτα γίγνονται οἱ δῖνοι, καὶ ἐν τοῖς νέφεσιν ὁμοίως κατὰ τὴν ἀρχήν, πλὴν ὅτι, ὥσπερ, ὅταν ἐκνεφίας γίγνηται, ἀεὶ τὸ νέφος ἐκκρίνεται καὶ γίγνεται συνεχὴς ἄνεμος, οὕτως ἐνταῦθα ἀεὶ τὸ συνεχὲς ἀκολουθεῖ τοῦ νέφους διὰ δὲ πυκνότητα οὐ δυνάμενον ἐκκριθῆναι τὸ πνεῦμα ἐκ τοῦ νέφους στρέφεται μὲν κύκλῳ τὸ πρῶτον διὰ τὴν εἰρημένην αἰτίαν, κάτω δὲ φέρεται διὰ (371a.) τὸ ἀεὶ τὰ νέφη πυκνοῦσθαι, ᾗ ἐκπίπτει τὸ θερμόν. καλεῖται δ', ἂν ἀχρωμάτιστον ᾖ, τοῦτο τὸ πάθος τυφῶν, ἄνεμος ὤν, οἷον ἐκνεφίας ἄπεπτος. βορείοις δ' οὐ γίγνεται τυφῶν, οὐδὲ νιπτικῶς ἐχόντων ἐκνεφίας, διὰ τὸ πάντα ταῦτ' εἶναι πνεῦμα, τὸ δὲ πνεῦμα ξηρὰν εἶναι καὶ θερμὴν ἀναθυμίασιν. ὁ οὖν πάγος καὶ τὸ ψῦχος διὰ τὸ κρατεῖν σβέννυσιν εὐθὺς γιγνομένην ἔτι τὴν ἀρχήν. ὅτι δὲ κρατεῖ, δῆλον οὐδὲ γὰρ ἂν ἦν νιφετός, οὐδὲ βόρεια τὰ ὑγρά ταῦτα γὰρ συμβαίνει κρατούσης εἶναι τῆς ψυχρότητος.	Sometimes the exhalation in the cloud, when it is being secreted, collides with another under circumstances like those found when a wind is forced from an open into a narrow space in a gateway or a road. It often happens in such cases that the first part of the moving body is deflected because of the resistance due either to the narrowness or to a contrary current, and so the wind forms a circle and eddy. It is prevented from advancing in a straight line: at the same time it is pushed on from behind; so it is compelled to move sideways in the direction of least resistance. The same thing happens to the next part, and the next, and so on, till the series becomes one, that is, till a circle is formed: for if a figure is described by a single motion that figure must itself be one. This is how eddies are generated on the earth, and the case is the same in the clouds as far as the beginning of them goes. Only here (as in the case of the hurricane which shakes off the cloud without cessation and becomes a continuous wind) the cloud follows the exhalation unbroken, and the exhalation, failing to break away from the cloud because of its density, first moves in a circle for the reason given and then descends, because clouds are always densest on the side where the heat escapes. This phenomenon is called a whirlwind when it is colourless; and it is a sort of undigested hurricane. There is never a whirlwind when the weather is northerly, nor a hurricane when there is snow. The reason is that all these phenomena are 'wind', and wind is a dry and warm evaporation. Now frost and cold prevail over this principle and quench it at its birth: that they do prevail is clear or there could be no snow or northerly rain, since these occur when the cold does prevail.
γίγνεται μὲν οὖν τυφῶν, ὅταν ἐκνεφίας γιγνόμενος μὴ δύνηται ἐκκριθῆναι τοῦ νέφους ἔστι δὲ διὰ τὴν ἀντίκρουσιν τῆς δίνης, ὅταν ἐπὶ γῆν φέρηται ἡ ἕλιξ συγκατάγουσα τὸ νέφος, οὐ δυναμένη ἀπολυθῆναι. ᾗ δὲ κατ' εὐθυωρίαν ἐκπνεῖ, ταύτῃ τῷ πνεύματι κινεῖ, καὶ τῇ κύκλῳ κινήσει στρέφει καὶ ἀναφέρει ᾧ ἂν προσπέσῃ βιαζόμενον.	So the whirlwind originates in the failure of an incipient hurricane to escape from its cloud: it is due to the resistance which generates the eddy, and it consists in the spiral which descends to the earth and drags with it the cloud which it cannot shake off. It moves things by its wind in the direction in which it is blowing in a straight line, and whirls round by its circular motion and forcibly snatches up whatever it meets.

Postquam philosophus determinavit de tonitruo et coruscatione in fine praecedentis libri, in principio huius tertii intendit consequenter determinare de aliis, quae generantur ex eadem exhalatione sicca extrusa ex nubibus, puta de Ecnephia, typhone et huiusmodi. Et dividitur in partes duas. In prima praemittit intentionem suam, et dicit, quod postquam determinatum est de tonitruo et coruscatione, quae sunt principales passiones in aere generatae ex materia ventorum, dicendum est consequenter de residuis effectibus sive passionibus, quae sunt minus principales, scilicet de Ecnephia, typhone, incensione et fulmine, secundum modum prius inductum, scilicet accipiendo pro principio quod duplex sit exhalatio ex terra, una humida et alia sicca, et ostendendo quomodo et unde sit in ipsis principium motus et generationis.

Secundo ibi: spiritus enim hic etc., prosequitur intentum. Et dividitur in quatuor partes, secundum quod quatuor sunt passiones de quibus determinat: primo enim determinat de Ecnephia; secundo de typhone, ibi: quando autem segregatus etc.; tertio de incensione, ibi: cum autem detractus igniatur etc.; quarto determinat de fulmine, ibi: si autem in ipsa nube et cetera. Circa primum duo facit: primo ostendit quid sit principium generationis Ecnephiae; secundo ostendit causam continuitatis et magnitudinis eius, ibi: quando quidem igitur et cetera. Dicit ergo primo quod spiritus iste qui exhalatio sicca vocatur, habens partes subtiliores, fluens ex ipsa nube per interpolationem, et dispersus in multa loca, est principium tonitrui et coruscationis, sicut prius dictum est. Sed si eadem exhalatio spissior fuerit et minus subtilis, et segregetur ex nube multa simul absque interpolatione, et feratur deorsum velociter, tunc fit Ecnephias, qui est spiritus fluens ex nube secundum rectum deorsum velociter, propter velocem segregationem quae fit a magnitudine frigidi. Propter quod Ecnephias est ventus violentus: quia velocitas segregationis facit motum velocem, velox autem motus non est sine violentia; segregatur autem celeriter propter fortitudinem frigidi segregantis.

Deinde cum dicit: quando quidem igitur etc., ostendit causam multitudinis et continuitatis Ecnephiae. Et dicit quod, quando exhalatio sicca, grossa et compacta, segregatur ex nube et est multa, ita quod longo tempore una pars sequatur aliam, tunc spiritus Ecnephiae fit magnus et continuus, propter multitudinem materiae continuae exeuntis: sicut et contraria exhalatio, scilicet humida, cum movetur, et incipiunt segregari partes et cadere pluvia, si sit multa, una pars continue cadit post aliam, et fiunt magni et continui imbres. Quod autem rationabilis sit similitudo inter istas duas contrarias exhalationes, declarat per hoc quod utrumque horum est in potentia in eadem nube; quia unumquodque est in potentia in materia ex qua fit: Ecnephias autem fit ex exhalatione sicca inclusa in nube, et pluvia generatur ex vapore ipsius nubis. Et similiter utrumque fit ab eodem principio activo, scilicet a vehementi frigiditate: eadem enim frigiditas loci et nubis concernit vaporem in aquam, et expellit violenter contrariam exhalationem calidam ex nube. Propter quod etiam multoties, cum tale principium fuerit applicatum nubi in qua utrumque est in potentia, generatur utrumque simul; et si in nube fuerit maior multitudo exhalationis siccae, fit maior ventus quam pluvia; si vero e converso plus fuerit de vapore humido, generatur maior pluvia: simul tamen fiunt Ecnephiae.

Deinde cum dicit: quando autem segregatus etc., determinat de typhone. Et circa hoc duo facit: primo determinat de ipso typhone; secundo de effectu eius, ibi: fit quidem igitur et cetera. Prima iterum in tres: primo enim determinat de principio generationis eius; secundo de motu ipsius, ibi: deorsum autem fertur etc.; tertio de tempore et loco generationis eius, ibi: borealibus autem non et cetera. Circa primum duo facit: primo facit quod dictum est; secundo comparat typhonem ad Ecnephiam quantum ad generationem eorum, ibi: veruntamen quia sicut et cetera. Dicit ergo primo quod, quando spiritus inclusus in nube segregatur et expellitur a frigiditate loci et superioris partis nubis ex amplo ventre nubis per angustum exitum et parvam scissuram, et repercutitur ad aliquod corpus solidum, tunc fit quidam ventus in portis et viis flans per modum turbinis, qui dicitur typho. Et hoc fit ex eo, quod prima pars repercutitur ad terram, sive ad aliud corpus solidum, vel aliqua alia ratione impeditur anterius procedere, et revolvitur in partem subsequentem, et pars sequens continue impellit priorem. Ideo cum pars prior non possit procedere ante, quia impeditur, neque possit retroverti, quia impellitur a sequenti, involvitur in sequenti, et reflectit se ad latus ubi non invenit prohibens: et sic causat motum quasi circularem. Motus enim qui est una latio, idest unus motus localis, si non est motus rectus, scilicet sursum aut deorsum, sicut iste, oportet quod sit circularis. Sicut autem movetur prima pars, ita similiter moventur omnes subsequentes: et propter hoc fit ista revolutio super terram, quae habet principium in nubibus.

Deinde cum dicit: veruntamen quia sicut etc., comparat typhonem ad Ecnephiam. Et dicit quod similiter generantur, scilicet per continuam segregationem nubis a spiritu, sive ab exhalatione sicca; quod propterea necessarium est, quia typho velocius movetur circulariter, quam nubes nata sit ex seipsa moveri, et ex hoc nubes continue separatur ab exhalatione, ita tamen quod semper aliqua pars nubis sequitur exhalationem. Et sic etiam generatur Ecnephias; sed tamen ista duo differunt in motu: quia Ecnephias movetur motu recto, typho autem movetur secundum circulum, propter causam iam dictam.

Deinde cum dicit: deorsum autem fertur etc., determinat de motu eius. Et dicit quod typho licet sit generatus superius, tamen movetur deorsum sicut Ecnephias, quia fertur in contrarium eius a quo expellitur: expellitur autem a superiori parte nubis, quae est magis frigida, propter hoc quod ibi deficit caliditas causata a reflexione radiorum solarium, sicut supra dictum est: et ex consequenti movetur inferius. Et vocatur ille spiritus typho, quando movetur deorsum circulariter, et non est coloratus, nec a calido ignitus, sicut multae aliae impressiones; quod accidit ex hoc, quia ille spiritus est indigestus, et non est totaliter separatus a nube, sed semper trahit secum aliquam partem nubis, et eius humiditas impedit eius colorationem vel ignitionem.

Deinde cum dicit: borealibus autem etc., determinat de loco et tempore generationis typhonis. Et dicit quod typho non generatur in temporibus et locis borealibus, idest vehementer frigidis, nec etiam in locis vel temporibus nivosis et congelatis, sicut nec Ecnephias. Et huius ratio est, quia ista duo in hoc conveniunt, quod utrumque est spiritus, idest exhalatio sicca. Cum autem obtinet excellens frigus, idest quando est tempus vel locus excellentis frigoris, tunc exhalatio calida statim in sui principio extinguitur a magno frigore. Et propter eandem causam, in eisdem locis raro aut nunquam fit tonitruum et terraemotus.

Deinde cum dicit: fit quidem igitur etc., ostendit effectum mirabilem huius venti. Et dicit, quod sicut descendendo semper ducit secum aliquam partem nubis, ita quando reflectitur a terra involvit secum omnia super quae cadit, eradicando scilicet arbores, quandoque evertendo domos, elevando saxa. Et cum inciderit ad mare, elevat secum et involvit magnitudinem aquae maris: quandoque autem elevat naves, propter quod multum timetur a nautis; quia super quaecumque incidit, illa motu circulari circumeundo et vim faciendo evertit, et revertendo elevat ea sursum.

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Lectio 2

ὅταν δὲ κατασπώμενον ἐκπυρωθῇ (τοῦτο δ' ἐστὶν ἐὰν λεπτότερον τὸ πνεῦμα γένηται), καλεῖται πρηστήρ συνεκπίμπρησι γὰρ τὸν ἀέρα τῇ πυρώσει χρωματίζων.

When the cloud burns as it is drawn downwards, that is, when the exhalation becomes rarer, it is called a fire-wind, for its fire colours the neighbouring air and inflames it.

ἐὰν δ' ἐν αὐτῷ τῷ νέφει πολὺ καὶ λεπτὸν ἐκθλιφθῇ πνεῦμα, τοῦτο γίγνεται κεραυνός, ἐὰν μὲν πάνυ λεπτόν, οὐκ ἐπικάων διὰ λεπτότητα, ὃν οἱ ποιηταὶ ἀργῆτα καλοῦσιν, ἐὰν δ' ἧττον, ἐπικάων, ὃν ψολόεντα καλοῦσιν ὁ μὲν γὰρ διὰ τὴν λεπτότητα φέρεται, διὰ δὲ τὸ τάχος φθάνει διιὼν πρὶν ἢ ἐκπυρῶσαι καὶ ἐπιδιατρίψας μελᾶναι ὁ δὲ βραδύτερος ἔχρωσε μέν, ἔκαυσε δ' οὔ, ἀλλ' ἔφθασε. διὸ καὶ τὰ μὲν ἀντιτυπήσαντα πάσχει τι, τὰ δὲ μὴ οὐδέν, οἷον ἀσπίδος ἤδη τὸ μὲν χάλκωμα ἐτάκη, τὸ δὲ ξύλον οὐδὲν ἔπαθεν διὰ γὰρ μανότητα ἔφθασε τὸ πνεῦμα διηθηθὲν καὶ διελθόν καὶ δι' ἱματίων ὁμοίως οὐ κατέκαυσεν, ἀλλ' οἷον τρῦχος ἐποίησεν ὥστε ὅτι γε πνεῦμα ταῦτα πάντα, δῆλον καὶ ἐκ τῶν τοιούτων. ἔστι δ' ἐνίοτε καὶ τοῖς ὄμμασιν θεωρεῖν, οἷον καὶ νῦν ἐθεωροῦμεν περὶ τὸν ἐν Ἐφέσῳ ναὸν καόμενον πολλαχῇ γὰρ ἡ φλὸξ ἐφέρετο συνεχής, ἀποσπωμένη χωρίς. ὅτι μὲν γὰρ ὅ τε καπνὸς πνεῦμα καὶ κάεται ὁ καπνός, (371b.) φανερόν, καὶ εἴρηται ἐν ἑτέροις πρότερον ὅταν δ' ἀθρόον χωρῇ, τότε φανερῶς δοκεῖ πνεῦμα εἶναι. ὅπερ οὖν ἐν ταῖς μικραῖς πυρκαϊαῖς φαίνεται, τοῦτο καὶ τότε πολλῆς ὕλης καομένης ἐγίγνετο πολλῷ ἰσχυρότερον. ῥηγνυμένων οὖν τῶν ξύλων, ὅθεν ἡ ἀρχὴ τοῦ πνεύματος ἦν, πολὺ ἐχώρει ἀθρόον, ᾗ ἐξέπνει, καὶ ἐφέρετο ἄνω πεπυρωμένον. ὥστ' ἐφαίνετο ἡ φλὸξ φέρεσθαι καὶ εἰσπίπτειν εἰς τὰς οἰκίας. ἀεὶ γὰρ οἴεσθαι δεῖ ἐπακολουθεῖν τοῖς κεραυνοῖς πνεῦμα καὶ προϊέναι ἀλλ' οὐχ ὁρᾶται, διὰ τὸ ἀχρωμάτιστον εἶναι. διὸ καὶ ᾗ μέλλει πατάξειν, κινεῖται πρὶν πληγῆναι, ἅτε πρότερον προσπιπτούσης τῆς ἀρχῆς τοῦ πνεύματος. καὶ αἱ βρονταὶ δὲ διιστᾶσιν οὐ τῷ ψόφῳ, ἀλλ' ὅτι ἅμα συνεκκρίνεται τὸ τὴν πληγὴν ποιῆσαν καὶ τὸν ψόφον πνεῦμα ὃ ἐὰν πατάξῃ, διέστησεν, ἐπέκαυσε δ' οὔ. περὶ μὲν οὖν βροντῆς καὶ ἀστραπῆς καὶ ἐκνεφίου, ἔτι δὲ πρηστήρων τε καὶ τυφώνων καὶ κεραυνῶν, εἴρηται, καὶ ὅτι ταὐτὸ πάντα, καὶ τίς ἡ διαφορὰ πάντων αὐτῶν.

When there is a great quantity of exhalation and it is rare and is squeezed out in the cloud itself we get a thunderbolt. If the exhalation is exceedingly rare this rareness prevents the thunderbolt from scorching and the poets call it 'bright': if the rareness is less it does scorch and they call it 'smoky'. The former moves rapidly because of its rareness, and because of its rapidity passes through an object before setting fire to it or dwelling on it so as to blacken it: the slower one does blacken the object, but passes through it before it can actually burn it. Further, resisting substances are affected, unresisting ones are not. For instance, it has happened that the bronze of a shield has been melted while the woodwork remained intact because its texture was so loose that the exhalation filtered through without affecting it. So it has passed through clothes, too, without burning them, and has merely reduced them to shreds. Such evidence is enough by itself to show that the exhalation is at work in all these cases, but we sometimes get direct evidence as well, as in the case of the conflagration of the temple at Ephesus which we lately witnessed. There independent sheets of flame left the main fire and were carried bodily in many directions. Now that smoke is exhalation and that smoke burns is certain, and has been stated in another place before; but when the flame moves bodily, then we have ocular proof that smoke is exhalation. On this occasion what is seen in small fires appeared on a much larger scale because of the quantity of matter that was burning. The beams which were the source of the exhalation split, and a quantity of it rushed in a body from the place from which it issued forth and went up in a blaze: so that the flame was actually seen moving through the air away and falling on the houses. For we must recognize that exhalation accompanies and precedes thunderbolts though it is colourless and so invisible. Hence, where the thunderbolt is going to strike, the object moves before it is struck, showing that the exhalation leads the way and falls on the object first. Thunder, too, splits things not by its noise but because the exhalation that strikes the object and that which makes the noise are ejected simultaneously. This exhalation splits the thing it strikes but does not scorch it at all. We have now explained thunder and lightning and hurricane, and further firewinds, whirlwinds, and thunderbolts, and shown that they are all of them forms of the same thing and wherein they all differ.

Deinde cum dicit: cum autem detractus igniatur etc., determinat de incensione. Et dicit, quod cum spiritus subtilior quam ille ex quo generatur typho, segregatus fuerit ex nube, et ignitus propter suam subtilitatem et motum violentum calidi, tunc fit passio quae dicitur incensio. Et haec exhalatio sic incensa, cadendo coincendit aerem per quem cadit; sed quia illa incensio non est fortis sed debilis, videtur potius quaedam coloratio aeris ad modum albi.

Deinde cum dicit: si autem in ipsa etc., determinat de fulmine. Et circa hoc tria facit: primo determinat de fulmine; secundo de effectu eius, ibi: hic quidem enim etc.; tertio concludit quoddam corollarium ex dictis, ibi: quare et quod spiritus et cetera. De primo ergo dicit, quod si spiritus subtilis secundum substantiam et multus in quantitate, extrudatur a frigido quod est in ipsa nube, generatur fulmen, quod penetrat et frequenter adurit illud cui incidit. Quod quidem est duplex: nam si spiritus fuerit magis subtilis quam calidus, fit fulmen vehementer penetrans, sed non adurit; si autem exhalatio fuerit minus subtilis et magis calida, fit fulmen quod tardius penetrat, et maiorem moram faciendo adurit. Primum poetae vocant argeta, secundum vero psoloenta.

Deinde cum dicit: hic quidem enim etc., determinat de efficacia sive effectu fulminis. Et dicit quod primum fulmen, quod scilicet est magis subtile quam calidum, propter eius subtilitatem velocissime movetur, et penetrat illa super quae cadit antequam ipsa igniat, et est adeo subtile, quod penetrat intra res per parvos poros et insensibiles. Ex quo etiam ratio reddi potest multorum effectuum mirabilium, qui efficiuntur ab hoc fulmine. Aliquando enim visum est, quod ictu fulminis liquefacta est pecunia in marsupio, illaeso marsupio: et hoc propter eius magnam subtilitatem, propter quam per poros aut parva foramina, aut per os marsupii penetravit ad pecuniam, illaeso marsupio. Et simili ratione inventi sunt homines mortui a fulmine, vestimentis exterioribus illaesis; puer etiam in utero matris exterminatus est, matre remanente intacta. Dicit etiam Seneca, quod vinum quandoque sine combustione mansit, et remansit in dolio, adustis asseribus et ad terram proiectis. Et huius ratio esse potest, quia virtus penetrativa fulminis per quam confregit asseres et latera dolii, multo maior est quam virtus vini, per quam natum est effundi deorsum: ideo in minori tempore frangit latera vasis, quam vinum natum sit moveri deorsum; quapropter confracto vase vinum stare potuit per modicum tempus, maxime si sit vinum viscosum et grossum, et vas sit porosum, quia tunc facilius fulmen pertransit vas quod est porosum, quam vas in quo non inveniuntur pori. Sua etiam caliditate fulmen facit vinum grossum et viscosum, maxime in superficie facere potest quasi crustam, ut patet de sapa, propter quod vinum tardius effunditur. Sed aliud fulmen, quia est grossius, propter nimiam eius tarditatem non ita penetrat: et quia est calidius quam subtile, prius adurit et colorat quam penetret, ita quod adustio praevenit motum localem eius in penetrando. Hoc autem fulmen, quia propter suam grossitiem non multum penetrat, ideo minus laedit dura et resistentia quam rara. Unde aliquando inventum est, quod excussit aliquando vestem, aliquando pilos et barbam hominis, homine in nullo penitus laeso. Sed primum fulmen ea quae parum resistunt non colorat aut adurit, sed cito penetrat, sicut prius dictum est. Ea vero quae resistunt, ut sunt corpora dura, magis patiuntur ab hoc fulmine, quia ea adurit propter duas rationes; primo quia ea quae sustinent fixionem fulminis maiori tempore, magis patiuntur ab eo: sed fulmen agit in resistentia maiori tempore; secundo quia quando resistitur spiritui, tunc spiritus fortificatur et multiplicatur et fortius agit. Et hoc etiam manifestat duobus exemplis. Primo quia visum est quandoque, quod clypeus a parte interiori erat coopertus aere in aliqua parte, vel etiam a parte exteriori, et iste clypeus ictus fulmine et lignum nihil passum fuit, quia propter raritatem cito ipsum penetravit fulmen, sed aes, quod magis resistebat, liquefactum fuit. Temporibus etiam nostris miles, qui percussus est a fulmine, habebat scutum ligneum suspensum humeris, et sub scuto arma ferrea: fulmen confregit et partim liquefecit ferrum sub scuto, lignum autem scuti in nullo laesum inventum est. Secundo dicit, quod sicut dictum est, fulmen aliquando interfecit hominem propter resistentiam, vestimenta vero propter minorem resistentiam pertransivit. Ex quo concludi potest, quod primum fulmen magis periculosum est quam secundum. Si autem verum sit quod fulmen habet alios effectus, qui proferuntur vulgo, ut puta quod magis percutiunt campanilia Ecclesiae et loca sacra quam alia loca, dicendum quod non est inconveniens, quod Daemones utantur virtute sua circa hos mirabiles effectus naturae, ut ipsi rerum mirabilium auctores videantur: sicut aliquando se immiscent nobilissimo effectui naturae, scilicet generationi et propagationi humanae. Nos tamen hic non quaerimus quid Deus permittat, sed quid natura faciat. Et de facili dicere possumus, quod magis tangit campanilia et Ecclesias, quia sunt altiores, et citius ei occurrunt. Sciendum est etiam quod Seneca tres species fulminis dicit esse; sed istae de facili reducuntur ad duas praedictas, ut patet intuenti.

Deinde cum dicit: quare et quod spiritus etc., concludit corollarie ex dictis, quod fulmen non est lapis vel aliquod corpus solidum, sicut tamen multi crediderunt, sed est spiritus, idest exhalatio sicca, incensa et subtilis. Et hoc quod dicit philosophus, declarat per ea quae patent oculis; quia combusto templo in Epheso a fulmine, ibi, quia materia fulminis erat multa, videri poterat quod fulmen est spiritus: quia quando templum percussum est, flamma exhalationis incensae ferebatur hac illac ad multas partes templi, et denique cum fumo templi ferebatur sursum, incensa sicut fumus propter admixtionem humidi grossi quod exibat ex combustione templi. Sed accidit de huiusmodi exhalatione sicut de fumo, quia etiam fumus est quidam spiritus, et ardet sicut exhalatio, sicut prius dictum est. Quando igitur materia est multa quae comburitur, tunc fit multus fumus incensus, et manifeste videtur, sicut in incensione fornacis: quando autem materia est pauca, non ita videtur fumus. Sic etiam quando materia fulminis est multa, manifeste apparet quod fulmen est exhalatio incensa, sicut accidit in fulmine percutiente praedictum templum: quando vero materia est pauca, non ita videtur; quod tamen videtur in uno, iudicandum est etiam in altero. Quod autem fulmen non sit corpus solidum vel lapis, patet: quia tale corpus non potest habere effectus, qui superius dicti sunt procedere a fulmine. Non enim posset penetrare ad interiora, nisi prius ruptis exterioribus: alioquin duo corpora essent simul in eodem loco, quod naturaliter non potest fieri. Videtur etiam inconveniens esse, quod tam parvus lapis evertat turres et domos. Considerandum tamen est, quod quandoque cum fulmine antefertur lapis vel aliud huiusmodi deorsum, quod vel est generatum in nube ab exhalatione calida, digerente humidum aqueum nubis, sicut patet in decoctione laterum: qui lapis etiam quandoque antefertur tonitruo, vel a vento circulari sursum est elevatum. Sed iste lapis non est fulmen, ut dictum est, neque semper fit quando fit fulmen.

Deinde cum dicit: semper enim oportet etc., reddit rationem cuiusdam accidentis circa fulmen, quare scilicet illa quae percutiuntur a fulmine, videntur moveri antequam percutiantur. Et huius ratio est sicut ipse dicit, quia aliquis spiritus, velut fumus vel aer motus ab ipso fulmine, semper praecedit et semper sequitur exhalationem incensam, quae est fulmen: qui spiritus propulsus ante fulmen suo motu movet corpora, quae patiuntur a fulmine. Et propter hanc causam animalia fulmine percussa ut in pluribus inveniuntur habere caput conversum ad fulmen, quia sentientes hunc motum qui praecedit fulmen, naturaliter convertunt caput ad illam partem, ut cognoscant quid sit, et sic percutiuntur fulmine.

Deinde cum dicit: et tonitrua autem etc., comparat fulmen ad tonitruum. Et dicit, quod sicut fulmen deiicit et dividit corpora quae tangit, ita similiter tonitruum quandoque dividit corpora. Sed tamen non est imaginandum quod tonitruum dividat corpora mediante sono, sed dividit mediante spiritu, idest exhalatione segregata a nube, quae incidens alicui corpori plerumque dividit illud, sed non exurit, quia non est ita subtilis et incensa sicut fulmen. Ipsum vero fulmen dividit mediante motu exhalationis, exurit autem et colorat propter ignitionem. Deinde recapitulat ea quae dicta sunt, dicens quod de tonitruo et coruscatione et Ecnephia, iterum de typhonibus et incensione et fulminibus dictum est quid sit unumquodque eorum secundum substantiam: quia sunt exhalatio sicca. Sed differentia eorum est secundum magis et minus subtile, et secundum alia accidentia consequentia.

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Lectio 3

2	2
περὶ δὲ ἅλω καὶ ἴριδος, τί τε ἑκάτερον καὶ διὰ τίν' αἰτίαν γίγνεται, λέγωμεν, καὶ περὶ παρηλίων καὶ ῥάβδων καὶ γὰρ ταῦτα γίγνεται πάντα διὰ τὰς αὐτὰς αἰτίας ἀλλήλοις. πρῶτον δὲ δεῖ λαβεῖν τἂ πάθη καὶ τὰ συμβαίνοντα περὶ ἕκαστον αὐτῶν. τῆς μὲν οὖν ἅλω φαίνεται πολλάκις κύκλος ὅλος, καὶ γίγνεται περὶ ἥλιον καὶ σελήνην καὶ περὶ τὰ λαμπρὰ τῶν ἄστρων, ἔτι δ' οὐδὲν ἧττον νυκτὸς ἢ ἡμέρας καὶ περὶ μεσημβρίαν ἢ δείλην ἕωθεν δ' ἐλαττονάκις καὶ περὶ δύσιν. τῆς δ' ἴριδος οὐδέποτε γίγνεται κύκλος οὐδὲ μεῖζον ἡμικυκλίου τμῆμα καὶ δύνοντος μὲν καὶ ἀνατέλλοντος ἐλαχίστου μὲν κύκλου, μεγίστη δ' ἡ ἁψίς, αἰρομένου δὲ μᾶλλον κύκλου μὲν μείζονος, ἐλάττων δ' ἡ ἁψίς καὶ μετὰ μὲν τὴν μετοπωρινὴν ἰσημερίαν, ἐν ταῖς βραχυτέραις ἡμέραις, πᾶσαν ὥραν γίγνεται τῆς ἡμέρας, ἐν δὲ ταῖς θεριναῖς οὐ γίγνεται περὶ μεσημβρίαν. οὐδὲ δὴ δυοῖν πλείους ἴριδες οὐ γίγνονται ἅμα. τούτων δὲ τρίχρως μὲν ἑκατέρα, καὶ τὰ (372a.) χρώματα ταὐτὰ καὶ ἴσα τὸν ἀριθμὸν ἔχουσιν ἀλλήλαις, ἀμυδρότερα δ' ἐν τῇ ἐκτὸς καὶ ἐξ ἐναντίας κείμενα κατὰ τὴν θέσιν ἡ μὲν γὰρ ἐντὸς τὴν πρώτην ἔχει περιφέρειαν τὴν μεγίστην φοινικίαν, ἡ δ' ἔξωθεν τὴν ἐλαχίστην μὲν ἐγγύτατα δὲ πρὸς ταύτην, καὶ τὰς ἄλλας ἀνάλογον. ἔστι δὲ τὰ χρώματα ταῦτα ἅπερ μόνα σχεδὸν οὐ δύνανται ποιεῖν οἱ γραφεῖς ἔνια γὰρ αὐτοὶ κεραννύουσι, τὸ δὲ φοινικοῦν καὶ πράσινον καὶ ἁλουργὸν οὐ γίγνεται κεραννύμενον ἡ δὲ ἶρις ταῦτ' ἔχει τὰ χρώματα. τὸ δὲ μεταξὺ τοῦ φοινικοῦ καὶ πρασίνου φαίνεται πολλάκις ξανθόν. παρήλιοι δὲ καὶ ῥάβδοι γίγνονται ἐκ πλαγίας αἰεὶ καὶ οὔτ' ἄνωθεν οὔτε πρὸς τῆς γῆς οὔτ' ἐξ ἐναντίας, οὐδὲ δὴ νύκτωρ, ἀλλ' ἀεὶ περὶ τὸν ἥλιον, ἔτι δὲ ἢ αἰρομένου ἢ καταφερομένου τὰ πλεῖστα δὲ πρὸς δυσμάς μεσουρανοῦντος δὲ σπάνιον εἴ τι γέγονεν, οἷον ἐν Βοσπόρῳ ποτὲ συνέπεσε δι' ὅλης γὰρ τῆς ἡμέρας συνανασχόντες δύο παρήλιοι διετέλεσαν μέχρι δυσμῶν.	Let us now explain the nature and cause of halo, rainbow, mock suns, and rods, since the same account applies to them all. We must first describe the phenomena and the circumstances in which each of them occurs. The halo often appears as a complete circle: it is seen round the sun and the moon and bright stars, by night as well as by day, and at midday or in the afternoon, more rarely about sunrise or sunset. The rainbow never forms a full circle, nor any segment greater than a semicircle. At sunset and sunrise the circle is smallest and the segment largest: as the sun rises higher the circle is larger and the segment smaller. After the autumn equinox in the shorter days it is seen at every hour of the day, in the summer not about midday. There are never more than two rainbows at one time. Each of them is three-coloured; the colours are the same in both and their number is the same, but in the outer rainbow they are fainter and their position is reversed. In the inner rainbow the first and largest band is red; in the outer rainbow the band that is nearest to this one and smallest is of the same colour: the other bands correspond on the same principle. These are almost the only colours which painters cannot manufacture: for there are colours which they create by mixing, but no mixing will give red, green, or purple. These are the colours of the rainbow, though between the red and the green an orange colour is often seen. Mock suns and rods are always seen by the side of the sun, not above or below it nor in the opposite quarter of the sky. They are not seen at night but always in the neighbourhood of the sun, either as it is rising or setting but more commonly towards sunset. They have scarcely ever appeared when the sun was on the meridian, though this once happened in Bosporus where two mock suns rose with the sun and followed it all through the day till sunset.
τὰ μὲν οὖν περὶ ἕκαστον αὐτῶν συμβαίνοντα ταῦτ' ἐστίν τὸ δ' αἴτιον τούτων ἁπάντων ταὐτό πάντα γὰρ ἀνάκλασις ταῦτ' ἐστί. διαφέρουσι δὲ τοῖς τρόποις καὶ ἀφ' ὧν, καὶ ὡς συμβαίνει γίγνεσθαι τὴν ἀνάκλασιν πρὸς τὸν ἥλιον ἢ πρὸς ἄλλο τι τῶν λαμπρῶν. καὶ μεθ' ἡμέραν μὲν ἶρις γίγνεται, νύκτωρ δ' ἀπὸ σελήνης, ὡς μὲν οἱ ἀρχαῖοι ᾤοντο, οὐκ ἐγίγνετο τοῦτο δ' ἔπαθον διὰ τὸ σπάνιον ἐλάνθανε γὰρ αὐτούς γίγνεται μὲν γάρ, ὀλιγάκις δὲ γίγνεται. τὸ δ' αἴτιον ὅτι τ' ἐν τῷ σκότει λανθάνει τὰ χρώματα, καὶ ἄλλα πολλὰ δεῖ συμπεσεῖν, καὶ ταῦτα πάντα ἐν ἡμέρᾳ μιᾷ τοῦ μηνός ἐν τῇ πανσελήνῳ γὰρ γενέσθαι ἀνάγκη τὸ μέλλον ἔσεσθαι, καὶ τότε ἀνατελλούσης ἢ δυνούσης διόπερ ἐν ἔτεσιν ὑπὲρ τὰ πεντήκοντα δὶς ἐνετύχομεν μόνον.	These are the facts about each of these phenomena: the cause of them all is the same, for they are all reflections. But they are different varieties, and are distinguished by the surface from which and the way in which the reflection to the sun or some other bright object takes place. The rainbow is seen by day, and it was formerly thought that it never appeared by night as a moon rainbow. This opinion was due to the rarity of the occurrence: it was not observed, for though it does happen it does so rarely. The reason is that the colours are not so easy to see in the dark and that many other conditions must coincide, and all that in a single day in the month. For if there is to be one it must be at full moon, and then as the moon is either rising or setting. So we have only met with two instances of a moon rainbow in more than fifty years.
ὅτι μὲν οὖν ἡ ὄψις ἀνακλᾶται, ὥσπερ καὶ ἀφ' ὕδατος, οὕτω καὶ ἀπὸ ἀέρος καὶ πάντων τῶν ἐχόντων τὴν ἐπιφάνειαν λείαν, ἐκ τῶν περὶ τὴν ὄψιν δεικνυμένων δεῖ λαμβάνειν τὴν πίστιν, καὶ διότι τῶν ἐνόπτρων ἐν ἐνίοις μὲν καὶ τὰ σχήματα ἐμφαίνεται, ἐν ἐνίοις δὲ τὰ χρώματα μόνον τοιαῦτα δ' ἐστὶν ὅσα (372b.) μικρὰ τῶν ἐνόπτρων, καὶ μηδεμίαν αἰσθητὴν ἔχει διαίρεσιν ἐν γὰρ τούτοις τὸ μὲν σχῆμα ἀδύνατον ἐμφαίνεσθαι (δόξει γὰρ εἶναι διαιρετόν πᾶν γὰρ σχῆμα ἅμα δοκεῖ σχῆμά τ' εἶναι καὶ διαίρεσιν ἔχειν), ἐπεὶ δ' ἐμφαίνεσθαί τι ἀναγκαῖον, τοῦτο δὲ ἀδύνατον, λείπεται τὸ χρῶμα μόνον ἐμφαίνεσθαι. τὸ δὲ χρῶμα ὁτὲ μὲν λαμπρὸν φαίνεται τῶν λαμπρῶν, ὁτὲ δέ, ἢ τῷ μείγνυσθαι τῷ τοῦ ἐνόπτρου ἢ διὰ τὴν ἀσθένειαν τῆς ὄψεως, ἄλλου χρώματος ἐμποιεῖ φαντασίαν. ἔστω δὲ περὶ τούτων ἡμῖν τεθεωρημένον ἐν τοῖς περὶ τὰς αἰσθήσεις δεικνυμένοις διὸ τὰ μὲν λέγωμεν, τοῖς δ' ὡς ὑπάρχουσι χρησώμεθα αὐτῶν.	We must accept from the theory of optics the fact that sight is reflected from air and any object with a smooth surface just as it is from water; also that in some mirrors the forms of things are reflected, in others only their colours. Of the latter kind are those mirrors which are so small as to be indivisible for sense. It is impossible that the figure of a thing should be reflected in them, for if it is the mirror will be sensibly divisible since divisibility is involved in the notion of figure. But since something must be reflected in them and figure cannot be, it remains that colour alone should be reflected. The colour of a bright object sometimes appears bright in the reflection, but it sometimes, either owing to the admixture of the colour of the mirror or to weakness of sight, gives rise to the appearance of another colour. However, we must accept the account we have given of these things in the theory of sensation, and take some things for granted while we explain others.

Postquam philosophus determinavit de his quae generantur ex exhalatione elevata a terra per motum et alterationem, consequenter intendit determinare de his quae fiunt per refractionem luminis ab exhalatione humida constante superius. Et circa hoc duo facit. Primo ponit intentionem suam, et dicit quod cum superius determinatum sit de his quae fiunt ex exhalatione humida per motum et alterationem, consequenter dicendum est de his quae fiunt per refractionem luminis ab eodem vapore humido, consistente in nube vel caligine, puta de halo, iride et virgis, et pareliis. Et circa hoc considerandum est quid sit unumquodque eorum, et propter quam causam fiunt, quia unumquodque eorum fit propter eandem causam.

Secundo ibi: ipsius quidem igitur etc., prosequitur intentum. Et circa hoc duo facit: primo determinat in generali de accidentibus et causis halo et iridis, et quorundam aliorum quae fiunt per refractionem luminis; secundo determinat de causa et principio illorum magis in speciali, ibi: quod quidem igitur visus et cetera. Prima iterum dividitur in duas partes: primo enumerat accidentia circa halo et iridem; secundo determinat de causis dictarum apparentiarum, ibi: causa autem horum et cetera. Circa primum duo facit: primo determinat de accidentibus halo; secundo de accidentibus iridis, ibi: iridis autem nunquam et cetera. Primo ergo dicit quod halo saepius apparet secundum circulum perfectum: dicit autem saepe, quia quandoque propter interruptionem caliginis a qua fit refractio, circulus interrumpitur. Fit etiam halo circa solem et lunam, et circa astra multum luminis habentia. Adhuc non minus apparet de nocte circa lunam et stellas, quam de die circa solem: immo magis apparet de nocte quam de die, quia in die lumen solis obscurat apparentiam eius. Et indifferenter fit in meridie et in sero, sed in mane et circa occasum minus fit. Vocat autem hic philosophus occasum, non illud tempus vespertinum quod communiter sero dicitur: alias sibi contradiceret, dicendo quod halo fit in sero et non fit circa occasum; sed vocat occasum declinationem solis a meridie, quae est ante illud tempus vespertinum et post meridiem. Et non fit halo circa occasum, quia tunc propter moram solis calor est ferventior, et dissipat eius apparentiam.

Deinde cum dicit: iridis autem nunquam etc., ostendit accidentia circa alias apparentias. Et circa hoc duo facit: primo ostendit accidentia circa iridem; secundo accidentia circa virgas et parelios, ibi: parelii autem et cetera. Circa primum tria facit: primo ostendit accidentia iridis quantum ad figurationem; secundo ostendit accidentia quantum ad tempus apparitionis, ibi: et post autumnale etc.; tertio quantum ad colores et numerum, ibi: neque duabus plures et cetera. Dicit ergo primo quod iris nunquam apparet secundum circulum perfectum, neque apparet in maiori portione circuli decisi per diametrum, sed sole oriente aut occidente apparet sub figura semicirculi completa, quae est maior portio circuli sub qua possit apparere; ille tamen circulus est minor quam circulus quem facit in meridie. Cum autem sol elevatur supra horizontem, apparet minor pars semicirculi; circulus tamen quem tunc facit, est maior quam ille quem faciebat oriente vel occidente sole.

Deinde cum dicit: et post autumnale etc., enumerat accidentia iridis quantum ad tempus apparitionis. Et dicit quod post aequinoctium autumnale existentibus diebus brevioribus, iris potest apparere in qualibet hora diei, quia tunc sol non multum elevatur super horizontem: sed in aestate, sole existente circa tropicum, non fit in meridie. Et hoc maxime in regionibus, in quibus sol multum accedit ad Zenith capitum: quia tunc basis pyramidis sub qua videtur iris, aut directe iacet supra terram, aut modica portio eius est per eam. Et tunc ad videndam apparentiam iridis, oporteret quod homo iaceret quasi resupinus in terra, et oculus non esset elevatus.

Deinde cum dicit: neque duabus plures etc., ostendit quot sint irides secundum numerum, et accidentia eius quantum ad colores. Et dicit de primo quod aliquando videntur duae irides (sed plures duabus non apparent nisi raro), quarum altera continet alteram. Et utraque earum habet tres colores principales, eosdem quidem secundum speciem et aequales secundum numerum, sed eius quae est extra et continet aliam, colores sunt obscuriores et minus apparentes quam illius quae est intra et continetur. Et isti colores secundum situm sunt positi modo contrario; quia iris interior et quae continetur, habet in maiori peripheria, idest circumferentia, colorem puniceum, in media autem viridem, et in minori halurgum, idest subalbum: sed maior exterior habet in minori circulo puniceum, et alios proportionaliter, scilicet in medio viridem, et in supremo halurgum. Et hi colores, quos dicimus esse in iride, sunt tales quod eos non possunt facere pictores: ipsi enim faciunt colores per admixtionem aliorum colorum, sed isti tres colores quos habet iris, non fiunt per aliquam commixtionem.

Deinde cum dicit: parelii autem etc. determinat de accidentibus circa virgas et parelios. Et dicit quod parelii et virgae apparent tantum circa solem, et ideo non fiunt nocte, sole existente sub nostro hemisphaerio. Et quando contingit eos apparere, tunc solum apparent ex latere solis, scilicet ex parte Septentrionis vel meridiei: et non apparent supra solem, quia impressiones existentes supra solem non essent visibiles. Neque apparent directe subtus solem versus terram, neque ex opposito, puta in oriente unde movetur sol, vel in occidente ad quem tendit. Et iterum apparent parelii sole ascendente ab oriente, vel descendente ad occidentem: sed raro apparent ipso existente in meridie, quia tunc sol propter nimium calorem dissolvit materiam. Accidit tamen aliquando in Bosphoro, quod est mare dividens Asiam ab Europa, quod ibi apparuerunt duo parelii ex duobus lateribus solis, ab ortu eius usque ad occasum per totam diem. Accidentia igitur manifesta circa unumquodque istorum sunt haec quae determinata sunt.

Deinde cum dicit: causa autem horum etc., determinat de causis dictarum impressionum. Et dicit quod causa et principium omnium praedictorum est una et eadem secundum substantiam, quia omnia secundum substantiam sunt refractio. Quod intelligendum est non formaliter, sed causaliter: non enim istae impressiones sunt formaliter refractio, quia iris formaliter est quaedam figura etc., sed sunt refractio causaliter, quia omnia causantur ex refractione aliqua; sed differenter fiunt secundum diversos modos refractionis sive reflexionis ad solem vel ad aliquod aliud astrorum fulgidorum. Sed qualis fit refractio, et qualiter fiat, et ad quid, et a quo, et quae sit causa eorum quae accidunt circa ipsam refractionem, consequenter ostendit philosophus, licet textus nostri communiter hoc non habeant. Dicit ergo quod radii visuales refranguntur ab omnibus corporibus quae habent aliquam virtutem opaci, quod impedit illuminationem secundum directum, et ab habentibus planam et lenem superficiem, sicut est aqua quae est grossior, et aer qui est subtilior. Et illud quod refrangitur secundum veritatem, est lumen generatum a corpore lucido secundum directum, sed colores qui movent perspicuum quando est illuminatum, colorant ipsum.

Deinde cum dicit: et per diem quidem etc., regreditur ad numerandum quaedam alia accidentia circa iridem. Ex quo patet quod haec pars continuari debet ad illam partem in qua enumerat alia accidentia iridis: sed est huc transposita propter aliquod accidens. Dicit igitur quod iris de die apparet, propter refractionem luminis solis a nube rorida sibi opposita. Sed de nocte dixerunt quidam antiquorum ipsam non apparere per refractionem luminis: quia in nocte raro fit, propter quod latebat ipsos. Sunt autem tres causae propter quas raro apparet de nocte. Prima est, quia colores obscurantur de nocte propter obscuritatem noctis. Secunda causa est, quia iris non potest apparere neque fieri de nocte, nisi solum in uno die naturali mensis. Tertia est, quia iris non fit de nocte nisi luna existente plena in oriente, et in occidente nube opposita existente densa. Et illa raro simul contingunt. Signum autem rarae apparitionis eius dicit esse, quia in quinquaginta annis non percepit eam nisi bis fieri.

Deinde cum dicit: quod quidem igitur etc., postquam philosophus determinavit de causis praedictorum in generali, determinat de eis magis in speciali. Et dividitur in partes duas: in prima praemittit quasdam suppositiones necessarias ad propositum; secundo declarat intentum, ibi: primo autem de figura et cetera. Circa primum ergo dicit, quod oportet supponere aliqua. Et primo, quod radii visuales procedentes ab oculo, refranguntur ab aliquo prohibente eorum directam alterationem propter grossitiem, sicut ab aqua, et aere ingrossato propter humiditatem et frigiditatem, et universaliter ab omnibus corporibus grossis habentibus planam et lenem superficiem, propter quam uniformiter recipiuntur et refranguntur ad aliquod corpus lucidum. Secundo supponere oportet, quod corpora specularia a quibus fit refractio, in quibus apparet species visibilis, sunt duplicia: quaedam sunt in quibus apparet figura et color obiecti determinate, quaedam autem sunt in quibus apparent colores, non autem figura determinata, sicut sunt illa quae sunt valde parva, et non possunt dividi in partes quae comprehendantur a visu: quare relinquitur quod in talibus solus color apparebit. Tertio supponendum est, quod in corporibus specularibus aliquando apparet color clarus, quando scilicet speculum est purum et mundum, non habens aliquem colorem extraneum, et medium similiter est purum, et visus est fortis, idest bene dispositus. Aliquando autem color corporis clari apparet obscurus propter defectum alicuius istorum trium. De his autem demonstratum est in libro de sensu et sensato, vel in libro de sensu, idest in perspectiva communi: nunc autem istis suppositis dicendum est de aliis. Intelligendum est autem circa primam suppositionem, quod visio non fit extramittendo, sed intus accipiendo, idest radii visuales per quos videntur res ab extra, non procedunt ab oculo ad obiectum sed ab obiecto ad oculum. Et ideo radii visuales refranguntur a speculo ad visum, non autem ad solem vel aliud obiectum, quia non refranguntur ad id a quo procedunt. Sed Aristoteles loquitur hic secundum communem opinionem perspectivorum sui temporis, qui habebant contrariam opinionem dictis. Nec refert ad propositum, quodcumque istorum dicatur, quia eodem modo accidunt omnia circa halo et iridem, quocumque istorum posito. Ad maiorem autem claritatem dictorum et dicendorum notanda sunt duo. Primum est quod ad quamlibet refractionem tria concurrunt de necessitate: primum est obiectum quod imprimit similitudinem suam in speculum, puta lumen solis, et hoc habet rationem refracti; speculum quod determinat actionem obiecti et recipit similitudinem eius, quod habet rationem refrangentis; et visus, qui habet rationem eius ad quod fit refractio. Secundo notandum est, quod radius visualis est triplex: scilicet rectus, qui per medium uniforme libere procedit a corpore lucido ad visum; secundo reflexus, qui propter densitatem alicuius medii non potest ulterius transire, sed reflectitur et revertitur ad corpus luminosum a quo procedit: sicut accidit de radiis solaribus, qui reflectuntur a terra sursum versus solem, sicut visum est supra; tertio est radius refractus, qui propter occursum alicuius medii non quidem impeditur totaliter ulterius procedere, immo procedit usque ad visum, sed non recte, quia recedit a perpendiculari. Aristoteles tamen indifferenter utitur istis nominibus, cum dicit quod visus refrangitur ad aliquod corpus lucidum.

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Lectio 4

3	3
πρῶτον δὲ περὶ τῆς ἅλω τοῦ σχήματος εἴπωμεν, διότι τε κύκλος γίγνεται, καὶ διότι περὶ τὸν ἥλιον ἢ τὴν σελήνην, ὁμοίως δὲ καὶ περί τι τῶν ἄλλων ἄστρων ὁ γὰρ αὐτὸς ἐπὶ πάντων ἀρμόσει λόγος. γίγνεται μὲν οὖν ἡ ἀνάκλασις τῆς ὄψεως συνισταμένου τοῦ ἀέρος καὶ τῆς ἀτμίδος εἰς νέφος, ἐὰν ὁμαλὴς καὶ μικρομερὴς συνισταμένη τύχῃ. διὸ καὶ σημεῖον ἡ μὲν σύστασις ὕδατός ἐστιν, αἱ μέντοι διασπάσεις ἢ μαράνσεις, αὗται μὲν εὐδιῶν, αἱ δὲ διασπάσεις πνεύματος. ἐὰν μὲν γὰρ μήτε καταμαρανθῇ μήτε διασπασθῇ, ἀλλ' ἐαθῇ τὴν φύσιν ἀπολαμβάνειν τὴν αὑτῆς, ὕδατος εἰκότως σημεῖόν ἐστι δηλοῖ γὰρ ἤδη γίγνεσθαι τοιαύτην τὴν σύστασιν, ἐξ ἧς τὸ συνεχὲς λαμβανούσης τῆς πυκνώσεως ἀναγκαῖον εἰς ὕδωρ ἐλθεῖν διὸ καὶ μέλαιναι γίγνονται τὴν χρόαν αὗται μάλιστα τῶν ἄλλων. ὅταν δὲ διασπασθῇ, πνεύματος σημεῖον ἡ γὰρ διαίρεσις ὑπὸ πνεύματος γέγονεν ἤδη μὲν ὄντος, οὔπω δὲ παρόντος. σημεῖον δὲ τούτου διότι ἐντεῦθεν γίγνεται ὁ ἄνεμος, ὅθεν ἂν ἡ κυρία γίγνηται διάσπασις. ἀπομαραινομένη δὲ εὐδίας εἰ γὰρ μὴ ἔχει πως οὕτως ὁ ἀὴρ ὥστε κρατεῖν τοῦ ἐναπολαμβανομένου θερμοῦ μηδ' ἔρχεσθαι εἰς πύκνωσιν ὑδατώδη, δῆλον ὡς οὔπω ἡ ἀτμὶς ἀποκέκριται τῆς ἀναθυμιάσεως [ἀπὸ] τῆς ξηρᾶς καὶ πυρώδους τοῦτο δὲ εὐδίας αἴτιον.	Let us begin by explaining the shape of the halo; why it is a circle and why it appears round the sun or the moon or one of the other stars: the explanation being in all these cases the same. Sight is reflected in this way when air and vapour are condensed into a cloud and the condensed matter is uniform and consists of small parts. Hence in itself it is a sign of rain, but if it fades away, of fine weather, if it is broken up, of wind. For if it does not fade away and is not broken up but is allowed to attain its normal state, it is naturally a sign of rain since it shows that a process of condensation is proceeding which must, when it is carried to an end, result in rain. For the same reason these haloes are the darkest. It is a sign of wind when it is broken up because its breaking up is due to a wind which exists there but has not reached us. This view finds support in the fact that the wind blows from the quarter in which the main division appears in the halo. Its fading away is a sign of fine weather because if the air is not yet in a state to get the better of the heat it contains and proceed to condense into water, this shows that the moist vapour has not yet separated from the dry and firelike exhalation: and this is the cause of fine weather.
πῶς μὲν οὖν ἔχοντος τοῦ ἀέρος γίγνεται ἡ ἀνάκλασις, εἴρηται. (373a.) ἀνακλᾶται δ' ἀπὸ τῆς συνισταμένης ἀχλύος περὶ τὸν ἥλιον ἢ τὴν σελήνην ἡ ὄψις διὸ οὐκ ἐξ ἐναντίας ὥσπερ ἶρις φαίνεται. πάντοθεν δὲ ὁμοίως ἀνακλωμένης ἀναγκαῖον κύκλον εἶναι ἢ κύκλου μέρος ἀπὸ γὰρ τοῦ αὐτοῦ σημείου πρὸς τὸ αὐτὸ σημεῖον αἱ ἴσαι κλασθήσονται ἐπὶ κύκλου γραμμῆς ἀεί.	So much for the atmospheric conditions under which the reflection takes place. The reflection is from the mist that forms round the sun or the moon, and that is why the halo is not seen opposite the sun like the rainbow. Since the reflection takes place in the same way from every point the result is necessarily a circle or a segment of a circle: for if the lines start from the same point and end at the same point and are equal, the points where they form an angle will always lie on a circle.
ἔστω γὰρ ἀπὸ τοῦ σημείου ἐφ' ᾧ τὸ Α πρὸς τὸ Β κεκλασμένη ἥ τε τὸ ΑΓΒ καὶ ἡ τὸ ΑΖΒ καὶ ἡ τὸ ΑΔ Β ἴσαι δὲ αὗταί τε αἱ ΑΓ ΑΖ ΑΔ ἀλλήλαις, καὶ αἱ πρὸς τὸ Β ἀλλήλαις, οἷον αἱ ΓΒ ΖΒ ΔΒ καὶ ἐπεζεύχθω ἡ ΑΕΒ, ὥστε τὰ τρίγωνα ἴσα καὶ γὰρ ἐπ' ἴσης τῆς ΑΕΒ. ἤχθωσαν δὴ κάθετοι ἐπὶ τὴν ΑΕΒ ἐκ τῶν γωνιῶν, ἀπὸ μὲν τῆς Γ ἡ τὸ ΓΕ, ἀπὸ δὲ τῆς Ζ ἡ τὸ ΖΕ, ἀπὸ δὲ τῆς Δ ἡ τὸ ΔΕ. ἴσαι δὴ αὗται ἐν ἴσοις γὰρ τριγώνοις καὶ ἐν ἑνὶ ἐπιπέδῳ πᾶσαι πρὸς ὀρθὰς γὰρ πᾶσαι τῇ ΑΕΒ, καὶ ἐφ' ἓν σημεῖον τὸ Ε συνάπτουσι. κύκλος ἄρα ἔσται ἡ γραφομένη, κέντρον δὲ τὸ Ε. ἔστι δὴ τὸ μὲν Β ὁ ἥλιος, τὸ δὲ Α ἡ ὄψις, ἡ δὲ περὶ τὸ ΓΖΔ περιφέρεια τὸ νέφος ἀφ' οὗ ἀνακλᾶται ἡ ὄψις πρὸς τὸν ἥλιον.	Let AGB and AZB and ADB be lines each of which goes from the point A to the point B and forms an angle. Let the lines AG, AZ, AD be equal and those at B, GB, ZB, DB equal too. Draw the line AEB. Then the triangles are equal; for their base Aeb is equal. Draw perpendiculars to AEB from the angles; GE from G, Ze from Z, DE from D. Then these perpendiculars are equal, being in equal triangles. And they are all in one plane, being all at right angles to AEB and meeting at a single point E. So if you draw the line it will be a circle and E its centre. Now B is the sun, A the eye, and the circumference passing through the points GZD the cloud from which the line of sight is reflected to the sun.
δεῖ δὲ νοεῖν συνεχῆ τὰ ἔνοπτρα ἀλλὰ διὰ μικρότητα ἕκαστον μὲν ἀόρατον, τὸ δ' ἐξ ἁπάντων ἓν εἶναι δοκεῖ διὰ τὸ ἐφεξῆς. φαίνεται δὲ τὸ μὲν λευκόν, ὁ ἥλιος, κύκλῳ συνεχῶς ἐν ἑκάστῳ φαινόμενος τῶν ἐνόπτρων, καὶ μηδεμίαν ἔχων αἰσθητὴν διαίρεσιν, πρὸς δὲ τῇ γῇ μᾶλλον διὰ τὸ νηνεμώτερον εἶναι πνεύματος γὰρ ὄντος οὐκ εἶναι στάσιν φανερόν. παρὰ δὲ τοῦτο μέλαινα ἡ ἐχομένη περιφέρεια, διὰ τὴν ἐκείνης λευκότητα δοκοῦσα εἶναι μελαντέρα. πλεονάκις δὲ γίγνονται αἱ ἅλῳ περὶ τὴν σελήνην διὰ τὸ τὸν ἥλιον θερμότερον ὄντα θᾶττον διαλύειν τὰς συστάσεις τοῦ ἀέρος. περὶ δὲ τοὺς ἀστέρας γίγνονται μὲν διὰ τὰς αὐτὰς αἰτίας, οὐ σημειώδεις δ' ὁμοίως, ὅτι μικρὰς πάμπαν ἐπιδηλοῦσι τὰς συστάσεις καὶ οὔπω γονίμους.	The mirrors must be thought of as contiguous: each of them is too small to be visible, but their contiguity makes the whole made up of them all to seem one. The bright band is the sun, which is seen as a circle, appearing successively in each of the mirrors as a point indivisible to sense. The band of cloud next to it is black, its colour being intensified by contrast with the brightness of the halo. The halo is formed rather near the earth because that is calmer: for where there is wind it is clear that no halo can maintain its position. Haloes are commoner round the moon because the greater heat of the sun dissolves the condensations of the air more rapidly. Haloes are formed round stars for the same reasons, but they are not prognostic in the same way because the condensation they imply is so insignificant as to be barren.

Deinde cum dicit: primo autem de figura etc., praemissis suppositionibus necessariis ad declarationem tam dictorum quam dicendorum, consequenter prosequitur de halo, iride et reliquis. Et primo determinat de halo; secundo de iride, ibi: iris autem etc.; et tertio de pareliis et virgis, ibi: easdem autem dictas et cetera. Circa primum duo facit: primo assignat causam generationis et modum; secundo reddit causam cuiusdam accidentis halo, ibi: saepius autem et cetera. Prima iterum in tres: primo ostendit modum generationis halo; secundo ostendit causam figurae eius, ibi: undique autem etc.; tertio ostendit causam coloris illius, ibi: oportet autem et cetera. Quantum ad primum igitur primo praemittit intentionem suam. Et dicit quod primo dicendum est de halo et de figura eius in speciali, quare scilicet fit circularis figurae, et utrum fiat circa solem et lunam, et similiter circa alia astra, et non ex opposito vel ex latere alicuius: quia eadem est ratio de omnibus.

Secundo ibi: fit quidem igitur etc., quia halo apparet ex refractione visus consistente vapore vel aere, ideo philosophus declarat, quomodo se habeat vapor huiusmodi a quo fit refractio. Et dicit quod refractio visus in apparitionibus halo fit a vapore vel aere, idest ab aere vaporoso, ingrossato a frigido in nubem tenuem parvarum et regularium partium. Et hoc manifestat per signum: quia si ille vapor in quo apparet halo, ingrossetur, tunc est signum pluviae; si autem distrahatur et disgregetur, tunc est signum venti; si vero evanescat et exterminetur, tunc est signum serenitatis. Probat autem primum: quia talis ingrossatio vaporis ostendit continuam inspissationem nubis, quam tandem necessarium est permutari in aquam; et propter hoc huiusmodi nubes continue fiunt nigriores, quoadusque finaliter dispareat halo. Secundum vero manifestatur: quia illa distractio non potest fieri nisi a vento, qui iam incipit flare. In signum cuius, quando distrahitur halo, ventus incipit manifeste apparere ex illa parte in qua incoepit illa distractio; ex quo possumus etiam concludere, quod ventus prius flabat, et distrahebat halo, sed nondum erat nobis praesens et manifestus: vel prius flabat in aliis partibus, sed nondum erat praesens illi parti in qua fit halo. Marcefacta autem sive evanescens est signum serenitatis: quia non distrahitur nisi a calido disgregante vaporem nubis, et sic aer vel vapor propter tale calidum non potest condensari in nubem, ex quo fit serenitas. Unde relinquitur, quod halo fiat in nube tenui et densata a frigido, ut dictum est.

Deinde cum dicit: refrangitur autem a consistente etc., ostendit quomodo et qualiter se habente nube secundum positionem ad astrum fulgidum, fiat refractio. Et dicit quod visus refrangitur a caligine existente inter ipsum et solem vel lunam, et propter hoc non apparet ex opposito, sicut iris, quae apparet in nube opposita soli vel lunae, visu existente in medio, nec etiam apparet ex lateribus, sicut virgae et parelii. Ad cuius intelligentiam considerandum est, quod in apparitione halo inter visum et astrum mediat nubes tenuis, a qua fit refractio, ita quod astrum videtur per ipsam; propter quod etiam videtur in eadem superficie cum ipsa: quia quando aliquod corpus remotum videtur per aliquod corpus medium distans a visu, tunc obiectum videtur esse simul cum medio, quia visus propter distantiam improportionatam sibi non diiudicat remotionem unius ab altero. Et propter eandem causam corpus sphaericum a remotis visum semper apparet planae superficiei, quia visus propter improportionatam distantiam, sicut dictum est, non diiudicat distantiam, neque figuram et maximum circulum eius. pDeinde cum dicit: undique autem similiter etc., ostendit quae sit figura halo. Et dicit quod nube sic se habente ut dictum est, necesse est quod talis refractio fiat secundum circulum; et ideo necesse est halo esse circulum, si nubes sit continua et regularis, vel partem circuli si nubes sit discontinua et irregularis. Quod quidem facile est probare, si supponamus secundum veritatem quod refrangatur obiectum, non visus. Nam visibile producit radios suos pyramidaliter: cuius pyramidis basis est in ipso obiecto, conus vero pyramidis terminatur ad visum si radii sint recti, vel si sint refracti conus est in puncto refractionis, licet sit magis obtusus; in fine autem pyramidis semper apparet figura similis obiecto, sicut experientia testatur. Tum etiam, quia omne agens naturaliter imprimit suam similitudinem in passum secundum esse perfectum, nisi impediatur; cum igitur astrum sit circularis figurae, eius similitudo impressa tum in caligine tum etiam in oculo, erit figurae circularis. Sed Aristoteles hic non accipit astrum in alterando refrangi, sed visum, sicut dictum est prius, non quidem secundum radium perpendicularem, sed secundum radios declinantes a perpendiculari. Assumptum vero sic probat per rationem mathematicalem. Radii qui aequaliter distant a perpendiculari, et refranguntur ad angulos aequales, facientes scilicet angulos aequales in puncto refractionis, faciunt figuram circularem; sed radii quibus videtur halo, aequaliter distant a perpendiculari, et refranguntur in aequali distantia ad perpendicularem ad angulos aequales; ergo faciunt circulum. Maior est manifesta: quia astrum aequaliter agit et illuminat partes existentes inter extremos radios refractos, quia aequaliter distant. Minorem vero probat in terminis communibus hoc modo. Sit a visus qui refrangitur, b autem sit astrum ad quod fit refractio secundum antiquos, et protrahatur linea perpendicularis ab a in b per medium caliginis refrangentis visum, in puncto c, et signentur tria puncta aeque distantia a c in peripheria, sive circumferentia, nubis, scilicet g d z, in quibus franguntur radii luminosi ad lineam perpendicularem, et concurrunt in puncto a. Tunc ibi intelliguntur tres trianguli maiores, scilicet agb, adb et azb, qui sunt aequales, ut potest practicari per propositiones mathematicas, et maxime per quartam primi Euclidis: quae dicit quod duorum triangulorum, quorum duo latera unius sunt aequalia duobus lateribus alterius, et duo anguli duobus angulis, toti trianguli erunt aequales. Ducantur igitur tres lineae perpendiculares super lineam ab ad punctum c ab illis tribus punctis g d z in peripheria nubis signatis: tunc constituuntur tres parvi trianguli, scilicet agc, adc et azc, et isti trianguli etiam sunt aequales, sicut probari potest per eandem quartam, et per octavam primi Euclidis. Sed istae tres lineae ducuntur directe ex diversis partibus in eundem punctum, et sunt plures quam duae: igitur talis punctus est centrum circuli, et linea tangens extremitates illarum linearum erit circulus, ut dicit vigesimatertia propositio tertii Euclidis. Et ista magis patebunt in sequenti figura. (Figura).

Deinde cum dicit: oportet autem intelligere etc., determinat de colore halo. Et dicit quod in nube clara et subtili, quae incipit converti in aquam et dicitur nubes rorida, in qua apparet halo, sunt quaedam parvae guttulae indivisibiles secundum sensum, quae sunt parva specula, in quibus apparet tantum color corporis obiecti, non figura: ex quo in illis simul sumptis apparet color, mixtus ex lumine stellae et colore nubis a qua fit refractio. Et hoc ideo, quia nubes non est speculum purum: nam si esset speculum purum, non admixtum alteri colori, pure representaret colorem obiecti. Et quia color albus est propinquior lumini ipsius stellae, ideo in illa parte halo quae plus obtinet de lumine, scilicet in medio, apparet color albus; sed in parte remotiori, scilicet in circumferentia, apparet maior nigredo, tum propter minus lumen ibi existens, tum etiam propter maiorem albedinem alterius partis: quia opposita iuxta se posita maiora videntur. Est autem maius lumen in medio, quia radii luminosi super illam partem cadunt perpendiculariter versus terram, quo quidem modo habent causare maius lumen.

Deinde cum dicit: saepius autem fit etc., ostendit causam unius accidentis circa halo, scilicet quare halo saepius apparet circa lunam quam circa solem. Et huius ratio est, quia sol propter maiorem caliditatem citius disgregat humorem consistentem in nube, quam luna quae habet minorem virtutem calefaciendi. Sed circa alia astra apparet eadem halo propter easdem causas, vel propter causas proportionales dictis; sed tamen non eodem modo significat: quia circa lunam vel solem est signum pluviae, vel venti, aut serenitatis, sed circa alia astra est signum tenuis et debilis caliginis, non habentis fecunditatem. Considerandum est autem quod halo fit etiam circa lucernas de nocte tempore hiemali, et tunc lumen lucernae habet rationem obiecti refracti, aer circumstans humidus et ingrossatus a frigore est quasi speculum, oculus vero est id ad quod fit refractio. Apparet etiam tempore magni caloris circa oculum et circa lumina, propter humiditatem existentem in oculo, maxime quando homo surgit a somno et fricat oculos: tunc enim evaporare facit humorem existentem in oculo extrinsecus. Apparet autem et videtur esse prope circa lumen: quia propter parvam distantiam lumen alterat totum medium usque ad oculum, et ideo visus totum continuum iudicat unum cum lumine. Quare autem appareat circularis figurae, cum tamen flamma sit figurae ovalis et oblongae, ad perspectivam communem pertinet.

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Lectio 5

4	4
ἡ δ' ἶρις ὅτι μέν ἐστιν ἀνάκλασις, εἴρηται πρότερον ποία δέ τις ἀνάκλασις, καὶ πῶς καὶ διὰ τίν' αἰτίαν ἕκαστα γίγνεται τῶν συμβαινόντων περὶ ταύτην, λέγωμεν νῦν. ἀνακλωμένη μὲν οὖν ἡ ὄψις ἀπὸ πάντων φαίνεται τῶν λείων, (373b.) τούτων δ' ἐστὶν καὶ ἀὴρ καὶ ὕδωρ. γίγνεται δὲ ἀπὸ μὲν ἀέρος, ὅταν τύχῃ συνιστάμενος. διὰ δὲ τὴν τῆς ὄψεως ἀσθένειαν πολλάκις καὶ ἄνευ συστάσεως ποιεῖ ἀνάκλασιν, οἷόν ποτε συνέβαινέ τινι πάθος ἠρέμα καὶ οὐκ ὀξὺ βλέποντι ἀεὶ γὰρ εἴδωλον ἐδόκει προηγεῖσθαι βαδίζοντι αὐτῷ, ἐξ ἐναντίας βλέπον πρὸς αὐτόν. τοῦτο δ' ἔπασχε διὰ τὸ τὴν ὄψιν ἀνακλᾶσθαι πρὸς αὐτόν οὕτω γὰρ ἀσθενὴς ἦν καὶ λεπτὴ πάμπαν ὑπὸ τῆς ἀρρωστίας, ὥστ' ἔνοπτρον ἐγίγνετο καὶ ὁ πλησίον ἀήρ, καὶ οὐκ ἐδύνατο ἀπωθεῖν—ὡς ὁ πόρρω καὶ πυκνός διόπερ αἵ τ' ἄκραι ἀνεσπασμέναι φαίνονται ἐν τῇ θαλάττῃ, καὶ μείζω τὰ μεγέθη πάντων, ὅταν εὖροι πνέωσι, καὶ τὰ ἐν ταῖς ἀχλύσιν, οἷον καὶ ἥλιος καὶ ἄστρα ἀνίσχοντα καὶ δύνοντα μᾶλλον ἢ μεσουρανοῦντα. ἀπὸ δὲ ὕδατος μάλιστα ἀνακλᾶται, καὶ ἀπὸ ἀρχομένου γίγνεσθαι μᾶλλον ἔτι ἢ ἀπ' ἀέρος ἕκαστον γὰρ τῶν μορίων ἐξ ὧν γίγνεται συνισταμένων ἡ ψακὰς ἔνοπτρον ἀναγκαῖον εἶναι μᾶλλον τῆς ἀχλύος. ἐπεὶ δὲ καὶ δῆλον καὶ εἴρηται πρότερον ὅτι ἐν τοῖς τοιούτοις ἐνόπτροις τὸ χρῶμα μόνον ἐμφαίνεται, τὸ δὲ σχῆμα ἄδηλον, ἀναγκαῖον, ὅταν ἄρχηται ὕειν καὶ ἤδη μὲν συνιστῆται εἰς ψακάδας ὁ ἐν τοῖς νέφεσιν ἀήρ, μήπω δὲ ὕῃ, ἐὰν ἐξ ἐναντίας ᾖ ὁ ἥλιος ἢ ἄλλο τι οὕτω λαμπρὸν ὥστε γίγνεσθαι ἔνοπτρον τὸ νέφος, καὶ τὴν ἀνάκλασιν γίγνεσθαι πρὸς τὸ λαμπρὸν ἐξ ἐναντίας, γίγνεσθαι ἔμφασιν χρώματος, οὐ σχήματος. ἑκάστου δ' ὄντος τῶν ἐνόπτρων μικροῦ καὶ ἀοράτου, τῆς δ' ἐξ ἁπάντων αὐτῶν συνεχείας τοῦ μεγέθους ὁρωμένης, ἀνάγκη συνεχὲς μέγεθος τοῦ αὐτοῦ φαίνεσθαι χρώματος ἕκαστον γὰρ τῶν ἐνόπτρων τὸ αὐτὸ ἀποδίδωσι χρῶμα τῷ συνεχεῖ. ὥστ' ἐπεὶ ταῦτ' ἐνδέχεται συμβαίνειν, ὅταν τοῦτον ἔχῃ τὸν τρόπον ὅ τε ἥλιος καὶ τὸ νέφος καὶ ἡμεῖς ὦμεν μεταξὺ αὐτῶν, ἔσται διὰ τὴν ἀνάκλασιν ἔμφασίς τις. ἀλλὰ μὴν καὶ φαίνεται τότε καὶ οὐκ ἄλλως ἐχόντων γιγνομένη ἡ ἶρις.	We have already stated that the rainbow is a reflection: we have now to explain what sort of reflection it is, to describe its various concomitants, and to assign their causes. Sight is reflected from all smooth surfaces, such as are air and water among others. Air must be condensed if it is to act as a mirror, though it often gives a reflection even uncondensed when the sight is weak. Such was the case of a man whose sight was faint and indistinct. He always saw an image in front of him and facing him as he walked. This was because his sight was reflected back to him. Its morbid condition made it so weak and delicate that the air close by acted as a mirror, just as distant and condensed air normally does, and his sight could not push it back. So promontories in the sea 'loom' when there is a south-east wind, and everything seems bigger, and in a mist, too, things seem bigger: so, too, the sun and the stars seem bigger when rising and setting than on the meridian. But things are best reflected from water, and even in process of formation it is a better mirror than air, for each of the particles, the union of which constitutes a raindrop, is necessarily a better mirror than mist. Now it is obvious and has already been stated that a mirror of this kind renders the colour of an object only, but not its shape. Hence it follows that when it is on the point of raining and the air in the clouds is in process of forming into raindrops but the rain is not yet actually there, if the sun is opposite, or any other object bright enough to make the cloud a mirror and cause the sight to be reflected to the object then the reflection must render the colour of the object without its shape. Since each of the mirrors is so small as to be invisible and what we see is the continuous magnitude made up of them all, the reflection necessarily gives us a continuous magnitude made up of one colour; each of the mirrors contributing the same colour to the whole. We may deduce that since these conditions are realizable there will be an appearance due to reflection whenever the sun and the cloud are related in the way described and we are between them. But these are just the conditions under which the rainbow appears.
ὅτι μὲν οὖν ἀνάκλασις ἡ ἶρις τῆς ὄψεως πρὸς τὸν ἥλιόν ἐστι, φανερόν διὸ καὶ ἐξ ἐναντίας ἀεὶ γίγνεται, ἡ δ' ἅλως περὶ αὐτόν καίτοι ἄμφω ἀνάκλασις ἀλλ' ἥ γε τῶν χρωμάτων (374a.) ποικιλία διαφέρει ἡ μὲν γὰρ ἀφ' ὕδατος καὶ μέλανος γίγνεται ἀνάκλασις καὶ πόρρωθεν, ἡ δ' ἐγγύθεν καὶ ἀπὸ ἀέρος λευκοτέρου τὴν φύσιν. φαίνεται δὲ τὸ λαμπρὸν διὰ τοῦ μέλανος ἢ ἐν τῷ μέλανι (διαφέρει γὰρ οὐδέν) φοινικοῦν (ὁρᾶν δ' ἔξεστι τό γε τῶν χλωρῶν ξύλων πῦρ, ὡς ἐρυθρὰν ἔχει τὴν φλόγα διὰ τὸ τῷ καπνῷ πολλῷ μεμεῖχθαι τὸ πῦρ λαμπρὸν ὂν καὶ λευκόν) καὶ δι' ἀχλύος καὶ καπνοῦ ὁ ἥλιος φαίνεται φοινικοῦς. διὸ ἡ μὲν τῆς ἴριδος ἀνάκλασις ἡ μὲν πρώτη τοιαύτην ἔχειν φαίνεται τὴν χρόαν (ἀπὸ ῥανίδων γὰρ μικρῶν γίγνεται ἡ ἀνάκλασις), ἡ δὲ τῆς ἅλω οὔ. περὶ δὲ τῶν ἄλλων χρωμάτων ὕστερον ἐροῦμεν. ἔτι δὲ περὶ αὐτὸν μὲν τὸν ἥλιον οὐ γίγνεται διατριβὴ τοιαύτης συστάσεως, ἀλλ' ἢ ὕει ἢ διαλύεται. ἐκ δὲ τῶν ἐναντίων ἐν τῷ μεταξὺ τῆς τοῦ ὕδατος γενέσεως γίγνεταί τις χρόνος τούτου γὰρ μὴ συμβαίνοντος ἦσαν ἂν κεχρωματισμέναι αἱ ἅλως ὥσπερ ἡ ἶρις. νῦν δ' ὅλα μὲν οὐ γίγνεται τοιαύτην ἔχοντα τὴν ἔμφασιν, οὐδὲ κύκλῳ, μικρὰ δὲ καὶ κατὰ μόριον, αἳ καλοῦνται ῥάβδοι, ἐπεὶ εἰ συνίστατο τοιαύτη ἀχλὺς οἵα γένοιτ' ἂν ὕδατος ἤ τινος ἄλλου μέλανος, καθάπερ λέγομεν, ἐφαίνετο ἂν ἡ ἶρις ὅλη, ὥσπερ ἡ περὶ τοὺς λύχνους. περὶ γὰρ τούτους τὰ πλεῖστα νοτίων ὄντων ἶρις γίγνεται τοῦ χειμῶνος, μάλιστα δὲ δήλη γίγνεται τοῖς ὑγροὺς ἔχουσι τοὺς ὀφθαλμούς τούτων γὰρ ἡ ὄψις ταχὺ δι' ἀσθένειαν ἀνακλᾶται. γίγνεται δ' ἀπό τε τῆς τοῦ ἀέρος ὑγρότητος καὶ ἀπὸ λιγνύος τῆς ἀπὸ τῆς φλογὸς ἀπορρεούσης καὶ μειγνυμένης τότε γὰρ γίγνεται ἔνοπτρον, καὶ διὰ τὴν μελανίαν καπνώδης γὰρ ἡ λιγνύς τὸ δὲ τοῦ λύχνου φῶς οὐ λευκὸν ἀλλὰ πορφυροῦν φαίνεται κύκλῳ καὶ ἰριῶδες, φοινικοῦν δ' οὔ ἔστι γὰρ ἥ τε ὄψις ὀλίγη ἡ ἀνακλωμένη, καὶ μέλαν τὸ ἔνοπτρον. ἡ δ' ἀπὸ τῶν κωπῶν τῶν ἀναφερομένων ἐκ τῆς θαλάττης ἶρις τῇ μὲν θέσει τὸν αὐτὸν γίγνεται τρόπον τῇ ἐν τῷ οὐρανῷ, τὸ δὲ χρῶμα ὁμοιοτέρα τῇ περὶ τοὺς λύχνους οὐ γὰρ φοινικῆν ἀλλὰ πορφυρᾶν ἔχουσα φαίνεται τὴν χρόαν. ἡ δ' ἀνάκλασις ἀπὸ τῶν μικροτάτων μὲν συνεχῶν δὲ γίγνεται ῥανίδων αὗται δ' ὕδωρ ἀποκεκριμένον εἰσὶν ἤδη παντελῶς. γίγνεται δὲ κἄν (374b.) τις λεπταῖς ῥαίνῃ ῥανίσιν εἴς τι τοιοῦτον χωρίον ὃ τὴν θέσιν πρὸς τὸν ἥλιον ἐστραμμένον ἐστὶ καὶ τῇ μὲν ὁ ἥλιος ἀνέχῃ τῇ δὲ σκιάζῃ ἐν τῷ τοιούτῳ γάρ, ἐὰν εἴσω τις ῥαίνῃ, τῷ ἑστῶτι ἐκτός, ᾗ ἐπαλλάττουσιν αἱ ἀκτῖνες καὶ ποιοῦσι τὴν σκιάν, φαίνεται ἶρις. ὁ δὲ τρόπος καὶ ἡ χρόα ὁμοία καὶ τὸ αἴτιον τὸ αὐτὸ τῇ ἀπὸ τῶν κωπῶν τῇ γὰρ χειρὶ κώπῃ χρῆται ὁ ῥαίνων.	So it is clear that the rainbow is a reflection of sight to the sun. So the rainbow always appears opposite the sun whereas the halo is round it. They are both reflections, but the rainbow is distinguished by the variety of its colours. The reflection in the one case is from water which is dark and from a distance; in the other from air which is nearer and lighter in colour. White light through a dark medium or on a dark surface (it makes no difference) looks red. We know how red the flame of green wood is: this is because so much smoke is mixed with the bright white firelight: so, too, the sun appears red through smoke and mist. That is why in the rainbow reflection the outer circumference is red (the reflection being from small particles of water), but not in the case of the halo. The other colours shall be explained later. Again, a condensation of this kind cannot persist in the neighbourhood of the sun: it must either turn to rain or be dissolved, but opposite to the sun there is an interval during which the water is formed. If there were not this distinction haloes would be coloured like the rainbow. Actually no complete or circular halo presents this colour, only small and fragmentary appearances called 'rods'. But if a haze due to water or any other dark substance formed there we should have had, as we maintain, a complete rainbow like that which we do find lamps. A rainbow appears round these in winter, generally with southerly winds. Persons whose eyes are moist see it most clearly because their sight is weak and easily reflected. It is due to the moistness of the air and the soot which the flame gives off and which mixes with the air and makes it a mirror, and to the blackness which that mirror derives from the smoky nature of the soot. The light of the lamp appears as a circle which is not white but purple. It shows the colours of the rainbow; but because the sight that is reflected is too weak and the mirror too dark, red is absent. The rainbow that is seen when oars are raised out of the sea involves the same relative positions as that in the sky, but its colour is more like that round the lamps, being purple rather than red. The reflection is from very small particles continuous with one another, and in this case the particles are fully formed water. We get a rainbow, too, if a man sprinkles fine drops in a room turned to the sun so that the sun is shining in part of the room and throwing a shadow in the rest. Then if one man sprinkles in the room, another, standing outside, sees a rainbow where the sun's rays cease and make the shadow. Its nature and colour is like that from the oars and its cause is the same, for the sprinkling hand corresponds to the oar.

Postquam philosophus determinavit de halo in speciali, determinat nunc de iride etiam in speciali. Et circa hoc duo facit: primo praemittit intentionem suam, et dicit quod dictum est prius, quod iris est quaedam refractio, scilicet causaliter, ut dictum est; sed qualis sit refractio, et propter quam causam, et quomodo fiant singula accidentia circa iridem, dicimus nunc.

Secundo ibi: refractus quidem igitur etc., prosequitur intentionem suam. Et circa hoc tria facit: primo ostendit causam et modum generationis colorum in iride; secundo determinat de ea quantum ad figuram et consequentia figuram eius, ibi: quoniam autem neque circulum etc.; tertio determinat de tempore et modo apparitionis eius, ibi: quod autem in minoribus et cetera. Prima iterum dividitur in duas partes: in prima determinat de generatione colorum principalium; in secunda de generatione colorum minus principalium, ibi: xanthos autem et cetera. Circa primum tria facit: primo determinat de generatione colorum iridis in generali; secundo de generatione primi coloris in speciali, ibi: quod quidem igitur iris etc.; tertio de generatione aliorum colorum, ibi: quoniam autem color et cetera. Circa primum iterum duo facit: primo ponit quandam suppositionem necessariam ad propositum; secundo concludit modum generationis colorum iridis, ibi: quoniam autem et manifestum et cetera. Dicit ergo primo quod radius visualis natus est refrangi ab omni corpore plano et terminato, sicut sunt aer et aqua. Quod autem refrangatur ab aere probat quatuor signis. Primum est quia Antipheronti propter debilitatem sui visus accidit, quod semper videbat similitudinem suae faciei in aere ipso aspiciendo, propter refractionem suae faciei in aere: signum est igitur quod refractio fiat in aere. Intelligendum est autem circa istud primum signum, quod Aristoteles hic loquitur secundum opinionem antiquorum mathematicorum, ut dictum est supra, sed secundum veritatem illa est causa passionis accidentis circa Antipherontem, quod circa pupillam eius erat humor innaturalis grossus, alterans visum, et ipse propter infirmitatem iudicabat de isto humore et de idolo in eo impresso, sicut de quodam extrinseco: quia utebatur pupilla quasi speculo, et humore quasi obiecto, et iudicabat ipsum esse hominem ambulantem, propter similitudinem passionis apparentis in colore et lineatione. Sicut aliis laborantibus infirmitate oculorum apparet tela aranearum ante oculos, quibusdam autem muscae volantes etc., cum tamen sit humor in pupilla respersus. Secundum signum est, quia summitates navium, scilicet summitas arboris navis, et etiam montes alti in mare, videntur breviores et grossiores: quia aer supra mare existens magis accedit ad dispositionem opaci, quia est ingrossatus ab humiditate et frigiditate maris, ex quo potest esse speculum, quod non posset esse nisi aer esset aliquo modo inspissatus et ingrossatus. Tertium signum quod refractio fiat ab aere ita consistente et inspissato, est quia cum flant Euri, qui sunt venti Orientales humidi, omnia videntur maiora propter refractionem ad aerem ingrossatum a flatu Euri. Quartum signum est, quia tempore caliginis, scilicet in mane quando sol adhuc non rarefecit aerem, et in sero et aliis temporibus nebulosis, sol et alia astra orientia vel occidentia videntur maiora quam in medio caeli, propter talem refractionem ad aerem istum caliginosum et grossum. Quod autem ab aqua fiat refractio manifestat, quia si sit ab aere, multo magis fiet ab aqua, quae est planae superficiei et est magis densa quam aer, et ex consequenti magis potest esse speculum quam aer vel caligo. Et adhuc magis fit a caligine incipiente converti in aquam quam a simplici aere, quia etiam talis caligo magis accedit ad rationem speculi quam aer.

Deinde cum dicit: quoniam autem et manifestum etc., concludit modum generationis colorum iridis in generali. Et dicit quod, sicut dictum est prius, si fuerit nubes rorida, idest habens parvas guttulas semilucidas ad modum roris, sicut accidit cum incipit pluere antequam pluat, vel etiam cum desinit, et talis nubes posita fuerit ex opposito solis vel alterius astri fulgidi, ita ut fiat speculum refrangens visum ad oppositum, scilicet ad astrum, tunc fiunt colores iridis in tali speculo. Sed quia illae parvae guttulae nubis sunt specula parva, et indivisibilia secundum sensum, ideo in illis apparet color tantum, non autem figura obiecti. Quia autem sunt continuatae adinvicem, ideo in illis apparet color continuus, non interruptus. Sed ista reverberatio colorum solum contingit, quando nubes et astrum ponuntur ex opposito, et visus noster est in medio ipsorum.

Deinde cum dicit: quod quidem igitur iris etc., ponit in speciali modum generationis coloris punicei, qui est primus inter principales colores iridis. Et circa hoc tria facit: primo praemittit quasdam suppositiones necessarias ad propositum; secundo ostendit causam coloris punicei, ibi: propter quod iridis etc.; tertio ponit modum generationis talis coloris, declarando ipsum per quaedam signa, ibi: apparet utique iris et cetera. Ponit ergo primo tres suppositiones. Quarum prima est quod iris est refractio, idest apparitio ex refractione causata, et quia causatur ex refractione a nube opposita, ideo semper fit ex opposito ad astrum: halo autem fit circa ipsum; conveniunt tamen in hoc quod utrumque fit ex quadam refractione. Secundum quod supponit, est quaedam differentia inter halo et iridem: quia in halo non est illa varietas colorum quae est in iride; iterum in iride est refractio a longe et a nigro, sed halo fit de prope et ab aere albiori secundum naturam. Tertia suppositio est, quod fulgidum seu lucidum, visum in nigro vel per nigrum, apparet puniceum. In signum cuius ignis lignorum viridium habet flammam rubeam, quia magna multitudo fumi, qui est niger, miscetur tali igni lucido. Sol etiam, visus per caliginem vel fumum, apparet puniceus, idest subrubeus, tendens ad albedinem. Sciendum est autem, quod quando aer vel aliud perspicuum est in propria natura purum, et non aliquo colore coloratum, tunc habet solum rationem medii per quod videtur obiectum, non autem habet rationem obiecti. Quando autem est impurum et coloratum aliquo colore, tunc habet rationem medii et obiecti, et ex colore utriusque, scilicet medii et obiecti, componitur unum obiectum completum visus. Ex hoc, quando lucidum vel obiectum transit per fumum vel caliginem vel aliud nigrum, tunc ex utroque componitur tertius color qui dicitur puniceus: et hic tanto magis accedit ad album, quanto magis in tali mixtione dominatur lucidum; et ita similiter de nigro. Et huius signum evidens potest esse, quod radius solaris transiens per amphoram vini nigri, videtur puniceus, secundum modum praedictum.

Deinde cum dicit: propter quod iridis etc., ponit causam coloris punicei in iride, dicens quod prima refractio, idest primus color ex refractione causatus, apparet propter refractionem luminis solis a guttis parvis, quae sunt in nube nigra et aquosa: quia fulgidum visum in nigro apparet puniceum. Sic autem non est de halo. Non est autem tanta diversitas colorum in halo sicut in iride: quia nubes in qua videtur halo, non est tantae permanentiae circa solem sicut nubes in qua apparet iris: quia nubes circa solem vel convertitur in pluviam, vel cito dissolvitur propter calorem solis, sed nubes existens in opposito solis facit aliquam moram, saltem per totum tempus in quo generatur aqua ex nube: quod si esset in nube in qua generatur halo, tunc utique halo appareret colorata sicut iris. Et eadem etiam causa, quia iris fit ex opposito, non fit sub figura circuli completi, sed est figura eius parva: quia non est maior semicirculo, divisa per quasdam virgas, quae apparent in medio praedictorum colorum. Et si talis caligo aliter poneretur circa solem, esset maioris figurae iris.

Deinde cum dicit: apparet utique iris etc., declarat modum generationis coloris punicei per quaedam signa. Et primum, per quod demonstratur quod iris fiat per refractionem ad aerem grossum et caliginosum, est quia in hieme circa lucernas de nocte apparet circulus habens colorem puniceum iridis, quod fit propter refractionem luminis lucernae ad aerem circumstantem, qui est ingrossatus a frigido, vel etiam est terminatus per admixtionem fumi egredientis a lucerna, et ita est nigrefactus a fumo. Hoc autem fit maxime flantibus ventis Australibus, quia tunc aer est magis ingrossatus propter humorem quem secum adducunt venti Australes. Et hoc maxime accidit his qui habent oculos debilitatos propter nimiam humiditatem: tum quia aer etiam tunc magis ingrossatur propter humorem evaporantem ab oculis; tum quia visus facile refrangitur ab aere grosso propter debilitatem, supposito secundum antiquos, quod visus sit qui refrangatur, sicut supra dictum est. Sed tamen possumus dicere quod huius ratio est, quia visus debilis non potest operari circa obiectum forte, cuiusmodi est lumen, propter debilitatem: sicut accidit noctuae, quae propter debilitatem visus non potest aspicere lumen solis. Et ideo propter infirmitatem, quae quasi velat oculum, intuetur lumen lucernae sub quadam caligine, et videtur ei lumen etiam magis obscurum quam sit. Assignat autem duas rationes, quare lumen lucernae non facit colorem puniceum in sua iride, sicut lumen solis. Prima est, quia visus debiliter alteratur a lumine lucernae debili existente, et ideo lumen non apparet ita album, sicut appareret in alteratione forti. Secunda autem est, quia speculum in quo lumen videtur, scilicet aer circumstans, est nigrum propter fumum lucernae, et propter hoc ostendit colorem solis non puniceum, sed purpureum, qui magis accedit ad nigrum quam puniceus. Secundum signum est, quia in aqua maris sursum elevata a remis nautarum, apparent tales colores, propter refractionem luminis ad aerem ingrossatum propter frigiditatem et humiditatem aquae maris, et terminatum etiam et aliquo modo denigratum ab umbra quam faciunt latera navis; et propter hoc tales colores sunt similiores coloribus iridis lucernae quam iridis caelestis, quia talis iris non habet colorem puniceum, sed purpureum. Refractio autem in tali iride fit a guttis parvis et continuis, quae elevantur a remis. Tertium signum est, quia quando aliquis est in aliquo loco, qui ex una parte est tenebrosus et ex alia, scilicet ex opposita parte, irradiatur a sole, et rorat, idest distillat, humorem aqueum, sive manu sive ore sive alio instrumento, subtili stillatione, tunc apparent similes colores iridis, propter refractionem luminis ad talem aquam stillantem et nigram apparentem propter umbram. Hoc autem manifeste videtur in hominibus velociter loquentibus: ab ore enim eorum dum loquuntur, saepe egreditur quidam humor aqueus, rotundus et inflatus, in quo apparent colores iridis, si homo fuerit versus solem. Pueri etiam quibusdam instrumentis vitreis ori suo appositis, emittunt tales inflationes rotundas ad modum vesicarum, in quibus apparent colores iridis. Hoc etiam apparet in aqua dum percutitur, et in sapone quando lotrices ipsum manibus liquefaciunt, et in multis aliis, a quibus elevantur huiusmodi inflationes rotundae, et in eis apparent colores iridis. Signum est ergo quod iris caelestis generetur per refractionem luminis a nube rorida, quia etiam praedicta iris causatur per refractionem ab aqua rorida.

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Lectio 6

ὅτι δὲ τὸ χρῶμα τοιοῦτον, ἅμα δῆλον ἔσται καὶ περὶ τῶν ἄλλων χρωμάτων τῆς φαντασίας, ἐκ τῶνδε. δεῖ γὰρ νοήσαντας, ὥσπερ εἴρηται, καὶ ὑποθεμένους πρῶτον μὲν ὅτι τὸ λαμπρὸν ἐν τῷ μέλανι ἢ διὰ τοῦ μέλανος χρῶμα ποιεῖ φοινικοῦν, δεύτερον δ' ὅτι ἡ ὄψις ἐκτεινομένη ἀσθενεστέρα γίγνεται καὶ ἐλάττων, τρίτον δ' ὅτι τὸ μέλαν οἷον ἀπόφασίς ἐστιν τῷ γὰρ ἐκλείπειν τὴν ὄψιν φαίνεται μέλαν διὸ τὰ πόρρω πάντα μελάντερα φαίνεται, διὰ τὸ μὴ διικνεῖσθαι τὴν ὄψιν. θεωρείσθω μὲν οὖν ταῦτ' ἐκ τῶν περὶ τὰς αἰσθήσεις συμβαινόντων ἐκείνων γὰρ ἴδιοι οἱ περὶ τούτων λόγοι νῦν δ' ὅσον ἀνάγκη, τοσοῦτον περὶ αὐτῶν λέγωμεν. φαίνεται δ' οὖν διὰ ταύτην τὴν αἰτίαν τά τε πόρρω μελάντερα καὶ ἐλάττω καὶ λειότερα, καὶ τὰ ἐν τοῖς ἐνόπτροις, καὶ τὰ νέφη μελάντερα βλέπουσιν εἰς τὸ ὕδωρ ἢ εἰς αὐτὰ τὰ νέφη. καὶ τοῦτο πάνυ ἐπιδήλως διὰ γὰρ τὴν ἀνάκλασιν ὀλίγῃ τῇ ὄψει θεωροῦνται. διαφέρει δ' οὐδὲν τὸ ὁρώμενον μεταβάλλειν ἢ τὴν ὄψιν ἀμφοτέρως γὰρ ἔσται ταὐτόν. πρὸς δὲ τούτοις δεῖ μὴ λεληθέναι καὶ τόδε συμβαίνει γὰρ ὅταν ᾖ τοῦ ἡλίου νέφος πλησίον, εἰς μὲν αὐτὸ βλέποντι μηδὲν φαίνεσθαι κεχρωματισμένον ἀλλ' εἶναι λευκόν, ἐν δὲ τῷ ὕδατι αὐτὸ τοῦτο θεωροῦντι χρῶμά τι ἔχειν τῆς ἴριδος. δῆλον τοίνυν ὅτι ἡ ὄψις ὥσπερ καὶ τὸ μέλαν κλωμένη δι' ἀσθένειαν μελάντερον ποιεῖ φαίνεσθαι, καὶ τὸ λευκὸν ἧττον λευκόν, καὶ προσάγει πρὸς τὸ μέλαν. ἡ μὲν οὖν ἰσχυροτέρα ὄψις εἰς φοινικοῦν χρῶμα μετέβαλεν, ἡ δ' ἐχομένη εἰς τὸ πράσινον, ἡ δὲ ἔτι ἀσθενεστέρα εἰς τὸ ἁλουργόν. ἐπὶ δὲ τὸ πλέον οὐκέτι φαίνεται, ἀλλ' ἐν τοῖς τρισίν, ὥσπερ καὶ τῶν ἄλλων τὰ πλεῖστα, καὶ τούτων ἔσχεν τέλος τῶν δ' ἄλλων ἀναίσθητος ἡ μεταβολή.	That the colours of the rainbow are those we described and how the other colours come to appear in it will be clear from the following considerations. We must recognize, as we have said, and lay down: first, that white colour on a black surface or seen through a black medium gives red; second, that sight when strained to a distance becomes weaker and less; third, that black is in a sort the negation of sight: an object is black because sight fails; so everything at a distance looks blacker, because sight does not reach it. The theory of these matters belongs to the account of the senses, which are the proper subjects of such an inquiry; we need only state about them what is necessary for us. At all events, that is the reason why distant objects and objects seen in a mirror look darker and smaller and smoother, why the reflection of clouds in water is darker than the clouds themselves. This latter is clearly the case: the reflection diminishes the sight that reaches them. It makes no difference whether the change is in the object seen or. in the sight, the result being in either case the same. The following fact further is worth noticing. When there is a cloud near the sun and we look at it does not look coloured at all but white, but when we look at the same cloud in water it shows a trace of rainbow colouring. Clearly, then, when sight is reflected it is weakened and, as it makes dark look darker, so it makes white look less white, changing it and bringing it nearer to black. When the sight is relatively strong the change is to red; the next stage is green, and a further degree of weakness gives violet. No further change is visible, but three completes the series of colours (as we find three does in most other things), and the change into the rest is imperceptible to sense.
διὸ καὶ ἡ (375a.) ἶρις τρίχρως φαίνεται, ἑκατέρα μέν, ἐναντίως δέ. ἡ μὲν οὖν πρώτη τὴν ἔξω φοινικῆν ἔχει ἀπὸ μεγίστης γὰρ περιφερείας πλείστη προσπίπτει ὄψις πρὸς τὸν ἥλιον, μεγίστη δ' ἡ ἔξω ἡ δ' ἐχομένη καὶ ἡ τρίτη ἀνάλογον. ὥστ' εἰ τὰ περὶ τῶν χρωμάτων τῆς φαντασίας εἴρηται καλῶς, ἀνάγκη τρίχρων τε εἶναι αὐτὴν καὶ τούτοις τοῖς χρώμασι κεχρῶσθαι μόνοις. τὸ δὲ ξανθὸν φαίνεται διὰ τὸ παρ' ἄλληλα φαίνεσθαι. τὸ γὰρ φοινικοῦν παρὰ τὸ πράσινον λευκὸν φαίνεται. σημεῖον δὲ τούτου ἐν γὰρ τῷ μελαντάτῳ νέφει μάλιστα ἄκρατος γίγνεται ἶρις συμβαίνει δὲ τότε ξανθότερον εἶναι δοκεῖν τὸ φοινικοῦν. ἔστι δὲ τὸ ξανθὸν ἐν τῇ ἴριδι χρῶμα μεταξὺ τοῦ τε φοινικοῦ καὶ πρασίνου χρώματος. διὰ τὴν μελανίαν οὖν τοῦ κύκλῳ νέφους ὅλον αὐτοῦ φαίνεται τὸ φοινικοῦν λευκόν ἔστι γὰρ πρὸς ἐκεῖνα λευκόν. καὶ πάλιν ἀπομαραινομένης τῆς ἴριδος ἐγγύτατα, ὅταν λύηται τὸ φοινικοῦν ἡ γὰρ νεφέλη λευκὴ οὖσα, προσπίπτουσα παρὰ τὸ πράσινον, μεταβάλλει εἰς τὸ ξανθόν. μέγιστον δὲ σημεῖον τούτων ἡ ἀπὸ τῆς σελήνης ἶρις φαίνεται γὰρ λευκὴ πάμπαν. γίγνεται δὲ τοῦτο ὅτι ἔν τε τῷ νέφει ζοφερῷ φαίνεται καὶ ἐν νυκτί. ὥσπερ οὖν πῦρ ἐπὶ πῦρ, μέλαν παρὰ μέλαν ποιεῖ τὸ ἠρέμα λευκὸν παντελῶς φαίνεσθαι λευκόν τοῦτο δ' ἐστὶν τὸ φοινικοῦν. γίγνεται δὲ τοῦτο τὸ πάθος καταφανὲς καὶ ἐπὶ τῶν ἀνθῶν ἐν γὰρ τοῖς ὑφάσμασιν καὶ ποικίλμασιν ἀμύθητον διαφέρει τῇ φαντασίᾳ ἄλλα παρ' ἄλλα τιθέμενα τῶν χρωμάτων, οἷον καὶ τὰ πορφυρᾶ ἐν λευκοῖς ἢ μέλασιν ἐρίοις, ἔτι δ' ἐν αὐγῇ τοιᾳδὶ ἢ τοιᾳδί διὸ καὶ οἱ ποικιλταί φασι διαμαρτάνειν ἐργαζόμενοι πρὸς τὸν λύχνον πολλάκις τῶν ἀνθῶν, λαμβάνοντες ἕτερα ἀνθ' ἑτέρων.	Hence also the rainbow appears with three colours; this is true of each of the two, but in a contrary way. The outer band of the primary rainbow is red: for the largest band reflects most sight to the sun, and the outer band is largest. The middle band and the third go on the same principle. So if the principles we laid down about the appearance of colours are true the rainbow necessarily has three colours, and these three and no others. The appearance of yellow is due to contrast, for the red is whitened by its juxtaposition with green. We can see this from the fact that the rainbow is purest when the cloud is blackest; and then the red shows most yellow. (Yellow in the rainbow comes between red and green.) So the whole of the red shows white by contrast with the blackness of the cloud around: for it is white compared to the cloud and the green. Again, when the rainbow is fading away and the red is dissolving, the white cloud is brought into contact with the green and becomes yellow. But the moon rainbow affords the best instance of this colour contrast. It looks quite white: this is because it appears on the dark cloud and at night. So, just as fire is intensified by added fire, black beside black makes that which is in some degree white look quite white. Bright dyes too show the effect of contrast. In woven and embroidered stuffs the appearance of colours is profoundly affected by their juxtaposition with one another (purple, for instance, appears different on white and on black wool), and also by differences of illumination. Thus embroiderers say that they often make mistakes in their colours when they work by lamplight, and use the wrong ones.
διότι μὲν οὖν τρίχρως τε, καὶ ὅτι ἐκ τούτων φαίνεται τῶν χρωμάτων μόνων ἡ ἶρις, εἴρηται. διπλῆ δὲ καὶ ἀμαυροτέρα τοῖς χρώμασιν ἡ περιέχουσα, καὶ τῇ θέσει τὰς χρόας ἐξ ἐναντίας ἔχει κειμένας διὰ τὴν αὐτὴν αἰτίαν μακροτέρα γὰρ ἀποτεινομένη ἡ ὄψις ὥσπερ τὸ πορρώτερον ὁρᾷ, καὶ τὸ ἐνταῦθα τὸν αὐτὸν τρόπον. ἀσθενεστέρα οὖν ἀπὸ τῆς ἔξωθεν ἡ (375b.) ἀνάκλασις γίγνεται διὰ τὸ πορρώτερον ποιεῖσθαι τὴν ἀνάκλασιν, ὥστ' ἐλάττων προσπίπτουσα τὰ χρώματα ποιεῖ ἀμαυρότερα φαίνεσθαι. καὶ ἀντεστραμμένως δὴ διὰ τὸ πλείω ἀπὸ τῆς ἐλάττονος καὶ τῆς ἐντὸς περιφερείας προσπίπτειν πρὸς τὸν ἥλιον ἐγγυτέρω γὰρ τῆς ὄψεως οὖσα ἀνακλᾶται ἀπὸ τῆς ἐγγυτάτω περιφερείας τῆς πρώτης ἴριδος. ἐγγυτάτω δὲ ἐν τῇ ἔξωθεν ἴριδι ἡ ἐλαχίστη περιφέρεια, ὥστε αὕτη ἕξει τὸ χρῶμα φοινικοῦν ἡ δ' ἐχομένη καὶ ἡ τρίτη κατὰ λόγον. ἡ ἔξω ἶρις ἐφ' ᾧ τὸ Β ἡ ἔσω, ἡ πρώτη, ἐφ' ᾧ τὸ Α τὰ χρώματα δ', ἐφ' ᾧ τὸ Γ, φοινικοῦν, ἐφ' ᾧ τὸ Δ, πράσινον, ἐφ' ᾧ Ε, ἁλουργόν τὸ ξανθὸν δὲ φαίνεται ἐφ' οὗ τὸ Ζ. τρεῖς δ' οὐκέτι γίγνονται, οὐδὲ πλείους ἴριδες, διὰ τὸ καὶ τὴν δευτέραν γίγνεσθαι ἀμαυροτέραν, ὥστε καὶ τὴν τρίτην ἀνάκλασιν πάμπαν ἀσθενῆ γίγνεσθαι καὶ ἀδυνατεῖν ἀφικνεῖσθαι πρὸς τὸν ἥλιον.	We have now shown why the rainbow has three colours and that these are its only colours. The same cause explains the double rainbow and the faintness of the colours in the outer one and their inverted order. When sight is strained to a great distance the appearance of the distant object is affected in a certain way: and the same thing holds good here. So the reflection from the outer rainbow is weaker because it takes place from a greater distance and less of it reaches the sun, and so the colours seen are fainter. Their order is reversed because more reflection reaches the sun from the smaller, inner band. For that reflection is nearer to our sight which is reflected from the band which is nearest to the primary rainbow. Now the smallest band in the outer rainbow is that which is nearest, and so it will be red; and the second and the third will follow the same principle. Let B be the outer rainbow, A the inner one; let R stand for the red colour, G for green, V for violet; yellow appears at the point Y. Three rainbows or more are not found because even the second is fainter, so that the third reflection can have no strength whatever and cannot reach the sun at all.

Postquam philosophus ostendit causam et modum generationis coloris punicei, consequenter assignat causam et modum generationis aliorum. Et circa hoc duo facit: primo assignat causam colorum principalium; secundo cuiusdam alterius coloris minus principalis, ibi: xanthos autem et cetera. Circa primum duo facit: primo praemittit quasdam suppositiones necessarias ad propositum; secundo ex talibus suppositionibus concludit propositum, ibi: qui quidem igitur et cetera. Circa primum igitur dicit, quod postquam dictum est de uno colore, simul etiam ex dicendis manifestum erit de aliis. Sed oportet prius supponere quaedam. Et primo, quod sicut dictum est, lucidum sive fulgidum, apparens in nigro per refractionem, sive per nigrum tanquam per medium, facit apparitionem coloris punicei, maxime si alteratio fulgidi sit fortis. Secundo supponendum est, quod visus de longe videns obiectum, debilius et minus videt quam videns de prope. Et huius ratio est, quia omne agens naturale debilius agit in multum distans quam in propinquum, et ex consequenti visibile debilius alterat visum a remotis quam de propinquo, convenienti scilicet propinquitate. Tertia suppositio est, quod nigrum in genere colorum est velut privatio, respectu albi praesertim: contraria enim reducuntur ad privativa, et semper alterum contrariorum habet rationem habitus et perfectioris respectu alterius, alterum vero rationem privationis et imperfecti respectu primi, sicut declaratur X Metaphys. Ex quo sequitur, quod illud quod videtur visu existente debili et deficiente, apparet nigrum; quia sicut se habet album ad nigrum, ita se habet visio albi ad visionem nigri, et visus comprehendens unum ad visum comprehendentem reliquum: igitur si unum est velut privatio, reliquum etiam erit tale. Quarta suppositio, quae est magis propinqua proposito, est quia omnia quae videntur a longe, apparent nigriora quam si viderentur de prope. Cuius causa est secundum mathematicos, quia visus non pertingit ad illa, aut debiliter pertingit. Sed secundum veritatem causa est, quia visibile a remotis minus movet quam de propinquo, sicut dictum est in secunda suppositione, ex qua quasi corollarie concluditur ista. Dicit tamen Aristoteles quod de his diligentius considerandum est in libris de sensu et sensato, et in perspectivis, quia illorum est proprium facere considerationem de istis. Propter causam praedictam igitur ea quae videntur de longe, apparent nigriora, minora et planiora. Causa primi dicta est. Sed causa secundi est, quia sicut supra dictum est, visibile emittit radios ad visum quasi pyramidaliter, et basis pyramidis est in ipso visibili, conus autem, qui, est ille angulus acutus pyramidis, terminatur ad visum. Quanto autem magis obiectum distat a visu, tanto magis pyramis protrahitur et fit longior, et facit minorem angulum in oculo, et ex consequenti videtur minor. Causa autem tertii est, quia visus a remotis non potest percipere modicam supereminentiam vel concavitatem, propter debilem alterationem: ex quo omnia astra apparent planae figurae. Et nubes visae per refractionem in aqua tanquam in quodam speculo, nigriores videntur quam visae in seipsis. Quod est signum quod ea quae videntur per refractionem, videntur nigriora: quia scilicet debilius immutant visum. Addit autem quod nihil differt quantum ad praesens propositum, dicere quod visibile immutat visum in visione, quod verum est, aut dicere quod visus permutat visibile, sicut dicebant mathematici antiqui: quia utroque modo accidit idem quod dictum est. Quinta suppositio est, quod nubes quanto fuerit propinquior soli, tanto minus est colorata colore iridis, sed apparet alba, quia tunc magis recipit lumen; sed visa in aqua per refractionem apparet nigrior propter distantiam, et ideo tunc videtur habere aliquem colorem iridis. Ex quibus omnibus ultimate concludit, manifestum esse quod alba visa per refractionem, tum propter maiorem distantiam obiecti, tum quia radii refracti sunt debiliores quam directi, videntur minus alba et quasi tendentia ad nigredinem, quia debilitatio radii facit apparere minus colorem album.

Deinde cum dicit: qui quidem igitur etc., ex dictis suppositionibus concludit causam aliorum colorum apparentium in iride. Et dicit quod ubi est fortior et intensior actio fulgidi in nubem propter minorem distantiam, ibi permutatur color clarus solis in puniceum, qui est propinquior albo: fulgidum enim visum in nigro videtur puniceum, sicut dicit secunda suppositio. Et talis refractio fit in prima peripheria iridis. Sed refractio facta a secunda peripheria adhuc est debilior propter maiorem distantiam, et ideo in ea apparet color viridis, qui est propinquior nigro quam puniceus. Et in tertia circumferentia apparet halurgus, quia etiam est propinquior nigro quam viridis, propter eandem causam.

Deinde cum dicit: quoniam autem quod etc., assignat rationem numeri colorum iridis. Et dicit quod numerus colorum iridis statum habet in tribus, et non procedit ultra: sicut in pluribus aliis naturalibus terminus est in tribus, ut patet I caeli. Permutatio autem si qua alia fit in aliis partibus nubis, est insensibilis, et non facit apparere alium colorem praeter istos. Ratio autem quare sunt tantum tres colores in iride, est quia tot sunt ibi colores, quot sunt loca in nube a quibus fit diversa refractio: sed illa sunt tantum tria, ut iam declaratum est, scilicet supremus, medius et infimus, a quibus diversimode refrangitur lumen.

Deinde cum dicit: propter quod et iris etc., ostendit ordinem et positionem colorum in iride. Et dicit quod quandoque apparent duae irides, et utraque habet praedictos colores, licet e contrario positos: quia interior et contenta, quae est principalior, habet in maiori peripheria colorem puniceum, in media viridem, in infima halurgum, idest caeruleum; sed exterior propter maiorem propinquitatem ad solem, ut dictum est, in minori peripheria habet puniceum, in media viridem, et in suprema halurgum. Deinde recapitulat ea quae dicta sunt, et dicit quod si, pro quia, ea quae prius supposita sunt de apparitione coloris, sunt bene dicta, necesse est in iride apparere tres colores tantum, et nubem colorari solum tribus coloribus, propter rationes quae dictae sunt.

Deinde cum dicit: xanthos autem etc., determinat de causa apparitionis cuiusdam coloris minus principalis, qui apparet aliquando inter puniceum et viridem, et est propinquior albo quam puniceus. Dicitur autem Graece xanthos, Latine autem citrinus. Dicit ergo quod xanthos apparet interdum in iride, non quidem per refractionem: quia tunc essent plures colores principales quam tres, et etiam talis color tunc deberet apparere plus niger quam albus; sed causatur ille color per iuxtapositionem punicei et viridis, quia puniceum positum iuxta viride album videtur: contraria enim iuxta se invicem posita videntur maiora et manifestiora. Hoc autem probat philosophus per quatuor signa. Et primo, quia quando apparet iris in nube spissa et valde nigra, tunc colores videntur maxime puri, et propter hoc xanthos apparet intensior: quod signum est quod xanthos fit per iuxtapositionem punicei et viridis. Et tunc etiam xanthos magis apparet quam puniceus, ex eo quod nubes in parte exteriori per circuitum nigra, propter iuxtapositionem punicei et nigri facit apparere puniceum album, et ex consequenti xanthos positus inter album et viridem, magis apparet, et puniceus magis occultatur. Secundum signum est, quia marcescente nube, idest evanescente, quia tunc rarefit et perdit obscuritatem et nigredinem, tunc puniceus fit albior et mutatur in xanthos, propter iuxtapositionem albi et viridis. Tertium et maximum signum est, quia in iride facta a luna in nocte, omnes colores apparent albiores, et maxime apparet xanthos; quia tunc propter obscuritatem noctis additam nigredini nubis, colores nigri maxime videntur obscuri, et ideo per iuxtapositionem nigri maioris color puniceus videtur albior et citrinus: quia nigrum additum nigro facit album iuxtapositum apparere magis album, sicut ignis vel lumen additum lumini facit e converso nigrum iuxtapositum apparere magis nigrum. Quartum signum est, quia textores texentes flores in pannis sericeis vel alterius generis, diversimode ponunt iuxta se colores, secundum quod volunt causare apparentias diversas in diversis floribus vel figuris. Et hoc etiam observant pictores: nam aliam apparentiam habet color purpureus positus in lana vel serico albo quam positus in nigro, et melius apparet aurum positum in azzurino quam in albo: quod non esset, nisi colores iuxtapositi aliis coloribus magis apparerent et variarent in apparentiis. Colores etiam aliter et aliter positi ad lucernam, idest ad lumen, secundum experientiam variantur propter diversam iuxtapositionem luminis: propter quod saepe accidit quod homines decipiuntur circa colores, propter diversam positionem colorum iuxta se invicem. Deinde epilogat, dicens quod dictum est propter quid iris habet tres colores principales, et quartum minus principalem, et quare iste, vel quartus, appareat inter praedictos colores.

Deinde cum dicit: dupla autem etc., assignat causam quorundam dictorum prius de iride. Dictum est enim supra, quod irides sunt duae tantum, quarum una est continens, altera contenta: sed continens, idest exterior, habet colores obscuriores, et modo contrario positos. Ratio primi est, quia reflexio iridis superioris est remotior, tum a sole illuminante tum etiam ab oculo, sicut dictum est: ideo est debilior, et colores videntur obscuriores. Causa autem secundi, quia quanto magis reflexio est debilis, tanto color est nigrior, et e converso; sed maior circumferentia exterioris iridis est remotior, et ex consequenti reflexio est debilior; et ideo in ea est color halurgus, quia est magis obscurus, in secunda vero eiusdem iridis, quae est minus remota, est color viridis, in tertia adhuc minus remota, puniceus. Sed in interiori maior peripheria est propinquior: ideo in ea est color puniceus, in secunda, quae est minus propinqua, est viridis, in tertia vero adhuc magis remota, est color halurgus. Quae omnia satis manifesta sunt absque alia deductione in terminis communibus. Dicit autem quod ut in pluribus non apparent plures irides duabus: quia ascendendo et descendendo a medio nubis, propter nimiam elongationem semper refractio debilitatur, ita quod ultra tres colores refractio non pertingit ad visum nostrum, quia a remotiori semper fit debilior refractio.

Sed ad maiorem evidentiam illorum quae Aristoteles dixit de coloribus iridis, oportet quaedam considerare. Primo quidem, utrum colores iridis sint colores secundum rei veritatem, an tantum secundum apparentiam. Secundo, in quo sint colores iridis sicut in subiecto. Tertio, utrum id quod continetur inter minorem peripheriam iridis et maiorem, sit coloratum vel non. Quarto, utrum medium quod interiacet duabus iridibus, sit coloratum colore puniceo. Quinto, utrum possibile sit aliquando tertiam apparere iridem, et propter quam causam. Sexto videndum est de causa cuiusdam iridis quae apparet, alio modo se habente nube ad solem quam Aristoteles dixit, sicut videbitur. Et ad evidentiam primi, quia colores iridis causantur ex refractione luminis a corporibus specularibus, primo videndum est utrum lumen in medio sit aliqua qualitas, an non. Secundo, utrum lumen refractum in corpore speculari, faciat in ipso a quo refrangitur apparentiam alicuius coloris non existentis prius in eo secundum quod huiusmodi, aut recipiat ab eo, vel non. Primo ergo quaerendum est, utrum lumen sit in medio secundum esse reale, aut tantum secundum esse intentionale. Et videtur quod tantum habeat esse intentionale: quia quod habet esse reale in alio, manet in ipso post absentiam generantis, sicut in simili, calidum et frigidum manent in eis in quibus fiunt, in absentia generantis; sed amoto corpore luminoso, lumen non remanet in medio; ergo et cetera. Secundo: sensibile positum supra sensum secundum esse reale, nullam facit sensationem, sicut habetur in II de anima; sed lumen in medio existens vel in sensu, facit sensationem in actu; ergo non habet ibi esse reale. Praeterea: omnis forma realiter recepta in materia inferiorum, habet contrarium; sed luminis in medio nihil est contrarium; ergo non est realiter receptum in medio. Maior probatur: quia in hoc differunt materia corporum superiorum et inferiorum, quia materia superiorum habet formam quae complet totum eius appetitum, et ideo non est susceptiva contrariorum, sed materia inferiorum recipit formam non complentem totum eius appetitum: ergo est susceptiva contrariorum, et forma recepta in ea realiter, habet contrarium. Pro huius igitur intelligentia sciendum est, quod lumen in medio habet esse intentionale, quia causat sensationem; sed non solum habet ibi esse intentionale, sed etiam habet esse reale et naturale, licet tale esse reale debilius sit et minus permanens in medio quam in corpore luminoso. Et hoc multipliciter probari potest. Primo: quia quae habent unum receptivum secundum naturam, habent etiam idem esse reale et eundem modum essendi; sed lumen in corpore luminoso et in medio illuminato ab eo, habet idem receptivum, scilicet perspicuum: quia lumen per se est actus diaphani secundum quod huiusmodi; ergo habet idem esse; ergo si in uno habet esse reale, et in reliquo. Maior probatur: quia ad unitatem unius per se relativi sequitur unitas alterius; sed receptibile et receptum dicuntur relative; ergo si susceptibile luminis est unum, et lumen erit unum, et habebit unum esse. Confirmatur minor primi argumenti: quia diaphanum in corporibus inferioribus est eiusdem naturae, differens solum secundum magis et minus, sicut in simili, in corporibus superioribus diaphanum in parte stellata et in parte non stellata est idem secundum naturam, differens secundum magis et minus densum. Praeterea secundo: quorum est una operatio prima, horum est una natura, et ex consequenti unum esse; sed lucis in corpore luminoso et in medio illuminato est una operatio prima, illuminare scilicet perspicuum; ergo si lux in uno est qualitas realis, et in altero. Maior patet: quia operatio consequitur formam, sicut transmutatio materiam. Praeterea: forma aliqua in eo habet esse reale et naturale, in quo generatur ab agente secundum naturam, secundum quod huiusmodi, per reductionem de potentia naturali ad actum; sed lumen est tale in medio; ergo habet ibi esse reale. Maior est nota, et manifeste ostendit a priori aliquid habere esse reale. Minor vero probatur: quia lumen causatur ab agente naturali, scilicet a corpore lucido, per reductionem medii de potentia naturali, qua erat lucidum in potentia, ad esse lucidum in actu. Deinde: illud quod habet operationem realem et naturalem secundum quod huiusmodi, videtur habere etiam esse reale et naturale: quia unumquodque operatur secundum quod est (IX Metaphys.), et operatio consequitur esse; sed lumen in medio habet operationem realem et naturalem, sicut illuminare, calefacere et huiusmodi: sicut sensus docet, et scientia de speculis comburentibus supponit. Quod autem lumen in medio habeat debilius esse quam in corpore lucido, satis manifestum est: quia medium quod est perspicuum, est rarum, et lumen propter raritatem medii facile pertransit, et non est multae permanentiae in eo; sed in corpore illuminato est densitas, quae corpus lucidum et etiam lumen aliqualiter terminat, et propter densitatem talis corporis lumen in eo est maioris permanentiae. Et in signum huius, lumen existens in medio debilius operatur quam existens in corpore lucido vel illuminato; debilior autem operatio consequitur debilius esse: quia modus operandi consequitur modum essendi. Et propter hoc, si aliquis huiusmodi esse debilius vocet esse intentionale, coincidit secundum rem nobiscum, et nomine tantum differens est: de qua differentia non est curandum inquirentibus veritatem. Ad primum autem in oppositum dicendum est, quod sensibile extra sensum habens esse firmum, quia excellenter movet sensum, ideo positum supra sensum non movet sensum ad actum, sed magis ipsum corrumpit propter suam disproportionem ad sensum: quia sensus consistit in quadam medietate vel harmonia; sed tamen sensibile receptum in medio, sub esse reali debiliori quod proportionatur sensui, potest in ipso habere esse etiam intentionale, et movere ipsum ad sensationem in actu. De sensibili autem primo modo, cuiusmodi est lumen in corpore lucido, loquebatur philosophus. Ad secundum, non est difficile illud solvere, quia est duplex generans: unum quod est principium transmutationis rei generatae tantum, et non conservationis ipsius esse, sicut domificator est causa factionis domus: aliud est generans, quod cum hoc est causa conservationis rei generatae, quemadmodum locus est causa rei locatae per se; effectus autem manet post absentiam generantis primo modo, non autem post absentiam generantis secundo modo. Eiusmodi est corpus lucidum. Ad tertium dicendum, quod contraria dicuntur dupliciter. Uno modo sumitur contrarietas proprie, pro repugnantia duarum formarum aequaliter et maxime distantium sub eodem genere: sicut calidum et frigidum distant et per se contrariantur. Alio modo accipiuntur contraria, prout extendunt se ad principia opposita: sicut forma et privatio interdum dicuntur contraria; et hoc modo intelligitur quod forma recepta in materia horum inferiorum habet contrarium, non autem primo modo. Sed hoc modo lumen habet contrarium, quia habet privationem oppositam.

Secundo videndum est, utrum lumen in eo corpore a quo refrangitur, sit principium alicuius coloris non praeexistentis. Et videtur quod non: quia si lumen refractum in eo a quo refrangitur, esset per se principium alicuius coloris, sequeretur quod a quocumque fieret refractio et in quocumque situ, semper causaret talem colorem; sed hoc est falsum, ut ad sensum videtur; ergo lumen refractum per se non est principium alicuius talis coloris. In contrarium est, quia sensus docet quod lumen incidens corpori pervio spisso, colorato aliquo colore, puta rubeo, facit ea a quibus refrangitur apparere per illud colore vergente ad colorem illius. Etiam ea quae videntur in speculis viridibus, videntur sub lumine refracto consimilis coloris. Sed tamen quomodo hoc fiat intelligendum est, quod color causatur ex praesentia luminis in perspicuo terminato per opacum, et secundum diversam proportionem luminis ad opacum in perspicuo diversificantur colores, quia ex multo lumine et pauco opaco causatur color albus, et e converso color niger; sed medii colores fiunt secundum proportiones medias: propinquiores quidem albo in plus habendo de lumine et minus de opaco, et propinquiores nigro causantur opposito modo. Ex quibus patet, quod appositio luminis ad opacum, vel e contra, secundum aliam et aliam quantitatem, variat colores. Ex quo sequitur ad propositum, quod lumen generatum a corpore luminoso, secundum rectum incidens alicui corpori aspero habenti aliquem colorem in actu vel in virtute, ita quod a profundo eius refrangitur, si fuerit multum lumen, illuminat tale corpus secundum partem cui incidit, fortius quam esset illuminatum ante, et mutat in ipso colorem praeexistentem sensibiliter secundum diversam proportionem eius ad opacum, et per consequens facit ibi apparitionem alicuius coloris non praeexistentis. Sed quando lumen refrangitur a prima superficie talis corporis propter lenitatem, ita quod lumen non recipiatur in profundo, tunc generatur phantasia, idest apparitio coloris, debilior tamen: quia in parte in qua incidit lumen, fit fortior illuminatio corporis a quo fit refractio luminis ad visum, et propter huiusmodi fortificationem coloratur non tantum corpus sed etiam lumen colore proprio corporis, vergente aliquantulum ad clarum, propter adiunctionem luminis ipsius. Et secundum hunc modum corpus a quo fit refractio, videtur alterius coloris quam fit ordinarie. Si vero corpus cui incidit lumen, non habeat aliquem colorem proprium, sed solum naturam perspicui, tunc nulla fiet phantasia coloris, propter defectum opaci. Ad rationem autem in oppositum dicitur quod verum concludit, quando lumen in corpore a quo refrangitur, invenit opacum actu vel virtute. Sed hoc opacum non invenit in omni eo a quo refrangitur: et ideo non causat in omnibus talem apparentiam colorum, quia sine opaco non possunt fieri. Quare autem lumen faciat magis apparere colores quam magnitudinem vel figuram corporis a quo refrangitur, partim patet ex dictis, et melius manifestabitur in sequentibus.

Quaeritur tertio, utrum colores iridis habeant rationem veri coloris. Et primo arguitur quod non: quia quod causatur ex sola refractione luminis ad visum, non videtur verus color, sed apparens tantum; colores autem iridis secundum Aristotelem causantur ex sola refractione; ergo non sunt veri colores. Praeterea: si tales apparentiae essent veri colores, deberent apparere in quocumque situ, sicut apparet de his quae colorantur secundum veritatem; sed sic non est de coloribus iridis; ergo non sunt veri colores. Praeterea: quod causatur ex debilitate visus, non est color secundum veritatem; sed colores iridis causantur ex debilitate visus; ergo non sunt colores secundum veritatem. Intelligendum igitur est, quod colores iridis habent essentiam veri coloris, debiliter tamen et imperfecte, sicut lumen in medio respectu luminis in corpore luminoso; quia quod est motivum visus secundum se, hoc est color secundum veritatem: quia color secundum philosophum II de anima, est quod est motivum visus secundum se; sed colores iridis sunt huiusmodi, sicut sensus iudicat; ergo sunt veri colores. Secundo: quia veritas rei idem est quod essentia rei, differens solum secundum rationem; sed colores iridis habent essentiam et formam coloris, licet secundum esse debile; ergo habent veritatem coloris. Minor probatur: quia sensus visus qui hoc iudicat, non decipitur circa proprium sensibile. Tertio: id quod visus iudicat se apprehendere per se primo, est color secundum veritatem, qui est obiectum visus: quia sensus proprius circa proprium et per se obiectum non decipitur; sed in visione iridis visus iudicat se videre verum colorem; ergo et cetera. Amplius: ubicumque sunt principia veri coloris secundum veritatem, ibi est forma et essentia veri coloris secundum veritatem; sed in iride actu concurrunt omnia principia coloris secundum veritatem; ergo et cetera. Maior est nota: quia causa et effectus in actu sunt simul in actu (II Physic.). Minor probatur: quia principium veri coloris in actu, est perspicuum aliquo modo terminatum in ratione materiae, et lumen ibi existens actu in ratione formae; sed ista ambo sunt actu in iride, sive in eo in quo apparet iris: quia perspicuum aequaliter est terminatum per opacum in roratione descendente sub nube, in qua generatur iris, aliter non haberet rationem speculi refrangentis: lumen vero a sole vel a luna incidens illi, habet rationem formae; ergo sequitur, quod cum in iride sint actu omnia principia veri coloris, sint ibi veri colores: licet color ibi habeat esse debile, sicut dictum est, quia principia eius non sunt ita permanentia sicut in corporibus mixtis terminatis, in quibus principia coloris consequuntur principia intrinseca corporis mixti, et sunt ei intrinseca: consequuntur enim ipsa miscibilia, quae sunt permanentia actu vel virtute, et per consequens et color ex ipsis causatus est permanens et perfectus. Sed non est sic de coloribus iridis, quia lumen ibi est extrinsecum, et solum incidit secundum determinatum situm ad visum, et secundum quod incidit diversimode causat diversos colores, qui apparent transferri per motum ipsius visus; et tamen secundum veritatem non transferuntur, quia in aliis partibus rorationis de novo continue generantur. Ad obiecta autem dicendum est: et ad primum, quod color potest causari ex refractione, vel ex concurrentibus ad refractionem luminis ad visum, sicut dictum est: sed non color secundum esse perfectum et fixum, propter variationem refractionis. Sed si staret corpus luminosum et nubes in eadem distantia et dispositione, iris haberet esse permanens. Ad secundum dicendum est, quod assumptum verum est de coloribus habentibus esse firmum et fixum in subiecto, non autem de coloribus apparentibus per refractionem, quae non fit nisi ex opposito, vel quasi ex opposito, existente luminoso. Ad tertium dico quod color qui totaliter causatur ex debilitate visus, non est verus color: quia tale est pura privatio, sicut remotio luminis est privatio. Sed falsum est quod colores iridis causentur totaliter ex debilitate visus, quia causantur primo ex lumine incidente rorationi. Est tamen verum quod debilitas visus, sicut et remotio luminis, facit ad hoc quod colores appareant obscuriores.

Quarto quaeritur, utrum colores iridis sint subiective in partibus specularibus rorationis. Et videtur quod non: quia color videtur esse ibi, ubi visus iudicat ipsum esse; sed visus eum iudicat esse in nube, non in partibus rorationis; ergo et cetera. Secundo: simile iudicium videtur esse de idolo apparente in speculo, et de colore iridis, quia ambo apparent per refractionem; sed idolum apparens in speculo non dicitur esse in eo, sed in corpore; ergo color iridis non est in corporibus specularibus, sed in sole vel astro, ex quorum refractione apparet. In oppositum est tamen, quod in illo sunt colores iridis sicut in subiecto, in quo concurrunt actu principia ipsorum, sicut in simili, in eo sunt sapores sicut in subiecto, in quo concurrunt principia saporis actu; sed principia coloris iridis sunt perspicuum partium rorationis aliquo modo terminatum per opacum, et lumen incidens ei et refractum ab ipso, quae simul concurrunt in dictis partibus rorationis sub nube existentis; ergo colores sunt ibi sicut in subiecto, et non sunt in ipsa nube nigra: licet appareant secundum sensum ibi esse, quia visus propter nimiam distantiam eorum ab oculo non percipit remotionem unius ab altero. Quando enim aliquod corpus distans videtur per alterum vel iuxta alterum, tunc apparet esse in eadem superficie cum ipso, et propter eandem causam omnia a remotis visa videntur plana, sicut dicebatur prius; sed nubes videtur per iridem, vel iuxta iridem: et per consequens videtur in eadem superficie cum ipsa. Ad primum dicitur, quod aliud est subiectum colorum iridis et idolorum universaliter apparentium ex refractione, secundum veritatem, et aliud locus in quo apparent esse secundum sensum: quia colores iridis sunt in partibus rorationis specularibus sicut in subiecto, secundum veritatem, sed sunt in nube solum secundum apparentiam, quod concessum est. Ad secundum dicitur, quod similitudo potest concedi, sed illud quod assumitur, quod idolum non sit in superficie speculari a qua fit refractio, sed sit in corpore obiecto, negandum est: quia species visibilis, vel figura visibilis illius cuius est idolum, in quod fertur visus mediante specie, est in eo secundum esse fixum et permanens, sed tamen est in superficie speculi a quo fit refractio, secundum aliud esse, et est quodammodo in medio secundum lineam rectam. Sic in proposito, lumen ex cuius refractione generatur iris, secundum esse magis reale est in corpore luminoso, sed secundum aliud esse eius est in corpore illuminato, et in corpore a quo refrangitur, in quo per admixtionem perspicui terminati facit aliquem colorem ibi existentem.

Quinto quaeritur, utrum illud quod continetur intra minorem peripheriam iridis, et id quod est supra maiorem, sit coloratum vel non. Videtur quod sic: quia ubi est eadem causa, ibi est idem effectus; sed causa coloris videtur esse eadem intra minorem et supra maiorem peripheriam iridis, sicut in illa parte ubi apparet iris, scilicet refractio luminis stellae a roratione descendente sub nube; ergo videtur quod illa pars sit colorata. Respondetur quod illud est coloratum colore nigro nubis, quia halurgus, qui est in minori peripheria iridis et est propinquior nigro, disparet in nigrum: et hoc etiam sensus docet; sed non est coloratum aliquo colore iridis sensibiliter diverso a colore nubis. Cuius ratio est, quia ad hoc quod appareat aliquis color irialis sensibilis ex refractione luminis solis a roratione opposita, oportet refractionem esse multam et fortem secundum philosophum; sed ab illo loco non fit multa refractio et fortis: non multa, propter parvitatem illius intermedii, nec fortis, quia a partibus perpendicularibus vel propinquioribus perpendiculari, debilius refranguntur radii et ad minorem angulum. Et propter hoc philosophus, ubi dat naturam colorum iridis, dicit quod ab illa parte est permutatio insensibilis colorum. Ad rationem in contrarium dicendum est, quod minor est falsa: non enim quaecumque refractio est causa coloris iridis, sed oportet ipsum lumen multiplicatum esse forte: refractio autem quae fit ab illo loco, est debilis.

Sexto quaeritur, utrum medium duarum iridum sit puniceum. Ad quod respondet Alexander in commento, quod non est ibi aliquis color: quia color in iride causatur a determinata distantia et situ determinato inter solem et visum; sed talis secundum eum non est in tali parte intermedia; ergo ab ipsa non est talis refractio, et per consequens non mutat ipsam ad aliquem colorem. Et confirmatur: quia sensus non iudicat de illo colore intermedio; ergo videtur quod non sit ponendus. Sciendum est tamen, quod maior nunc assumpta vera est, sed falsa est minor: quia non videtur rationabile neque consonans rationi, quod a superiori iride et remotiori, et similiter ab inferiori et propinquiori possit fieri refractio sensibilis, et quod non fiat a parte intermedia, si fuerit materia disposita, sicut hic supponitur; sicut in simili, si accipiantur tria specula, in tali distantia ad se invicem et ad corpus obiectum secundum aliquam proportionem, qualis est distantia duarum iridum et partis intermediae ad se invicem et ad solem et ad visum, si fit refractio corporis obiecti a duobus speculis extremis ad visum, et apparitio idoli, tunc etiam fit a speculo intermedio, ut patet ad sensum. Et confirmatur: quia omnia ad colorem talem requisita possunt concurrere in tali intermedio, scilicet refractio fortis et multum luminis, si sit roratio disposita in medio sicut in extremis: immo fit maior quam in peripheria maiori minoris iridis, et etiam fit propinquior et maior quam in peripheria minori exterioris iridis. Est ergo dicendum, quod in illa parte intermedia non est color puniceus, sed est alius color secundum aliquid propinquior albo vel clarior quam sit puniceus, quia plus obtinet de lumine per iuxtapositionem illorum duorum puniceorum, quam puniceus in minori peripheria superioris vel in maiori inferioris. Et ex hoc iste color in parte intermedia est albior et clarior. Ad id autem quod in oppositum inducebatur de sensu, dicendum quod iste color, propter eius claritatem et non multam differentiam a puniceo, vix discernitur a visu in tanta distantia, nisi subtiliter intuenti: sed tamen sensus non iudicat oppositum. Et hoc apparet ex eo, quia in medio duarum iridum apparet quaedam citrinitas clara valde; sed color citrinus est propinquior claro et albo quam puniceus, sicut dictum est prius, et inter duos puniceos positus adhuc magis claret.

Septimo videndum est, utrum possibile sit apparere simul plures irides duabus. Et videtur quod non: quia Aristoteles supra dixit, quod propter remotionem secunda iris habet colores debiliores quam prima; sed situs tertiae est multo remotior; ergo etiam refractio erit debilior, adeo quod non poterit causare apparentiam alicuius coloris sensibilis. Dicimus tamen ad quaestionem, quod non est impossibile apparere tertiam iridem, licet hoc raro contingat. Et talis iris se habet secundum situm ad secundam, sicut secunda ad primam, et habet obscuriores colores coloribus secundae, sicut secunda respectu primae, propter eandem causam. Et talis iris apparet propter eandem causam propter quam duae aliae apparent, scilicet propter refractionem luminis ad visum. Et tunc causatur, quando nubes opposita soli est multum nigra et spissa, quia tunc potest facere multam et bene dispositam rorationem ad refractionem. De ordine autem colorum istius iridis experimentum non habui; rationabiliter tamen videtur quod haberet colores ordine contrario cum coloribus secundae, scilicet halurgum in minori peripheria, viridem in secunda et puniceum in maiori, sicut prima: quia omnis processus fit per assimilationem secundorum ad prima; sed halurgus qui est in maiori peripheria secundae, est propinquior nigro; igitur rationabiliter in minori peripheria tertiae deberet apparere color halurgus, qui est propinquior nigro: et deinde in secunda viridis, qui est propinquior huic: deinde in tertia puniceus, qui disparet in albo vel claro nubis subtilioris in extremitate. Ad rationem in contrarium dicitur, quod dictum Aristotelis intelligendum est ut in pluribus, quia raro videtur tertia. Consequentia autem absolute non valet: quia potest esse quod refractio continue fiat debilior, quanto nubes est remotior, et tamen roratio in qua fit tertia iris, non sit ita remota quod non possit colorari a lumine refracto in ipsa.

Quaeritur octavo, utrum non existente nube possit interdum apparere iris in superficie maris. Videtur quod non: iris enim causatur ex refractione luminis a roratione sub nube opposita, visu existente in medio; sed in ista apparitione navigantibus facta, talia non habent locum, ut suppositum est; ergo non potest ibi fieri iris. Sciendum est autem quod quandoque, existente caligine in superficie maris non multum elevata, apparuit iris navigantibus lateraliter, habens omnes colores iridis: et tamen erat nubes. Videbatur autem navigantibus transferri, semper apparens ipsis in eadem distantia et situ ad ipsos, usque ad defectum caliginis, quia semper ab alia et alia parte fiebat continue alia et alia refractio ad visum. Ad rationem in oppositum dicitur, quod omnia ista in praedicta apparitione assignari possunt: quia superior pars caliginis, incidentibus radiis solaribus antiperistasim passa, convertebatur in subtilem rorationem, cuius partes habent rationem speculi, in quo possibile est apparere colorem corporis obiecti, non autem figuram, sicut dicebatur prius. Sed mare ex opposito navigantium existens, apparens navigantibus altius, et habens circa terram figuram circularem, non planam, cum sit aqua pura et a remotis videatur repraesentare colorem nigrum, quemadmodum nubes, habet rationem nubis; lumen vero factum a sole vel ab aliqua stella, et refractum ad visum a nigredine maris altioris per subtilem rorationem caliginis, habebat rationem refracti ad visum: et propter hoc causabat figuram iridis et colores.

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Lectio 7

5	5
ὅτι δ' οὔτε κύκλον οἷόν τε γενέσθαι τῆς ἴριδος οὔτε μεῖζον ἡμικυκλίου τμῆμα, καὶ περὶ τῶν ἄλλων τῶν συμβαινόντων περὶ αὐτήν, ἐκ τοῦ διαγράμματος ἔσται θεωροῦσι δῆλον. ἡμισφαιρίου γὰρ ὄντος ἐπὶ τοῦ ὁρίζοντος κύκλου τοῦ ἐφ' ᾧ τὸ Α, κέντρου δὲ τοῦ Κ, ἄλλου δέ τινος ἀνατέλλοντος σημείου ἐφ' ᾧ τὸ Η, ἐὰν ἀπὸ τοῦ Κ γραμμαὶ κατὰ κῶνον ἐκπίπτουσαι ποιῶσιν ὡσπερεὶ ἄξονα τὴν ἐφ' ᾗ ΗΚ, καὶ ἀπὸ τοῦ Κ ἐπὶ τὸ Μ ἐπιζευχθεῖσαι ἀνακλασθῶσιν ἀπὸ τοῦ ἡμισφαιρίου ἐπὶ τὸ Η ἐπὶ τὴν μείζω γωνίαν, πρὸς κύκλου περιφέρειαν προσπεσοῦνται αἱ ἀπὸ τοῦ Κ καὶ ἐὰν μὲν ἐπ' ἀνατολῆς ἢ ἐπὶ δύσεως τοῦ ἄστρου ἡ ἀνάκλασις γένηται, ἡμικύκλιον ἀποληφθήσεται τοῦ κύκλου ὑπὸ τοῦ ὁρίζοντος τὸ ὑπὲρ γῆν γιγνόμενον, ἐὰν δ' ἐπάνω, ἀεὶ ἔλαττον ἡμικυκλίου ἐλάχιστον δέ, ὅταν ἐπὶ τοῦ μεσημβρινοῦ γένηται τὸ ἄστρον.	The rainbow can never be a circle nor a segment of a circle greater than a semicircle. The consideration of the diagram will prove this and the other properties of the rainbow. Let A be a hemisphere resting on the circle of the horizon, let its centre be K and let H be another point appearing on the horizon. Then, if the lines that fall in a cone from K have HK as their axis, and, K and M being joined, the lines KM are reflected from the hemisphere to H over the greater angle, the lines from K will fall on the circumference of a circle. If the reflection takes place when the luminous body is rising or setting the segment of the circle above the earth which is cut off by the horizon will be a semi-circle; if the luminous body is above the horizon it will always be less than a semicircle, and it will be smallest when the luminous body culminates.
ἔστω γὰρ ἐπ' ἀνατολῆς πρῶτον, οὗ τὸ Η, καὶ ἀνακεκλάσθω ἡ ΚΜ ἐπὶ τὸ Η, καὶ τὸ ἐπίπεδον ἐκβεβλήσθω ἐν ᾧ ἡ Α, τὸ ἀπὸ τοῦ τριγώνου ἐν ᾧ τὸ ΗΚΜ. κύκλος οὖν ἡ τομὴ ἔσται τῆς σφαίρας ὁ μέγιστος. ἔστω ὁ ἐφ' ᾧ Α διοίσει γὰρ οὐδὲν ἂν ὁποιονοῦν τῶν ἐπὶ τῆς ΗΚ κατὰ τὸ τρίγωνον τὸ (376a.) ΚΜΗ ἐκβληθῇ τὸ ἐπίπεδον. αἱ οὖν ἀπὸ τῶν Η Κ ἀναγόμεναι γραμμαὶ ἐν τούτῳ τῷ λόγῳ οὐ συσταθήσονται τοῦ ἐφ' ᾧ Α ἡμικυκλίου πρὸς ἄλλο καὶ ἄλλο σημεῖον ἐπεὶ γὰρ τά τε Κ Η σημεῖα δέδοται καὶ ἡ ΗΚ, δεδομένη ἂν εἴη καὶ ἡ ΜΗ, ὥστε καὶ λόγος τῆς ΜΗ πρὸς ΜΚ. δεδομένης οὖν περιφερείας ἐφάψεται τὸ Μ. ἔστω δὴ αὕτη ἐφ' ἧς τὰ Ν Μ ὥστε ἡ τομὴ τῶν περιφερειῶν δέδοται. πρὸς ἄλλῃ δέ γε ἢ τῇ ΜΝ περιφερείᾳ ἀπὸ τῶν αὐτῶν σημείων ὁ αὐτὸς λόγος ἐν τῷ αὐτῷ ἐπιπέδῳ οὐ συνίσταται.	First let the luminous body be appearing on the horizon at the point H, and let KM be reflected to H, and let the plane in which A is, determined by the triangle HKM, be produced. Then the section of the sphere will be a great circle. Let it be A (for it makes no difference which of the planes passing through the line HK and determined by the triangle KMH is produced). Now the lines drawn from H and K to a point on the semicircle A are in a certain ratio to one another, and no lines drawn from the same points to another point on that semicircle can have the same ratio. For since both the points H and K and the line KH are given, the line MH will be given too; consequently the ratio of the line MH to the line MK will be given too. So M will touch a given circumference. Let this be NM. Then the intersection of the circumferences is given, and the same ratio cannot hold between lines in the same plane drawn from the same points to any other circumference but MN.
ἐκκείσθω οὖν τις γραμμὴ ἡ ΔΒ, καὶ τετμήσθω ὡς ἡ ΜΗ πρὸς ΜΚ ἡ Δ πρὸς Β. μείζων δὲ ἡ ΜΗ τῆς ΚΜ, ἐπείπερ ἐπὶ τὴν μείζω γωνίαν ἡ ἀνάκλασις τοῦ κώνου ὑπὸ γὰρ τὴν μείζω γωνίαν ὑποτείνει τοῦ ΚΜΗ τριγώνου. [μείζων ἄρα καὶ ἡ Δ τῆς Β.] προσπεπορίσθω οὖν πρὸς τὴν Β, ἐφ' ἧς τὸ Ζ ὥστ' εἶναι ὅπερ τὴν Δ πρὸς τὴν Β, τὴν ΒΖ πρὸς τὴν Δ. εἶτα ὅπερ ἡ Ζ πρὸς τὴν ΚΗ, ἡ τὸ Β πρὸς ἄλλην πεποιήσθω τὴν ΚΠ, καὶ ἀπὸ τοῦ Π ἐπὶ τὸ Μ ἐπεζεύχθω ἡ τὸ ΜΠ.	Draw a line DB outside of the figure and divide it so that D:B=MH:MK. But MH is greater than MK since the reflection of the cone is over the greater angle (for it subtends the greater angle of the triangle KMH). Therefore D is greater than B. Then add to B a line Z such that B+Z:D=D:B. Then make another line having the same ratio to B as KH has to Z, and join MI.
ἔσται οὖν τὸ Π πόλος τοῦ κύκλου, πρὸς ὃν αἱ ἀπὸ τοῦ Κ γραμμαὶ προσπίπτουσιν ἔσται γὰρ ὅπερ ἡ Ζ πρὸς ΚΗ, καὶ ἡ Β πρὸς ΚΠ, καὶ ἡ Δ πρὸς ΠΜ. μὴ γὰρ ἔστω, ἀλλ' ἢ πρὸς ἐλάττω ἢ πρὸς μείζω τῆς ΠΜ οὐδὲν γὰρ διοίσει. ἔστω πρὸς ΠΡ. τὸν αὐτὸν ἄρα λόγον αἱ ΗΚ καὶ ΚΠ καὶ ἡ ΠΡ πρὸς ἀλλήλας ἕξουσιν ὅνπερ αἱ Δ Β Ζ. αἱ δὲ Δ Β Ζ ἀνὰ λόγον ἦσαν, ὅνπερ ἡ Δ πρὸς Β, ἡ ΖΒ πρὸς Δ ὥστε ὅπερ ἡ ΠΗ πρὸς τὴν ΠΡ, ἡ τὸ ΠΡ πρὸς τὴν ΠΚ. ἂν οὖν ἀπὸ τῶν Κ Η αἱ ΗΡ καὶ ΚΡ ἐπὶ τὸ Ρ ἐπιζευχθῶσιν, αἱ ἐπιζευχθεῖσαι αὗται τὸν αὐτὸν ἕξουσι λόγον ὅνπερ ἡ ΗΠ πρὸς τὴν ΠΡ περὶ γὰρ τὴν αὐτὴν γωνίαν τὴν Π ἀνάλογον αἵ τε τοῦ ΗΠΡ τριγώνου καὶ τοῦ ΚΡΠ. ὥστε καὶ ἡ ΠΡ πρὸς τὴν ΚΡ τὸν αὐτὸν ἕξει λόγον, καὶ ἡ τὸ ΗΠ πρὸς τὴν ΠΡ. ἔχει δὲ καὶ ἡ ΜΗ πρὸς ΚΜ τοῦτον τὸν λόγον ὅνπερ γὰρ (376b.) ἡ τὸ Δ πρὸς τὴν Β ἀμφότεραι. ὥστε ἀπὸ τῶν Η Κ σημείων οὐ μόνον πρὸς τὴν ΜΝ περιφέρειαν συσταθήσονται τὸν αὐτὸν ἔχουσαι λόγον, ἀλλὰ καὶ ἄλλοθι ὅπερ ἀδύνατον. ἐπεὶ οὖν ἡ Δ οὔτε πρὸς ἔλαττον τοῦ ΜΠ οὔτε πρὸς μείζω (ὁμοίως γὰρ δειχθήσεται), δῆλον ὅτι πρὸς αὐτὴν ἂν εἴη τὴν ἐφ' ᾗ Μ Π. ὥστ' ἔσται ὅπερ ἡ ΜΠ πρὸς ΠΚ, ἡ ΠΗ πρὸς τὴν ΜΠ [καὶ λοιπὴ ἡ τὸ ΜΗ πρὸς ΜΚ].	Then I is the pole of the circle on which the lines from K fall. For the ratio of D to IM is the same as that of Z to KH and of B to KI. If not, let D be in the same ratio to a line indifferently lesser or greater than IM, and let this line be IP. Then HK and KI and IP will have the same ratios to one another as Z, B, and D. But the ratios between Z, B, and D were such that Z+B:D=D: B. Therefore Ih:IP=IP:IK. Now, if the points K, H be joined with the point P by the lines HP, KP, these lines will be to one another as IH is to IP, for the sides of the triangles HIP, KPI about the angle I are homologous. Therefore, HP too will be to KP as HI is to IP. But this is also the ratio of MH to MK, for the ratio both of HI to IP and of Mh to MK is the same as that of D to B. Therefore, from the points H, K there will have been drawn lines with the same ratio to one another, not only to the circumference MN but to another point as well, which is impossible. Since then D cannot bear that ratio to any line either lesser or greater than IM (the proof being in either case the same), it follows that it must stand in that ratio to MI itself. Therefore as MI is to IK so IH will be to MI and finally MH to Mk.
ἐὰν οὖν τῷ ἐφ' ᾧ τὸ Π πόλῳ χρώμενος, διαστήματι δὲ τῷ ἐφ' ᾧ Μ Π, κύκλος γραφῇ, ἁπασῶν ἐφάψεται τῶν γωνιῶν ἃς ἀνακλώμεναι ποιοῦσιν αἱ ἀπὸ τοῦ ΜΑ κύκλου εἰ δὲ μή, ὁμοίως δειχθήσονται τὸν αὐτὸν ἔχουσαι λόγον αἱ ἄλλοθι καὶ ἄλλοθι τοῦ ἡμικυκλίου συνιστάμεναι, ὅπερ ἦν ἀδύνατον. ἐὰν οὖν περιαγάγῃς τὸ ἡμικύκλιον τὸ ἐφ' ᾧ τὸ Α περὶ τὴν ἐφ' ᾗ Η Κ Π διάμετρον, αἱ ἀπὸ τοῦ ΗΚ ἀνακλώμεναι πρὸς τὸ ἐφ' ᾧ τὸ Μ ἐν πᾶσι τοῖς ἐπιπέδοις ὁμοίως ἕξουσι, καὶ ἴσην ποιήσουσι γωνίαν τὴν ΚΜΗ καὶ ἣν ποιήσουσι δὲ γωνίαν αἱ ΗΠ καὶ ΜΠ ἐπὶ τῆς ΗΠ, ἀεὶ ἴση ἔσται. τρίγωνα οὖν ἐπὶ τῆς ΗΠ καὶ ΚΠ ἴσα τῷ ΗΜΠ ΚΜΠ συνεστήκασι. τούτων δὲ αἱ κάθετοι ἐπὶ τὸ αὐτὸ σημεῖον πεσοῦνται τῆς ΗΠ καὶ ἴσαι ἔσονται. πιπτέτωσαν ἐπὶ τὸ Ο. κέντρον ἄρα τοῦ κύκλου τὸ Ο, ἡμικύκλιον δὲ τὸ περὶ τὴν ΜΝ ἀφῄρηται ἀπὸ τοῦ ὁρίζοντος τῶν μὲν γὰρ ἄνω τὸν ἥλιον οὐ κρατεῖν, τῶν δὲ *προσπτεριζομένων* κρατεῖν, καὶ διαχεῖν τὸν ἀέρα καὶ διὰ τοῦτο τὴν ἶριν οὐ συμβάλλειν τὸν κύκλον γίγνεσθαι δὲ καὶ νύκτωρ ἀπὸ τῆς σελήνης ὀλιγάκις οὔτε γὰρ ἀεὶ πλήρης, ἀσθενεστέρα τε τὴν φύσιν ὥστε κρατεῖν τοῦ ἀέρος μάλιστα δ' ἵστασθαι τὴν ἶριν, ὅπου μάλιστα κρατεῖται ὁ ἥλιος πλείστη γὰρ ἐν αὐτῇ ἰκμὰς ἐνέμεινεν.	If, then, a circle be described with I as pole at the distance MI it will touch all the angles which the lines from H and K make by their reflection. If not, it can be shown, as before, that lines drawn to different points in the semicircle will have the same ratio to one another, which was impossible. If, then, the semicircle A be revolved about the diameter HKI, the lines reflected from the points H, K at the point M will have the same ratio, and will make the angle KMH equal, in every plane. Further, the angle which HM and MI make with HI will always be the same. So there are a number of triangles on HI and KI equal to the triangles HMI and KMI. Their perpendiculars will fall on HI at the same point and will be equal. Let O be the point on which they fall. Then O is the centre of the circle, half of which, MN, is cut off by the horizon.
πάλιν ἔστω ὁρίζων μὲν ἐφ' οὗ τὸ ΑΚΓ, ἐπανατεταλκέτω δὲ τὸ Η, ὁ δ' ἄξων ἔστω νῦν ἐφ' οὗ τὸ ΗΠ. τὰ μὲν οὖν ἄλλα πάντα ὁμοίως δειχθήσεται ὡς καὶ πρότερον, ὁ δὲ πόλος τοῦ κύκλου ὁ ἐφ' ᾧ Π κάτω ἔσται τοῦ ὁρίζοντος τοῦ ἐφ' ᾧ τὸ ΑΓ, (377a.) ἀρθέντος τοῦ ἐφ' ᾧ τὸ Η σημείου. ἐπὶ δὲ τῆς αὐτῆς ὅ τε πόλος καὶ τὸ κέντρον τοῦ κύκλου καὶ τὸ τοῦ ὁρίζοντος νῦν τὴν ἀνατολήν ἔστι γὰρ οὗτος ἐφ' ᾧ τὸ ΗΠ. ἐπεὶ δὲ τῆς διαμέτρου τῆς ΑΓ τὸ ΚΗ ἐπάνω, τὸ κέντρον εἴη ἂν ὑποκάτω τοῦ ὁρίζοντος πρότερον τοῦ ἐφ' ᾧ τὸ ΑΓ, ἐπὶ τῆς ΚΠ γραμμῆς, ἐφ' οὗ τὸ Β. ὥστ' ἔλαττον ἔσται τὸ ἐπάνω τμῆμα ἡμικυκλίου τὸ ἐφ' ᾧ Ψ Υ τὸ γὰρ ΨΥΟ ἡμικύκλιον ἦν, νῦν δὲ ἀποτέτμηται ἀπὸ τοῦ ΑΓ ὁρίζοντος. τὸ δὴ ΟΥ ἀφανὲς ἔσται αὐτοῦ, ἐπαρθέντος τοῦ ἡλίου ἐλάχιστον δ', ὅταν ἐπὶ μεσημβρίας ὅσον γὰρ ἀνώτερον τὸ Η, κατώτερον ὅ τε πόλος καὶ τὸ κέντρον τοῦ κύκλου ἔσται. ὅτι δ' ἐν μὲν ταῖς ἐλάττοσιν ἡμέραις ταῖς μετ' ἰσημερίαν τὴν μετοπωρινὴν ἐνδέχεται ἀεὶ γίγνεσθαι ἶριν, ἐν δὲ ταῖς μακροτέραις ἡμέραις ταῖς ἀπὸ ἰσημερίας τῆς ἑτέρας ἐπὶ τὴν ἰσημερίαν τὴν ἑτέραν περὶ μεσημβρίαν οὐ γίγνεται ἶρις, αἴτιον ὅτι τὰ μὲν πρὸς ἄρκτον τμήματα πάντα μείζω ἡμικυκλίου καὶ ἀεὶ ἐπὶ μείζω ἡμικυκλίου, τὸ δ' ἀφανὲς μικρόν, τὰ δὲ πρὸς μεσημβρίαν τμήματα τοῦ ἰσημερινοῦ, τὸ μὲν ἄνω τμῆμα μικρόν, τὸ δ' ὑπὸ γῆν μέγα, καὶ ἀεὶ δὴ μείζω τὰ πορρώτερα ὥστ' ἐν μὲν ταῖς πρὸς θερινὰς τροπὰς ἡμέραις διὰ τὸ μέγεθος τοῦ τμήματος, πρὶν ἐπὶ τὸ μέσον ἐλθεῖν τοῦ τμήματος καὶ ἐπὶ τὸν μεσημβρινὸν τὴν τὸ Η, κάτω ἤδη τελέως γίγνεται ἡ τὸ Π, διὰ τὸ πόρρω ἀφεστάναι τῆς γῆς τὴν μεσημβρίαν διὰ τὸ μέγεθος τοῦ τμήματος. ἐν δὲ ταῖς πρὸς τὰς χειμερινὰςτροπὰς ἡμέραις, διὰ τὸ μὴ πολὺ ὑπὲρ γῆς εἶναι τὰ τμήματα τῶν κύκλων, τοὐναντίον ἀναγκαῖον γίγνεσθαι βραχὺ γὰρ ἀρθείσης τῆς ἐφ' ᾧ τὸ Η, ἐπὶ τῆς μεσημβρίας γίγνεται ὁ ἥλιος.	Next let the horizon be ABG but let H have risen above the horizon. Let the axis now be HI. The proof will be the same for the rest as before, but the pole I of the circle will be below the horizon Ag since the point H has risen above the horizon. But the pole, and the centre of the circle, and the centre of that circle (namely HI) which now determines the position of the sun are on the same line. But since KH lies above the diameter AG, the centre will be at O on the line KI below the plane of the circle AG determined the position of the sun before. So the segment YX which is above the horizon will be less than a semicircle. For YXM was a semicircle and it has now been cut off by the horizon AG. So part of it, YM, will be invisible when the sun has risen above the horizon, and the segment visible will be smallest when the sun is on the meridian; for the higher H is the lower the pole and the centre of the circle will be. In the shorter days after the autumn equinox there may be a rainbow at any time of the day, but in the longer days from the spring to the autumn equinox there cannot be a rainbow about midday. The reason for this is that when the sun is north of the equator the visible arcs of its course are all greater than a semicircle, and go on increasing, while the invisible arc is small, but when the sun is south of the equator the visible arc is small and the invisible arc great, and the farther the sun moves south of the equator the greater is the invisible arc. Consequently, in the days near the summer solstice, the size of the visible arc is such that before the point H reaches the middle of that arc, that is its point of culmination, the point is well below the horizon; the reason for this being the great size of the visible arc, and the consequent distance of the point of culmination from the earth. But in the days near the winter solstice the visible arcs are small, and the contrary is necessarily the case: for the sun is on the meridian before the point H has risen far.

Postquam philosophus determinavit de causa generationis iridis et de coloribus eius, determinat consequenter de figura eius, et de his quae consequuntur ipsam quantum ad figuram. Et circa hoc primo praemittit intentionem suam, et dicit quod ex figurali descriptione iridis, quantum ad situm eius et solis et visus, potest esse manifestum considerantibus, quod iris non potest apparere secundum circulum perfectum, neque secundum proportionem maiorem semicirculo; et etiam manifestum erit de aliis accidentibus circa ipsam.

Secundo ibi: hemisphaerio enim existente etc., prosequitur propositum suum. Et circa hoc sciendum est, quod Aristoteles intendit probare unam conclusionem quadrimembrem: scilicet quod iris non est maior semicirculo; sed quando astrum refractum est in oriente vel occidente, tunc figura iridis est semicirculi completi; quando autem supra horizontem elevatum, tunc iris apparet nobis minoris figurae quam semicirculus; quando vero astrum est in meridie, tunc apparet minimae figurae quam possit apparere. Quam conclusionem ipse probat multis suppositionibus ac propositionibus mathematicalibus praemissis, quas si clare deducere vellem, oporteret multum digredi a physico proposito, et ideo videantur in littera. Ratio autem physica huius est, quia astrum quodlibet naturaliter emittit radios suos in directum, quoadusque non invenit corpus opacum prohibens processum radiorum in directum: unde etiam tales radii quoadusque non reflectuntur, dicuntur radii recti, quasi in rectum tendentes. Ex quo patet ratio illius quod supra dictum est, quod iris fit ex opposito astri: quia illud agit in partem sibi diametraliter oppositam, et ab ea reflectitur. Astrum autem in nube opposita causat quidem figuram circularem, nisi impediatur: quia omne agens intendit per suam actionem inducere similitudinem suam in passum; sed apparet nobis tantum semicirculus, quia reliqua pars nubis vel rorationis in qua fit iris, occultatur sub horizonte. Cum igitur astrum est in oriente, nubes ei opposita est in occidente, dimidia sub horizonte et dimidia supra, et ex consequenti apparet nobis tantum semicirculus refractionis irialis: quia reliqua dimidia pars rorationis occultatur sub horizonte, ut dictum est. Quanto autem magis elevatur astrum super horizontem, tanto magis pars ei opposita in qua fit iris, occultatur sub ea; et ideo minor pars circuli refractionis apparet nobis: quia roratio opposita astro magis occultatur. Quando autem astrum est elevatissimum, et est in meridie, tunc minima portio circuli irialis apparet: quia roratio opposita astro in qua fit iris, maxime occultatur. Nunquam igitur apparet maior portio quam semicirculus, et saepe apparet minor.

Quod autem in minoribus et cetera. Postquam determinavit de figura iridis, hic determinat de quibusdam aliis accidentibus. Et dicit quod colores iridis apparent fortiores in extremitatibus iridis circa terram quam in medio, eo quod in corpore densiori lumen fortius retinetur et fortificatur magis: nubes autem est densior in extremitatibus quam in medio. Secundum accidens est, quod iris raro fit a luna: quod probat dupliciter. Primo, quia nunquam fit a luna nisi in plenilunio, propter debilitatem sui luminis in aliis temporibus. Secundo, quia luna propter debilitatem sui luminis non sufficit elevare tantos vapores, quod super eos possit causari iris. Tertium accidens, quod accidit propter eandem causam, scilicet propter elevationem vaporum, est quod in ea parte hemisphaerii maxime fit iris, in qua sol elevat maiores vapores: quia ex eis generatur nubes sub qua debet fieri iris. Quartum vero est, quia in diebus brevioribus post aequinoctium autumnale, quando dies sunt minores noctibus, iris apparere potest omni hora diei; sed post aequinoctium vernale, quando dies sunt maiores noctibus, iris non potest apparere omni hora: quia non apparet circa meridiem his quibus solstitium multum elevatur in meridie. Et huius ratio est, quia portiones circuli quas sol describit in diebus longioribus super horizontem, sunt minores semicirculo, sed portiones quas describit quando accedit ad tropicum hiemalem, sunt maiores: quia quanto plus sol elevatur supra horizontem vel supra terram, tanto depressior est polus et arcus iridis in parte ei opposita sub terra, sicut dictum est; magis autem elevatur sol in vere et in aestate quam in autumno et hieme: et ex hoc etiam maiores causat calores, et arcus iridis causatus ab eo in parte opposita, est magis depressus, intantum ut propter parvitatem non appareat, quia quod est parvum, videtur immanifestum. Portio autem circuli iridis in diebus longioribus est parva: in diebus autem brevioribus, quia sol non multum elevatur a terra, ideo decisio circuli iridis non multum deprimitur, et maior pars remanet super terram, et ex consequenti iris tunc magis apparet. Ex quo corollarie concludi potest, quod defectus integri circuli in iride non est ex parte radii luminosi incidentis, sed est ideo, quia nubes vel roratio in qua fit iris, occultatur secundum partem sub horizonte.

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Lectio 8

6	6
τὰς δ' αὐτὰς αἰτίας ὑποληπτέον καὶ περὶ παρηλίων καὶ ῥάβδων ταῖς εἰρημέναις. γίγνεται γὰρ παρήλιος μὲν ἀνακλωμένης τῆς ὄψεως πρὸς τὸν ἥλιον, ῥάβδοι δὲ διὰ τὸ προσπίπτειν τοιαύτην οὖσαν τὴν ὄψιν, οἵαν εἴπομεν ἀεὶ γίγνεσθαι ὅταν πλησίον ὄντων τοῦ ἡλίου νεφῶν ἀπό τινος ἀνακλασθῇ τῶν ὑγρῶν πρὸς τὸ νέφος φαίνεται γὰρ αὐτὰ μὲν (377b.) ἀχρωμάτιστα τὰ νέφη κατ' εὐθυωρίαν εἰσβλέπουσιν, ἐν δὲ τῷ ὕδατι ῥάβδων μεστὸν τὸ νέφος πλὴν τότε μὲν ἐν τῷ ὕδατι δοκεῖ τὸ χρῶμα τοῦ νέφους εἶναι, ἐν δὲ ταῖς ῥάβδοις ἐπ' αὐτοῦ τοῦ νέφους. γίγνεται δὲ τοῦτο ὅταν ἀνώμαλος ἡ τοῦ νέφους ᾖ σύστασις, καὶ τῇ μὲν πυκνότερον τῇ δὲ μανόν, καὶ τῇ μὲν ὑδατωδέστερον τῇ δ' ἧττον ἀνακλασθείσης γὰρ τῆς ὄψεως πρὸς τὸν ἥλιον, τὸ σχῆμα μὲν [τοῦ ἡλίου] οὐχ ὁρᾶται [διὰ μικρότητα τῶν ἐνόπτρων], τὸ δὲ χρῶμα διὰ δὲ τὸ ἐν ἀνωμάλῳ φαίνεσθαι λαμπρὸν καὶ λευκὸν τὸν ἥλιον, πρὸς ὃν ἀνεκλάσθη ἡ ὄψις, τὸ μὲν φοινικοῦν φαίνεται, τὸ δὲ πράσινον ἢ ξανθόν. διαφέρει γὰρ οὐδὲν διὰ τοιούτων ὁρᾶν ἢ ἀπὸ τοιούτων ἀνακλωμένην ἀμφοτέρως γὰρ φαίνεται τὴν χρόαν ὅμοιον, ὥστ' εἰ κἀκείνως φοινικοῦν, καὶ οὕτως.	Mock suns, and rods too, are due to the causes we have described. A mock sun is caused by the reflection of sight to the sun. Rods are seen when sight reaches the sun under circumstances like those which we described, when there are clouds near the sun and sight is reflected from some liquid surface to the cloud. Here the clouds themselves are colourless when you look at them directly, but in the water they are full of rods. The only difference is that in this latter case the colour of the cloud seems to reside in the water, but in the case of rods on the cloud itself. Rods appear when the composition of the cloud is uneven, dense in part and in part rare, and more and less watery in different parts. Then the sight is reflected to the sun: the mirrors are too small for the shape of the sun to appear, but, the bright white light of the sun, to which the sight is reflected, being seen on the uneven mirror, its colour appears partly red, partly green or yellow. It makes no difference whether sight passes through or is reflected from a medium of that kind; the colour is the same in both cases; if it is red in the first case it must be the same in the other.
αἱ μὲν οὖν ῥάβδοι γίγνονται δι' ἀνωμαλίαν τοῦ ἐνόπτρου οὐ τῷ σχήματι ἀλλὰ τῷ χρώματι ὁ δὲ παρήλιος, ὅταν ὅτι μάλιστα ὁμαλὸς ᾖ ὁ ἀὴρ καὶ πυκνὸς ὁμοίως διὸ φαίνεται λευκός. ἡ μὲν γὰρ ὁμαλότης τοῦ ἐνόπτρου ποιεῖ χρόαν μίαν τῆς ἐμφάσεως ἡ δ' ἀνάκλασις ἀθρόας τῆς ὄψεως, διὰ τὸ ἅμα προσπίπτειν πρὸς τὸν ἥλιον ἀπὸ πυκνῆς οὔσης τῆς ἀχλύος, καὶ οὔπω μὲν οὔσης ὕδωρ ἐγγὺς δ' ὕδατος, [διὰ] τὸ ὑπάρχον τῷ ἡλίῳ ἐμφαίνεσθαι χρῶμα ποιεῖ, ὥσπερ ἀπὸ χαλκοῦ λείου κλωμένην διὰ τὴν πυκνότητα. ὥστ' ἐπεὶ τὸ χρῶμα τοῦ ἡλίου λευκόν, καὶ ὁ παρήλιος φαίνεται λευκός. διὰ δὲ τὸ αὐτὸ τοῦτο μᾶλλον ὕδατος σημεῖον ὁ παρήλιος τῶν ῥάβδων μᾶλλον γὰρ συμβαίνει τὸν ἀέρα εὐεργῶς ἔχειν πρὸς γένεσιν ὕδατος. ὁ δὲ νότιος τοῦ βορείου μᾶλλον, ὅτι μᾶλλον ὁ νότιος ἀὴρ εἰς ὕδωρ μεταβάλλει τοῦ πρὸς ἄρκτον.	Rods then are occasioned by the unevenness of the mirror—as regards colour, not form. The mock sun, on the contrary, appears when the air is very uniform, and of the same density throughout. This is why it is white: the uniform character of the mirror gives the reflection in it a single colour, while the fact that the sight is reflected in a body and is thrown on the sun all together by the mist, which is dense and watery though not yet quite water, causes the sun's true colour to appear just as it does when the reflection is from the dense, smooth surface of copper. So the sun's colour being white, the mock sun is white too. This, too, is the reason why the mock sun is a surer sign of rain than the rods; it indicates, more than they do, that the air is ripe for the production of water. Further a mock sun to the south is a surer sign of rain than one to the north, for the air in the south is readier to turn into water than that in the north.
γίγνονται δ', ὥσπερ εἴπομεν, περί τε δυσμὰς καὶ περὶ τὰς ἀνατολάς, καὶ οὔτε ἄνωθεν οὔτε κάτωθεν, ἀλλ' ἐκ τῶν πλαγίων καὶ ῥάβδοι καὶ παρήλιοι καὶ οὔτ' ἐγγὺς τοῦ ἡλίου λίαν οὔτε πόρρω παντελῶς ἐγγὺς μὲν γὰρ οὖσαν ὁ ἥλιος διαλύει τὴν σύστασιν, πόρρω δ' οὔσης ἡ ὄψις οὐκ ἀνακλασθήσεται ἀπὸ γὰρ μικροῦ ἐνόπτρου πόρρω ἀποτεινομένη ἀσθενὴς γίγνεται διὸ καὶ αἱ ἅλως οὐ γίγνονται ἐξ ἐναντίας τοῦ ἡλίου. ἄνω (378a.) μὲν οὖν ἐὰν γίγνηται καὶ ἐγγύς, διαλύσει ὁ ἥλιος ἐὰν δὲ πόρρω, ἐλάττων ἡ ὄψις οὖσα ἢ ὥστε ποιεῖν ἀνάκλασιν οὐ προσπεσεῖται. ἐν δὲ τῷ πλαγίῳ [ὑπὸ τὸν ἥλιον] ἐστὶ τοσοῦτον ἀποστῆναι τὸ ἔνοπτρον, ὥστε μήτε τὸν ἥλιον διαλῦσαι, τήν τε ὄψιν ἀθρόαν ἐλθεῖν, διὰ τὸ πρὸς τὴν γῆν φερομένην μὴ διασπᾶσθαι ὥσπερ δι' ἀχανοῦς φερομένην. ὑπὸ δὲ τὸν ἥλιον οὐ γίγνεται διὰ τὸ πλησίον μὲν τῆς γῆς διαλύεσθαι ἂν ὑπὸ τοῦ ἡλίου, ἄνω δὲ μεσουρανίου <�γιγνομένης συστάσεως> τὴν ὄψιν διασπᾶσθαι. καὶ ὅλως οὐδ' ἐκ πλαγίου μεσουρανίου γίγνεται ἡ γὰρ ὄψις οὐχ ὑπὸ τὴν γῆν φέρεται, ὥστε ὀλίγη ἀφικνεῖται πρὸς τὸ ἔνοπτρον, καὶ ἡ ἀνακλωμένη γίγνεται πάμπαν ἀσθενής.	Mock suns and rods are found, as we stated, about sunset and sunrise, not above the sun nor below it, but beside it. They are not found very close to the sun, nor very far from it, for the sun dissolves the cloud if it is near, but if it is far off the reflection cannot take place, since sight weakens when it is reflected from a small mirror to a very distant object. (This is why a halo is never found opposite to the sun.) If the cloud is above the sun and close to it the sun will dissolve it; if it is above the sun but at a distance the sight is too weak for the reflection to take place, and so it will not reach the sun. But at the side of the sun, it is possible for the mirror to be at such an interval that the sun does not dissolve the cloud, and yet sight reaches it undiminished because it moves close to the earth and is not dissipated in the immensity of space. It cannot subsist below the sun because close to the earth the sun's rays would dissolve it, but if it were high up and the sun in the middle of the heavens, sight would be dissipated. Indeed, even by the side of the sun, it is not found when the sun is in the middle of the sky, for then the line of vision is not close to the earth, and so but little sight reaches the mirror and the reflection from it is altogether feeble.
ὅσα μὲν οὖν ἔργα συμβαίνει παρέχεσθαι τὴν ἔκκρισιν ἐν τοῖς τόποις τοῖς ὑπὲρ τῆς γῆς, σχεδόν ἐστι τοσαῦτα καὶ τοιαῦτα.	Some account has now been given of the effects of the secretion above the surface of the earth;

Postquam philosophus determinavit de halo et iride, nunc consequenter determinat de virgis et pareliis. Et circa hoc duo facit: primo determinat de generatione virgarum et pareliorum; secundo de accidentibus circa ea, ibi: fiunt autem sicut diximus et cetera. Circa primum iterum duo facit: primo ostendit modum et causam generationis virgarum et pareliorum in communi; secundo ostendit eam in speciali de utroque eorum, ibi: virgae autem propterea et cetera. Dicit ergo primo, quod existimandum est quod parelii et virgae fiant propter easdem causas sicut halo et iris, quia omnia haec sunt refractio quaedam, licet differant secundum diversam dispositionem et situm caliginis a qua fit refractio: quia parelius generatur ex refractione visus a nube aliqua ad solem, et virgae similiter. Et iterum utitur hic philosophus opinione mathematicorum sui temporis, qui dicebant visum refrangi ab obiecto ad solem: sed tamen secundum veritatem lumen refrangitur ab obiecto ad visum.

Deinde cum dicit: virgae autem propterea etc., assignat causam et modum generationis ipsorum. Et circa hoc duo facit: primo ostendit causam generationis virgarum; secundo generationis pareliorum, ibi: parelius et cetera. Prima iterum in duas: in prima comparat virgas ad ea quae apparent ex refractione in aliis; secundo declarat modum generationis virgarum, ibi: fit autem hoc cum irregularis et cetera. Dicit ergo primo quod virgae generantur propterea, quod visus qui refrangitur ex nube in latere solis existente, est talis secundum effectum, qualis est quando refrangitur ab aqua vel ab aliquo alio humidorum ad nubem visam, sicut diximus prius. Nam nubes prope solem existentes, visae secundum rectum aspectum, non videntur coloratae diversis coloribus apparentibus et propriis, ut frequenter, sed quando aspiciuntur per refractionem ab aqua vel ab aliquo humidorum, tunc apparent coloratae vel virgulatae ad modum virgularum. Et tamen in hoc est differentia: quia in aliis apparentiis illa diversitas coloris nubis apparet in ipsa nube, sed in virgis apparet quodammodo supra ipsam. Et huius ratio est, quia albo et nigro apparentibus in eadem superficie, nigrum videtur longius, sicut e converso remotius visum apparet nigrum, eo quod minus alterat: sed colores virgarum sunt nigri vel propinquiores nigro, et sunt in eadem superficie cum fulgido nubis, et per consequens apparent remotiores quam fulgidum nubis.

Deinde cum dicit: fit autem hoc etc., assignat modum generationis virgarum in speciali. Et dicit quod generatio virgarum fit a nube, quando nubes a qua fit refractio est irregularis: scilicet non unius dispositionis per totum, sed in una parte rarior, in alia densior, et in una propinquior aquae, in alia remotior. Radii ergo incidentes super partes rariores, transeunt per illas tanquam per foramina, et colorantur reflexis radiis super parte aquosa et rorida, in qua apparet color sine figura. Et propter irregularitatem illius nubis ad quam refranguntur radii solares albi et clari, apparent diversi colores virgarum: scilicet puniceus in parte clariori nubis et magis propinqua ad album, viridis autem in parte magis densa, et per consequens etiam magis nigra, xanthos vero apparet vel per iuxtapositionem duorum praedictorum, sicut dictum est supra, vel etiam apparet in parte proportionaliter densa. Licet autem in generatione virgarum lumen aliquo modo transeat per partes nubis, tamen fiunt diversi colores in virgis, sicut in iride, in qua lumen immediate refrangitur a nube rorida: quia ut dicit, nihil differt quantum ad generationem colorum diversorum, videre solem per nubem transparentem aliquo modo, et videre ipsum immediate refractum a nube. Deinde quasi recapitulando dicit, quod virgae generantur propter irregularitatem speculi, idest nubis roridae, non secundum figuram, idest non repraesentando figuram obiecti, sed colorem: quia scilicet nubes non est nata facere unum colorem.

Deinde cum dicit: parelius autem etc., ostendit modum generationis pareliorum. Et dicit quod parelii fiunt, quando aer, idest nubes subtilis a qua fit refractio, est maxime regularis, uniformis et spissa, et lumen solis fortiter refrangitur a tali nube: tunc apparet ibi color albus ad similitudinem coloris solis, quasi alter sol; quia regularitas speculi facit colorem apparentem esse unum et regularem, sicut diversa dispositio partium nubis facit colores esse diversos. Hoc autem declarat per exemplum: sicut enim lumen quod refrangitur ab aere polito sive ferro, puta ab armis militum, est coloris clari et albi, et est fulgidum, sic lumen quod refrangitur a nube, vel caligine spissa et existente propinqua ad hoc quod convertatur in aquam, nondum tamen in eam conversa (quae dicitur nubes rorida), est album et clarum. Ex isto concludit duo corollaria. Primum, quod parelius est magis signum pluviae quam virgae, quia generatur per refractionem a nube regulari et spissa, quae est propinqua ad dispositionem aquae: et ideo citius ex ea generatur aqua. Secundum est, quod parelius Australis, idest qui apparet quando flant venti Australes, vel etiam qui apparet ex parte Australi, est magis signum pluviae quam borealis: quia ventus Australis propter calidum temperatum elevat multos vapores, et congregat eos in nubes, et etiam nubes permutat in aquas, sed Boreas propter frigiditatem et siccitatem propellit nubes et prohibet elevationem vaporum, sicut superius dictum est.

Deinde cum dicit: fiunt autem sicut diximus etc., assignat philosophus causam accidentium circa virgas et parelios. Et pro primo dicit, quod virgae et parelii maxime accidunt circa occasum et ortum solis; cuius ratio est, quia tunc nubes non disperguntur calore solis ita de facili, cum calor solis non sit multum vehemens. Secundum accidens est, quod non fiunt supra solem, neque desubtus. Et ratio est, quia si fierent supra solem, non viderentur propter distantiam (licet impossibile sit, quod ibi fiant, cum supra solem non fiant nubes vel roratio); et si sub sole fierent, dissolverentur propter radios directe incidentes sub sole: et etiam radii solares non venirent ad nos, sed propter reflexionem potius reverterentur ad caelum. Tertium est, quod fiunt a latere solis, puta nube existente ex parte meridiei vel Boreae: quia quando nubes stant a latere, tunc sol non dissolvit eas, si sint in debita distantia a sole, et tunc visus potest ad illas pertingere propter convenientem proportionem distantiae. Quartum est, quod non fiunt multum prope solem, nec etiam multum longe. Et huius ratio est, quia prope solem sol dissolvit consistentiam nubis sua caliditate; de longe autem non videretur: quia a parvo speculo fit debilis refractio, ut patet, nubes autem remota a sole, ubi sol habet paucam virtutem elevandi vapores a terra, est parva, et ex consequenti non videretur in ea refractio. Non fiunt etiam ut in pluribus sole existente in meridie: quia tunc nubes sursum elevata prope solem, est multum remota a visu, et propter hoc color nubis non fertur ad eum in superficie terrae, sed movetur per aerem supra terram et prope solem, et ibi propter excellentem fulgorem dispergitur: et ex hoc non facit virgas et parelios. Finaliter recapitulat dicta in praecedentibus, dicens quod omnia opera, quae generantur in locis supra terram per motum et alterationem, et etiam in terra ex segregatione humida et sicca, fere sunt tot et talia. Dicit autem fere, propter quaedam accidentia quorum causas non dixit expresse, quae tamen ex praedictis reddi possunt: sicut sunt quidam ignes qui videntur volitare in superficie terrae, et lapides et alia quaedam cadentia ex nubibus, et coloratio aquae descendentis, puta quando pluit aqua sanguinea.

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Lectio 9

ὅσα δ' ἐν αὐτῇ τῇ γῇ, ἐγκατακλειομένη τοῖς τῆς γῆς μέρεσιν, ἀπεργάζεται, λεκτέον. ποιεῖ γὰρ δύο διαφορὰς σωμάτων διὰ τὸ διπλῆ πεφυκέναι καὶ αὐτή, καθάπερ καὶ ἐν τῷ μετεώρῳ δύο μὲν γὰρ αἱ ἀναθυμιάσεις, ἡ μὲν ἀτμιδώδης ἡ δὲ καπνώδης, ὥς φαμεν, εἰσίν δύο δὲ καὶ τὰ εἴδη τῶν ἐν τῇ γῇ γιγνομένων, τὰ μὲν ὀρυκτὰ τὰ δὲ μεταλλευτά. ἡ μὲν οὖν ξηρὰ ἀναθυμίασίς ἐστιν ἥ τις ἐκπυροῦσα ποιεῖ τὰ ὀρυκτὰ πάντα, οἷον λίθων τε γένη τὰ ἄτηκτα καὶ σανδαράκην καὶ ὤχραν καὶ μίλτον καὶ θεῖον καὶ τἆλλα τὰ τοιαῦτα. τὰ δὲ πλεῖστα τῶν ὀρυκτῶν ἐστιν τὰ μὲν κονία κεχρωματισμένη, τὰ δὲ λίθος ἐκ τοιαύτης γεγονὼς συστάσεως, οἷον τὸ κιννάβαρι. τῆς δ' ἀναθυμιάσεως τῆς ἀτμιδώδους, ὅσα μεταλλεύεται, καὶ ἔστιν ἢ χυτὰ ἢ ἐλατά, οἷον σίδηρος, χρυσός, χαλκός. ποιεῖ δὲ ταῦτα πάντα ἡ ἀναθυμίασις ἡ ἀτμιδώδης ἐγκατακλειομένη, καὶ μάλιστα ἐν τοῖς λίθοις, διὰ ξηρότητα εἰς ἓν συνθλιβομένη καὶ πηγνυμένη, οἷον ἢ δρόσος ἢ πάχνη, ὅταν ἀποκριθῇ. ἐνταῦθα δὲ πρὶν ἀποκριθῆναι γεννᾶται ταῦτα. διὸ ἔστι μὲν ὡς ὕδωρ ταῦτα, ἔστιν δ' ὡς οὔ δυνάμει μὲν γὰρ ἡ ὕλη ὕδατος ἦν, ἔστι δ' οὐκέτι, οὐδ' ἐξ ὕδατος γενομένου διά τι πάθος, ὥσπερ (378b.) οἱ χυμοί οὐδὲ γὰρ οὕτω γίγνεται τὸ μὲν χαλκὸς τὸ δὲ χρυσός, ἀλλὰ πρὶν γενέσθαι παγείσης τῆς ἀναθυμιάσεως ἕκαστα τούτων ἐστίν. διὸ καὶ πυροῦται πάντα καὶ γῆν ἔχει ξηρὰν γὰρ ἔχει ἀναθυμίασιν ὁ δὲ χρυσὸς μόνος οὐ πυροῦται.

we must go on to describe its operations below, when it is shut up in the parts of the earth. Just as its twofold nature gives rise to various effects in the upper region, so here it causes two varieties of bodies. We maintain that there are two exhalations, one vaporous the other smoky, and there correspond two kinds of bodies that originate in the earth, 'fossiles' and metals. The heat of the dry exhalation is the cause of all 'fossiles'. Such are the kinds of stones that cannot be melted, and realgar, and ochre, and ruddle, and sulphur, and the other things of that kind, most 'fossiles' being either coloured lye or, like cinnabar, a stone compounded of it. The vaporous exhalation is the cause of all metals, those bodies which are either fusible or malleable such as iron, copper, gold. All these originate from the imprisonment of the vaporous exhalation in the earth, and especially in stones. Their dryness compresses it, and it congeals just as dew or hoar-frost does when it has been separated off, though in the present case the metals are generated before that segregation occurs. Hence, they are water in a sense, and in a sense not. Their matter was that which might have become water, but it can no longer do so: nor are they, like savours, due to a qualitative change in actual water. Copper and gold are not formed like that, but in every case the evaporation congealed before water was formed. Hence, they all (except gold) are affected by fire, and they possess an admixture of earth; for they still contain the dry exhalation.

κοινῇ μὲν οὖν εἴρηται περὶ αὐτῶν ἁπάντων, ἰδίᾳ δὲ σκεπτέον προχειριζομένοις περὶ ἕκαστον γένος.

This is the general theory of all these bodies, but we must take up each kind of them and discuss it separately.

Postquam philosophus in superioribus determinavit de his quae generantur ex exhalatione humida et sicca per motum et alterationem, aut etiam per refractionem luminis supra terram, et etiam de aliis quae causantur per motum ab exhalatione sicca in ipsa terra, scilicet de agitatione et motu terrae, hic determinare intendit breviter de his, quae generantur in profundo ipsius terrae principaliter per alterationem. Et circa hoc duo facit. Primo praemittit distinctionem eorum quae fiunt in ipsa terra, et dicit quod sicut in alto, idest supra terram, est duplex exhalatio, una vaporosa, idest humida, ex qua generantur ea quae generantur per ingrossationem a frigido, alia autem fumosa et sicca, ex qua fiunt ea quae generantur per subtiliationem vel inflammationem, ita similiter in partibus terrae est duplex exhalatio, ex qua generantur duo genera corporum, quorum quaedam dicuntur fossibilia, eo quod fodiuntur in terra, et sunt similia terrae defossae: et generantur ex sicca exhalatione; alia vero dicuntur metallica, quae magis generantur per coagulationem.

Secundo ibi: sicca quidem etc., assignat causam praedictorum. Et primo assignat causam fossibilium, et dicit quod exhalatio sicca a dominio, secundum quod est ignita a calido, est principium omnium fossibilium: ita quod exhalatio sit materia ex qua fiunt. Sed calidum igniens, secundum quod commensuratur frigido a virtute caelesti, mediante continuitate, est quodammodo principium activum; ita quod principium activum principale est virtus caelestis, quae dicitur virtus mineralis: a qua habent fossibilia quaedam, puta lapides pretiosi, quandam virtutem caelestem et occultam, per quam occultas operationes vere exercent; principium autem instrumentale est caliditas, quae humidum desiccat, et generat omnia fossibilia. Huiusmodi autem fossibilia sunt genera lapidum non liquabilium: quod dicit ad differentiam quorundam fossibilium quae sunt liquabilia, ut vernix, oricella et sulphur, et alia huiusmodi; quae omnia generantur a calido exsiccante exhalationem et consumente humidum et aliqualiter colorante. Et horum fossibilium quaedam fiunt sicut pulvis coloratus: sicut illa quae generantur a calido fortiter consumente humidum et aliqualiter adurente, ut sunt omnia supradicta; alia autem sunt quasi lapides aggregati per condensationem ex pluribus partibus, et generantur ex eadem exhalatione a calido exhalante humidum superfluum, et fortiter terminante humidum cum sicco.

Secundo ibi: exhalationis autem etc., determinat de his quae fiunt ab exhalatione humida. Et circa hoc duo facit: primo assignat causam generationis eorum; secundo ostendit modum et locum generationis eorum, ibi: facit autem et cetera. Dicit ergo primo, quod illa quae metallantur, idest habent formam metalli, generantur materialiter ex vaporosa exhalatione, et a frigido commensurato coagulante effective instrumentaliter: principale autem agens est virtus caelestis mineralis, sicut supra diximus. Et istorum quaedam sunt fusibilia, et quaedam ductibilia: fusibilia seu liquabilia sunt, quae plus accedunt ad naturam humidi quam sicci, sicut stannum aut plumbum; sed ductibilia sunt, quae habent humidum magis reductum ad medium per siccum, ut sunt ea in quibus est bona terminatio sicci et humidi, sicut in auro etc., aut in quibus est humidum viscosum non bene separabile a sicco, sicut ferrum, quod calefactum ictu mallei extenditur. Sciendum est autem, quod corpora quae hic dicuntur fusibilia, seu liquabilia, non ita sunt fusibilia, quod non sint etiam ductibilia, quamvis in hoc loco contra ductibilia distinguantur: sed ideo dicuntur esse liquabilia, quia melius et facilius liquantur quam ducantur, et ductibilia e converso dicuntur, quae facilius ducuntur, quamvis etiam liquari et fundi possint, ut ferrum et aes.

Deinde cum dicit: facit autem haec etc., assignat modum et locum generationis praedictorum. Et dicit quod huiusmodi generantur ex exhalatione vaporosa inclusa in partibus terrae, et praecipue in lapidibus, propter siccitatem lapidum bene coarctantem humidum vaporosae exhalationis, et propter fortiorem et maiorem coagulationem factam a frigido commensurato formae metalli virtute caelesti, quae dicitur virtus mineralis, ut supra dictum est: sicut ab eodem frigido generantur supra terram ros et pruina, quando a vapore segregata est exhalatio calida et sicca, quae sursum movebat. Est tamen differentia in generatione istorum, quia in generatione roris et pruinae prius segregatur siccitas, antequam materia coaguletur et ros descendat: et ex hoc ros et pruina sunt liquida; sed metalla generantur in partibus terrae ex eadem exhalatione, antequam separetur siccitas: et ideo sunt dura, et quanto plus est in eis de siccitate, tanto sunt magis dura. Et propter hoc verum est dicere, quod metalla sunt aqua secundum unum modum, quia scilicet fiunt ex vapore humido a dominio, qui est in potentia aqua, et est materia aquae: et secundum alium modum non sunt aqua, quia scilicet siccitas in eis non est segregata. In cuius signum metalla igniuntur, comburuntur et reducuntur in pulverem et terram: et hoc convenit eis solum propter siccam exhalationem, quae sola exuritur, quia est materia apta ignitioni propter siccitatem. Et ipsa etiam post exustionem reducuntur in minorem quantitatem, propter separationem alicuius grossi et impuri per exhalationem vel evaporationem humidi grossi, quae fit a calido exurente: unde etiam post exustionem vel liquationem metalla sunt duriora, quia tunc humidum metalli est magis separatum. Aurum autem solum non fit minus nec minoris ponderis quando exuritur, quia est genitum ex sicco et humido subtilissimis, et non habentibus aliquid impurum admixtum quod per ignitionem separari possit. Ipsum etiam de difficili solvitur et liquatur, licet reducatur in partes minimas, quia in ipso est optime commixtum siccum cum humido: et ideo propter fortem commixtionem de difficili separantur. Unde ex his patet, quod aurum non solum secundum opinionem hominum, sed secundum naturam rerum est nobilius et purius quam cetera metalla. Quod etiam patet ex virtute quam habet, in operando mirabiles et nobiliores operationes quam alia. Deinde recapitulando dicit, quod communiter et universaliter dictum est de omnibus fossibilibus et metallicis, quomodo generentur et quae sit eorum differentia; sed si quis velit particulariter de eis intendere, et considerare circa unumquodque eorum, quae scilicet sint principia generationis et accidentia et differentiae eorum, hoc facere habebit in eo qui de metallicis inscribitur, et in aliis, circa quae Theophrastus negotiatus est secundum Alexandrum et Commentatorem. Considerandum est autem circa principia materialia metallorum, quod sunt in duplici differentia: quaedam enim sunt materia remota talium metallicorum, sicut est vapor inclusus in locis lapidosis terrae, sicut supra declaratum est; alia autem sunt materia propinqua eorum, et haec sunt sulphur et argentum vivum, sicut alchimistae dicunt: ita quod in praedictis locis lapidosis terrae per virtutem mineralem primo generatur sulphur et argentum vivum, deinde ex ipsis generantur diversa metalla, secundum diversam commixtionem eorum. Unde etiam ipsi alchimistae per veram artem alchimiae (sed tamen difficilem, propter occultas operationes virtutis caelestis quae mineralis dicitur: quae ex eo quod sunt occultae, difficulter a nobis imitari possunt per praedicta principia, vel per principiata ab ipsis) faciunt aliquando veram generationem metallorum, aliquando quidem ex sulphure et argento praedictis sine generatione exhalationis, aliquando autem faciendo exsudare praedictam exhalationem vaporosam ab aliquibus corporibus, per applicationem caliditatis proportionatae quae est agens naturale.

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Δ
Liber 4

Lectio 1

Ἐπεὶ δὲ τέτταρα αἴτια διώρισται τῶν στοιχείων, τούτων δὲ κατὰ συζυγίας καὶ τὰ στοιχεῖα τέτταρα συμβέβηκεν εἶναι, ὧν τὰ μὲν δύο ποιητικά, τὸ θερμὸν καὶ τὸ ψυχρόν, τὰ δὲ δύο παθητικά, τὸ ξηρὸν καὶ τὸ ὑγρόν ἡ δὲ πίστις τούτων ἐκ τῆς ἐπαγωγῆς φαίνεται γὰρ ἐν πᾶσιν ἡ μὲν θερμότης καὶ ψυχρότης ὁρίζουσαι καὶ συμφύουσαι καὶ μεταβάλλουσαι τά θ' ὁμογενῆ καὶ τὰ μὴ ὁμογενῆ, καὶ ὑγραίνουσαι καὶ ξηραίνουσαι καὶ σκληρύνουσαι καὶ μαλάττουσαι, τὰ δὲ ξηρὰ καὶ ὑγρὰ ὁριζόμενα καὶ τἆλλα τὰ εἰρημένα πάθη πάσχοντα αὐτά τε καθ' αὑτὰ καὶ ὅσα κοινὰ ἐξ ἀμφοῖν σώματα συνέστηκεν ἔτι δ' ἐκ τῶν λόγων δῆλον, οἷς ὁριζόμεθα τὰς φύσεις αὐτῶν τὸ μὲν γὰρ θερμὸν καὶ ψυχρὸν ὡς ποιητικὰ λέγομεν (τὸ γὰρ συγκριτικὸν ὥσπερ ποιητικόν τί ἐστι), τὸ δὲ ὑγρὸν καὶ ξηρὸν παθητικόν (τὸ γὰρ εὐόριστον καὶ δυσόριστον τῷ πάσχειν τι λέγεται τὴν φύσιν αὐτῶν) ὅτι μὲν οὖν τὰ μὲν ποιητικὰ τὰ δὲ παθητικά, φανερόν

We have explained that the qualities that constitute the elements are four, and that their combinations determine the number of the elements to be four. Two of the qualities, the hot and the cold, are active; two, the dry and the moist, passive. We can satisfy ourselves of this by looking at instances. In every case heat and cold determine, conjoin, and change things of the same kind and things of different kinds, moistening, drying, hardening, and softening them. Things dry and moist, on the other hand, both in isolation and when present together in the same body are the subjects of that determination and of the other affections enumerated. The account we give of the qualities when we define their character shows this too. Hot and cold we describe as active, for 'congregating' is essentially a species of 'being active': moist and dry are passive, for it is in virtue of its being acted upon in a certain way that a thing is said to be 'easy to determine' or 'difficult to determine'. So it is clear that some of the qualities are active and some passive.

Postquam philosophus in superioribus determinavit de particularibus transmutationibus elementorum, quibus secundum se transmutantur tam in alto quam infra terram, hic determinat de passionibus seu transmutationibus eorum, secundum quod veniunt in compositionem mixti. Et quia elementa agunt mediantibus qualitatibus activis, et patiuntur mediantibus passivis, determinat de actione primarum qualitatum activarum, et de passione passivarum in mixtis. Convenienti autem ordine iste liber sequitur tertium, quia in fine tertii determinatum est de mineralibus: haec autem scientia multum valet ad scientiam de mineralibus. Licet aliqui dicant, quod iste liber est magis continuus cum libro de generatione, quamvis inscribatur quartus liber Meteororum.

Considerandum est autem quod scientia istius libri, et similiter omnis scientia naturalis, non est ab homine despicienda: immo qui eam despicit, despicit seipsum. Et licet multi dicant quod scientia naturalis non debet appretiari, eo quod non sit utilis ad speculationem divinorum, in qua vita beatissima et felicitas hominis consistit, sicut dicit philosophus in X Ethicorum, tamen isti decipiunt seipsos, quia non solum scientia istius libri, sed etiam tota scientia naturalis, in qua non solum oportet considerare communia, sed etiam specialia et propria unicuique, deservit ad huiusmodi speculationem divinorum: quia per manifesta et naturalia tanquam per effectus in cognitionem causarum pervenimus. Propter quod philosophus in libro metaphysicae incipit a substantiis sensibilibus, et in duodecimo naturam substantiarum separatarum probat per astronomicas rationes. Et ideo quamcumque aliam scientiam addiscimus, hoc facimus ut ad cognitionem divinorum veniamus, et qui alia intentione scientias acquirit, perversus est in intentione, nisi necessitate detineatur. Neque vile est cognoscere haec particularia naturalia, quia sicut inspicere picturam turpium animalium, ut melius cognoscantur pulchra per oppositionem turpium, non est vile, item nec causas horum cognoscere, ut veniamus in cognitionem primarum causarum: immo multo minus hoc est vile, quia res multo immaterialius sunt apud intellectum quam apud sensum. Est autem utilis scientia istius libri, non solum ad cognitionem divinorum sicut dictum est, sed fere ad totam scientiam naturalem, et maxime ad scientiam de mineralibus, quae ab Aristotele composita nondum pervenit ad nos. Est etiam utilis ad medicinam: quia hic dicitur propter quid multorum, quorum quia tantum consideratur in medicina. Et propter hoc aliqui voluerunt exponere librum istum modo medicinali sine logica: sicut Galenus recitat de quodam, quod cum quaesitum esset ab eo quid esset calidum, bene respondit, et cum contrarium argueretur, statim sibi contradixit, non cognoscens suam contradictionem, propter defectum logicae. Debet igitur iste liber exponi modo naturali, non medicinali: quia secundum Avicennam medicina versatur solum circa corpus humanum ad infirmitatem removendam et sanitatem inducendam, sed illa quae in hoc libro determinantur sunt communia omnibus mixtis, sicut patet per processum. Igitur haec scientia potius applicatur ad medicinam quam e converso, quia commune applicatur ad speciale. Est insuper utilis ad scientiam alchimiae: quia tantummodo alchimistarum est transmutare metalla secundum veritatem, et non secundum sophisticationem; quod licet sit difficile et dispendiosum, sicut supra dictum est, non tamen est impossibile. Et propter hoc intentio aliquorum est, quod metalla non differunt secundum speciem, sed secundum sanum et infirmum, vocantes metallum sanum, durum, et alia, infirma: sic facile esset metalla adinvicem transmutare. Sed credo quod differunt secundum speciem, et nihilominus transmutari possent adinvicem, quia sunt naturalia et materia eorum est una. Quod autem hoc fiat per artem est difficile, non impossibile. Non tamen intelligi debet quod artifices principaliter transmutent, sed agunt quasi instrumenta, applicando propria agentia propriis passivis: quia materia propinqua omnium metallorum est argentum vivum et sulphur, sicut dictum est, quorum naturas artifices transmutare possunt conglutinando et congelando. Vel etiam alio modo evaporatio est materia praedictorum: et de hac determinatur in isto libro, et ex consequenti iste liber est utilis ad scientiam alchimiae.

Circa determinationem igitur de qualitatibus primis duo facit. Primo resumit tria superius determinata in II de generatione et III caeli: quorum primum est quod quatuor sunt causae elementorum, per quas intelligit quatuor primas qualitates, calidum et frigidum, siccum et humidum. Et non sunt causae materiales, quia quaedam sunt actionis principia: nec sunt agentes, aut fines, quia praedicantur de suis causatis; ergo relinquitur, quod erunt causae ut formales. Et dicitur notanter ut formales, non absolute formales, ad denotandum quod non sunt formae substantiales elementorum. Secundum quod resumit, est quod quatuor sunt elementa, secundum quatuor combinationes possibiles harum qualitatum, quia in simplicibus humidum non potest uniri cum sicco, nec frigidum cum calido. Et de istis elementis, sicut dicit Commentator, medicus debet credere naturali, scilicet quod sunt quatuor, et quod magnas habent commoditates et operationes in mixto: quarum aliquas medicus inquirere debet, ad conservandum contemperamentum elementorum et qualitatum praedictarum in corpore humano. Tertium est, quod istarum qualitatum duae sunt activae, scilicet calidum et frigidum, et duae passivae, scilicet siccum et humidum; hoc autem intelligi debet quantum ad victoriam unius supra alteram in corpore mixto: quia secundum se quaelibet sunt activae et quaelibet passivae, cum sint contraria adinvicem. Et hoc philosophus probat primo per inductionem in omnibus, quia in omnibus dicimus calidum et frigidum terminare, coagulare etc., siccum vero et humidum terminari et coagulari: terminare autem est agere, terminari vero est pati. Secundo probat idem ratione, scilicet per definitionem eorum, quia calidum est, quod est congregativum similium, frigidum vero est congregativum similium et dissimilium: humidum est, quod est male terminabile termino proprio, bene autem alieno, siccum vero e converso, quod est bene terminabile termino proprio, male alieno; quod autem est congregativum, est activum, quod est terminabile, est passivum.

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Lectio 2

διωρισμένων δὲ τούτων ληπτέον ἂν εἴη τὰς ἐργασίας αὐτῶν, αἷς ἐργάζονται τὰ ποιητικά, καὶ τῶν παθητικῶν τὰ εἴδη. πρῶτον μὲν οὖν καθόλου ἡ ἁπλῆ γένεσις καὶ ἡ φυσικὴ μεταβολὴ τούτων τῶν δυνάμεών ἐστιν ἔργον, καὶ ἡ ἀντικειμένη φθορὰ κατὰ φύσιν. αὗται μὲν οὖν τοῖς τε φυτοῖς ὑπάρχουσι καὶ ζῴοις καὶ τοῖς μέρεσιν αὐτῶν. ἔστι δ' ἡ ἁπλῆ καὶ ἡ φυσικὴ γένεσις μεταβολὴ ὑπὸ τούτων τῶν δυνάμεων, ὅταν ἔχωσι λόγον, ἐκ τῆς ὑποκειμένης ὕλης ἑκάστῃ φύσει αὗται δ' εἰσὶν αἱ εἰρημέναι δυνάμεις παθητικαί. (379a.) γεννῶσι δὲ τὸ θερμὸν καὶ ψυχρὸν κρατοῦντα τῆς ὕλης ὅταν δὲ μὴ κρατῇ, κατὰ μέρος μὲν μόλυνσις καὶ ἀπεψία γίγνεται. τῇ δ' ἁπλῇ γενέσει ἐναντίον μάλιστα κοινὸν σῆψις πᾶσα γὰρ ἡ κατὰ φύσιν φθορὰ εἰς τοῦθ' ὁδός ἐστιν, οἷον γῆρας καὶ αὔανσις. τέλος δὲ πάντων τῶν ἄλλων τούτων σαπρότης, ἐὰν μή τι βίᾳ φθαρῇ τῶν φύσει συνεστώτων ἔστιν γὰρ καὶ σάρκα καὶ ὀστοῦν καὶ ὁτιοῦν κατακαῦσαι, ὧν τὸ τέλος τῆς κατὰ φύσιν φθορᾶς σῆψίς ἐστιν. διὸ ὑγρὰ πρῶτον, εἶτα ξηρὰ τέλος γίγνεται τὰ σηπόμενα ἐκ τούτων γὰρ ἐγένετο, καὶ ὡρίσθη τῷ ὑγρῷ τὸ ξηρὸν ἐργαζομένων τῶν ποιητικῶν.	Next we must describe the operations of the active qualities and the forms taken by the passive. First of all, true becoming, that is, natural change, is always the work of these powers and so is the corresponding natural destruction; and this becoming and this destruction are found in plants and animals and their parts. True natural becoming is a change introduced by these powers into the matter underlying a given thing when they are in a certain ratio to that matter, which is the passive qualities we have mentioned. When the hot and the cold are masters of the matter they generate a thing: if they are not, and the failure is partial, the object is imperfectly boiled or otherwise unconcocted. But the strictest general opposite of true becoming is putrefaction. All natural destruction is on the way to it, as are, for instance, growing old or growing dry. Putrescence is the end of all these things, that is of all natural objects, except such as are destroyed by violence: you can burn, for instance, flesh, bone, or anything else, but the natural course of their destruction ends in putrefaction. Hence things that putrefy begin by being moist and end by being dry. For the moist and the dry were their matter, and the operation of the active qualities caused the dry to be determined by the moist.
γίγνεται δ' ἡ φθορὰ ὅταν κρατῇ τοῦ ὁρίζοντος τὸ ὁριζόμενον διὰ τὸ περιέχον. (οὐ μὴν ἀλλ' ἰδίως γε λέγεται σῆψις ἐπὶ τῶν κατὰ μέρος φθειρομένων, ὅταν χωρισθῇ τῆς φύσεως.) διὸ καὶ σήπεται πάντα τἆλλα πλὴν πυρός καὶ γὰρ γῆ καὶ ὕδωρ καὶ ἀὴρ σήπεται πάντα γὰρ ὕλη τῷ πυρί ἐστι ταῦτα. σῆψις δ' ἐστὶν φθορὰ τῆς ἐν ἑκάστῳ ὑγρῷ οἰκείας καὶ κατὰ φύσιν θερμότητος ὑπ' ἀλλοτρίας θερμότητος αὕτη δ' ἐστὶν ἡ τοῦ περιέχοντος. ὥστε ἐπεὶ κατ' ἔνδειαν πάσχει θερμοῦ, ἐνδεὲς δὲ ὂν τοιαύτης δυνάμεως ψυχρὸν πᾶν, ἄμφω ἂν αἴτια εἴη, καὶ κοινὸν τὸ πάθος ἡ σῆψις, ψυχρότητός τε οἰκείας καὶ θερμότητος ἀλλοτρίας.	Destruction supervenes when the determined gets the better of the determining by the help of the environment (though in a special sense the word putrefaction is applied to partial destruction, when a thing's nature is perverted). Hence everything, except fire, is liable to putrefy; for earth, water, and air putrefy, being all of them matter relatively to fire. The definition of putrefaction is: the destruction of the peculiar and natural heat in any moist subject by external heat, that is, by the heat of the environment. So since lack of heat is the ground of this affection and everything in as far as it lacks heat is cold, both heat and cold will be the causes of putrefaction, which will be due indifferently to cold in the putrefying subject or to heat in the environment.
διὰ τοῦτο γὰρ καὶ ξηρότερα γίγνεται τὰ σηπόμενα πάντα, καὶ τέλος γῆ καὶ κόπρος ἐξιόντος γὰρ τοῦ οἰκείου θερμοῦ συνεξατμίζεται τὸ κατὰ φύσιν ὑγρόν, καὶ τὸ σπῶν τὴν ὑγρότητα οὐκ ἔστιν ἐπάγει γὰρ ἕλκουσα ἡ οἰκεία θερμότης. καὶ ἐν τοῖς ψύχεσι δ' ἧττον σήπεται ἢ ἐν ταῖς ἀλέαις (ἐν μὲν γὰρ τῷ χειμῶνι ὀλίγον ἐν τῷ περιέχοντι ἀέρι καὶ ὕδατι τὸ θερμόν, ὥστ' οὐδὲν ἰσχύει, ἐν δὲ τῷ θέρει πλέον) καὶ οὔτε τὸ πεπηγός (μᾶλλον γὰρ ψυχρὸν ἢ ὁ ἀὴρ θερμόν οὔκουν κρατεῖται, τὸ δὲ κινοῦν κρατεῖ) οὔτε τὸ ζέον ἢ θερμόν (ἐλάττων γὰρ ἡ ἐν τῷ ἀέρι θερμότης τῆς ἐν τῷ πράγματι, ὥστ' οὐ κρατεῖ οὐδὲ ποιεῖ μεταβολὴν οὐδεμίαν). ὁμοίως δὲ καὶ τὸ κινούμενον καὶ ῥέον ἧττον σήπεται τοῦ ἀκινητίζοντος ἀσθενεστέρα γὰρ γίγνεται ἡ ὑπὸ τῆς ἐν τῷ ἀέρι θερμότητος κίνησις τῆς ἐν τῷ (379b.) πράγματι προϋπαρχούσης, ὥστε οὐδὲν ποιεῖ μεταβάλλειν. ἡ δ' αὐτὴ αἰτία καὶ τοῦ τὸ πολὺ ἧττον τοῦ ὀλίγου σήπεσθαι ἐν γὰρ τῷ πλέονι πλέον ἐστὶν πῦρ οἰκεῖον καὶ ψυχρὸν ἢ ὥστε κρατεῖν τὰς ἐν τῷ περιεστῶτι δυνάμεις. διὸ ἡ θάλαττα κατὰ μέρος μὲν διαιρουμένη ταχὺ σήπεται, ἅπασα δ' οὔ, καὶ τἆλλα ὕδατα ὡσαύτως. καὶ ζῷα ἐγγίγνεται τοῖς σηπομένοις διὰ τὸ τὴν ἀποκεκριμένην θερμότητα φυσικὴν οὖσαν συνιστάναι τὰ ἐκκριθέντα. τί μὲν οὖν ἐστι γένεσις καὶ τί φθορά, εἴρηται.	This explains why everything that putrefies grows drier and ends by becoming earth or dung. The subject's own heat departs and causes the natural moisture to evaporate with it, and then there is nothing left to draw in moisture, for it is a thing's peculiar heat that attracts moisture and draws it in. Again, putrefaction takes place less in cold that in hot seasons, for in winter the surrounding air and water contain but little heat and it has no power, but in summer there is more. Again, what is frozen does not putrefy, for its cold is greater that the heat of the air and so is not mastered, whereas what affects a thing does master it. Nor does that which is boiling or hot putrefy, for the heat in the air being less than that in the object does not prevail over it or set up any change. So too anything that is flowing or in motion is less apt to putrefy than a thing at rest, for the motion set up by the heat in the air is weaker than that pre-existing in the object, and so it causes no change. For the same reason a great quantity of a thing putrefies less readily than a little, for the greater quantity contains too much proper fire and cold for the corresponding qualities in the environment to get the better of. Hence, the sea putrefies quickly when broken up into parts, but not as a whole; and all other waters likewise. Animals too are generated in putrefying bodies, because the heat that has been secreted, being natural, organizes the particles secreted with it. So much for the nature of becoming and of destruction.

Secundo cum dicit: determinatis autem his etc., prosequitur propositum, determinando de operationibus sive passionibus praedictarum qualitatum. Et dividitur in tres partes: in prima determinat de actione qualitatum activarum in mixto; in secunda determinat de passione passivarum, ibi: passivorum autem etc.; in tertia determinat de homoeomeris quantum ad praedictas qualitates, ibi: quoniam autem de his et cetera. Circa primum duo facit: primo determinat de operationibus consequentibus rem in constitutione et destitutione rei; secundo de operationibus consequentibus rem iam in esse constitutam, ibi: reliquum autem et cetera. Circa primum iterum duo facit: primo determinat de simplici generatione; secundo de corruptione ei opposita, ibi: putrefactio autem et cetera. Dicit ergo primo, quod post determinata dicendum est de operibus praedictarum qualitatum, et primo de simplici generatione quae fit ab istis virtutibus, sicut declarabitur, et est in plantis et aliis naturalibus. Est ergo simplex et naturalis generatio, permutatio facta ab istis virtutibus activis, cum istae virtutes in materia subiecta habent rationem, idest proportionem, ad unamquamque naturam. Dicit autem generatio simplex et naturalis, ut excludat permutationem violentam et artificialem ab his virtutibus activis. Per permutationem tangit genus, reliquum autem totum sequens ostendit differentias ad alias permutationes: per materiam autem subiectam intelligit qualitates passivas, vel materiam affectam his qualitatibus, quae est materia generationis. Dicit ergo quod hae sunt virtutes dictae contra se invicem, idest contrariae. Cum igitur activae obtinent supra passivas, tunc sequitur generatio: quando autem passivae vincunt activas ita quod non sequatur actio activarum, tunc sequitur indigestio, quae est via ad corruptionem. Dicitur autem generatio dupliciter: primo mutatio a non esse ad esse, sicut de ea determinatur in V Physic., et hoc modo sive obtineant qualitates activae sive passivae, sequitur generatio, et una et eadem mutatio est generatio unius et corruptio alterius. Alio modo dicitur generatio, quando id quod ponitur in esse est nobilius, et e converso dicitur corruptio, quando quod ponitur in esse est ignobilius: et hoc modo loquitur hic Aristoteles de generatione; quia calidum generat aliud calidum sibi simile: cum ergo obtinent qualitates activae, quod ponitur in esse est nobilius, quia qualitates activae sunt nobiliores quam passivae. Corruptio autem opposita simplici generationi est putrefactio: quod probat duplici ratione. Primo quia illa corruptio ad quam omnia terminantur naturaliter, opponitur generationi simplici et naturali; sed ad putrefactionem terminantur omnia, ut animalia quae naturaliter senescunt, et plantae et artificialia quae veterascunt: omnia denique orta occidunt, et aucta senescunt (nisi forte talia violenter corrumpantur et comburantur, quia tunc corruptio eorum non terminatur ad senectutem vel vetustatem): senectus autem et vetustas sunt quaedam putrefactiones. Secundo probat idem: quia illae transmutationes opponuntur, quae sunt ex contrariis in contraria; generatio autem et putrefactio sunt huiusmodi: quia generatio incipit ab humido et sicco interminatis, et finitur ad terminationem ipsorum, putrefactio autem e converso incipit ab humido et sicco terminatis, et finitur ad divisionem ipsorum: nam quando virtutes activae obtinent passivas, calidum educendo humidum a sicco causat putrefactionem. Quod etiam apparet in aliis tribus elementis ab igne, quae putrescunt propter humidi eductionem factam a calido ignis; solus autem ignis non putrescit, quia nec habet humiditatem quae educatur a sicco, neque invenitur caliditas vincens caliditatem ignis.

Deinde cum dicit: putrefactio autem etc., determinat de corruptione opposita generationi simplici, quae est putrefactio. Et dicit quod putrefactio est corruptio propriae et naturalis caliditatis, facta a caliditate extrinseca, scilicet continentis, in humido naturali. Patitur autem res naturalis et putrefit a calido extrinseco, quia habet debilem caliditatem intrinsecam et est indigens caliditatis, et frigidum vincit caliditatem naturalem: ex quo sequitur quod tam caliditas extranea quam frigiditas intrinseca est causa putrefactionis; sed caliditas extrinseca est causa principalis, frigiditas est causa secundaria: quia quod patitur a calido extrinseco, patitur propter defectum caliditatis propriae, defectus autem caliditatis ponit frigiditatem contrariam abundantem, quae etiam agit ad expulsionem caliditatis intrinsecae. Quod autem putrefactio sit corruptio propriae caliditatis, probat: quia calido extrinseco educente humidum naturale per exsudationem, educit etiam caliditatem intrinsecam existentem in humido naturali: sunt enim coniuncta et trahunt se invicem propria caliditas et humidum naturale. Propter quod putrefacta prius, desiccantur interius et madescunt exterius, quia humidum foras educitur: deinde totaliter exterius desiccantur a calido totaliter resolvente humidum, et finaliter efficiuntur sicca, et ultimo resolvuntur in terram et fimum. Sed quod putrefactio sit a caliditate continentis, probat quinque signis sumptis ab his quae impediunt putrefactionem. Quorum primum est, quod in frigoribus res minus putrescunt quam in aestate, quia in hieme minor est caliditas continentis aeris vel aquae quam in aestate, et ideo minus potest putrefacere. Secundum est, quod id quod est coagulatum sive congelatum forti frigido, sicut sunt metalla, non putrescit, quia vehementia frigoris intrinseci vincit caliditatem extrinsecam. Tertium est, quod ea quae habent magnam caliditatem intrinsecam, non putrescunt, sicut piper et galanga, praecipue cum exsiccantur: quia tunc non est ibi humidum admixtum quod educi possit, quia caliditas intrinseca fortiter resistit extrinsecae. Quartum est, quod id quod movetur minus putrescit quam id quod stat, ut aqua fluvii minus putrescit quam aqua paludis: et ratio est, quia motus causat caliditatem in re mota, et ideo augetur et vigoratur caliditas rei motae et vincit caliditatem extrinsecam. Quinto, multum simul minus putrescit quam paucum: quia id quod est magnum sive multum habet maiorem ignem, idest maiorem caliditatem, quam quod est parvum, ut in pluribus, et etiam maiorem frigiditatem ceteris paribus, et ideo fortius resistit actioni caliditatis extrinsecae. Propter quod pauca aqua in lacuna citius putrescit quam magna aqua maris quae non putrescit, tum propter multitudinem, tum propter continuum motum. Quod autem dicitur hic, debet intelligi in continuis, et praesertim in simplicibus: quia multa frumenta citius putrescunt quam pauca. Quod autem putrefactio sit in humido probatur: quia animalia et cetera genita ex putrefactis generantur ex humido; ergo putrefactio fit in humido. Cum enim caliditas naturalis educitur, educit secum humidum subtile et segregat ipsum a re putrefacienda. Virtus autem caelestis tanquam principale agens, sed calor et humidum segregatum quod circumstat putrefactum loco virtutis formativae, generant animalia ex putrefactis.

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Lectio 3

2	2
λοιπὸν δ' εἰπεῖν τὰ ἐχόμενα εἴδη, ὅσα αἱ εἰρημέναι δυνάμεις ἐργάζονται ἐξ ὑποκειμένων τῶν φύσει συνεστώτων ἤδη. ἔστι δὴ θερμοῦ μὲν πέψις, πέψεως δὲ πέπανσις, ἕψησις, ἔτι ὄπτησις ψυχρότητος δὲ ἀπεψία, ταύτης δὲ ὠμότης, μόλυνσις, στάτευσις. δεῖ δὲ ὑπολαμβάνειν μὴ κυρίως ταῦτα λέγεσθαι τὰ ὀνόματα τοῖς πράγμασιν, ἀλλ' οὐ κεῖται καθόλου τοῖς ὁμοίοις, ὥστε οὐ ταῦτα ἀλλὰ τοιαῦτα δεῖ νομίζειν εἶναι τὰ εἰρημένα εἴδη. εἴπωμεν δ' αὐτῶν ἕκαστον τί ἐστιν. πέψις μὲν οὖν ἐστιν τελείωσις ὑπὸ τοῦ φυσικοῦ καὶ οἰκείου θερμοῦ ἐκ τῶν ἀντικειμένων παθητικῶν ταῦτα δ' ἐστὶν ἡ οἰκεία ἑκάστῳ ὕλη. ὅταν γὰρ πεφθῇ, τετελείωταί τε καὶ γέγονεν. καὶ ἡ ἀρχὴ τῆς τελειώσεως ὑπὸ θερμότητος τῆς οἰκείας συμβαίνει, κἂν διά τινος τῶν ἐκτὸς βοηθείας συνεπιτελεσθῇ, οἷον ἡ τροφὴ συμπέττεται καὶ διὰ λουτρῶν καὶ δι' ἄλλων τοιούτων ἀλλ' ἥ γε ἀρχὴ ἡ ἐν αὐτῷ θερμότης ἐστίν. τὸ δὲ τέλος τοῖς μὲν ἡ φύσις ἐστίν, φύσις δὲ ἣν λέγομεν ὡς εἶδος καὶ οὐσίαν τοῖς δὲ εἰς ὑποκειμένην τινὰ μορφὴν τὸ τέλος ἐστὶ τῆς πέψεως, ὅταν τοιονδὶ γένηται καὶ τοσονδὶ τὸ ὑγρὸν ἢ ὀπτώμενον ἢ ἑψόμενον ἢ σηπόμενον ἢ ἄλλως πως θερμαινόμενον τότε γὰρ χρήσιμόν ἐστι καὶ πεπέφθαι φαμέν, ὥσπερ τὸ γλεῦκος καὶ τὰ ἐν τοῖς φύμασιν συνιστάμενα, ὅταν γένηται πύον, καὶ τὸ δάκρυον, ὅταν γένηται λήμη ὁμοίως δὲ καὶ τἆλλα.	We must now describe the next kinds of processes which the qualities already mentioned set up in actually existing natural objects as matter. Of these concoction is due to heat; its species are ripening, boiling, broiling. Inconcoction is due to cold and its species are rawness, imperfect boiling, imperfect broiling. (We must recognize that the things are not properly denoted by these words: the various classes of similar objects have no names universally applicable to them; consequently we must think of the species enumerated as being not what those words denote but something like it.) Let us say what each of them is. Concoction is a process in which the natural and proper heat of an object perfects the corresponding passive qualities, which are the proper matter of any given object. For when concoction has taken place we say that a thing has been perfected and has come to be itself. It is the proper heat of a thing that sets up this perfecting, though external influences may contribute in some degrees to its fulfilment. Baths, for instance, and other things of the kind contribute to the digestion of food, but the primary cause is the proper heat of the body. In some cases of concoction the end of the process is the nature of the thing—nature, that is, in the sense of the formal cause and essence. In other cases it leads to some presupposed state which is attained when the moisture has acquired certain properties or a certain magnitude in the process of being broiled or boiled or of putrefying, or however else it is being heated. This state is the end, for when it has been reached the thing has some use and we say that concoction has taken place. Must is an instance of this, and the matter in boils when it becomes purulent, and tears when they become rheum, and so with the rest.
συμβαίνει δὲ τοῦτο πάσχειν ἅπασιν, ὅταν κρατηθῇ ἡ ὕλη καὶ ἡ ὑγρότης αὕτη γάρ ἐστιν ἡ ὁριζομένη ὑπὸ τῆς ἐν τῇ φύσει θερμότητος. ἕως γὰρ ἂν ἐνῇ ἐν αὐτῇ ὁ λόγος, φύσις τοῦτ' ἐστίν. (380a.) διὸ καὶ ὑγιείας σημεῖα τὰ τοιαῦτα, καὶ οὖρα καὶ ὑποχωρήσεις καὶ ὅλως τὰ περιττώματα. καὶ λέγεται πεπέφθαι, ὅτι δηλοῖ κρατεῖν τὴν θερμότητα τὴν οἰκείαν τοῦ ἀορίστου. ἀνάγκη δὲ τὰ πεττόμενα παχύτερα καὶ θερμότερα εἶναι τοιοῦτον γὰρ ἀποτελεῖ τὸ θερμόν, εὐογκότερον καὶ παχύτερον καὶ ξηρότερον. πέψις μὲν οὖν τοῦτο ἐστίν ἀπεψία δὲ ἀτέλεια δι' ἔνδειαν τῆς οἰκείας θερμότητος (ἡ δὲ ἔνδεια τῆς θερμότητος ψυχρότης ἐστίν) ἡ δ' ἀτέλειά ἐστιν τῶν ἀντικειμένων παθητικῶν, ἥπερ ἐστὶν ἑκάστῳ φύσει ὕλη. πέψις μὲν οὖν καὶ ἀπεψία διωρίσθω τοῦτον τὸν τρόπον.	Concoction ensues whenever the matter, the moisture, is mastered. For the matter is what is determined by the heat connatural to the object, and as long as the ratio between them exists in it a thing maintains its nature. Hence things like the liquid and solid excreta and ejecta in general are signs of health, and concoction is said to have taken place in them, for they show that the proper heat has got the better of the indeterminate matter. Things that undergo a process of concoction necessarily become thicker and hotter, for the action of heat is to make things more compact, thicker, and drier. This then is the nature of concoction: but inconcoction is an imperfect state due to lack of proper heat, that is, to cold. That of which the imperfect state is, is the corresponding passive qualities which are the natural matter of anything. So much for the definition of concoction and inconcoction.

Postquam philosophus determinavit de operationibus qualitatum primarum in constitutione et destitutione rei, nunc determinat de operationibus quae eius consequuntur rem in esse iam constituto. Et circa hoc duo facit: primo determinat de talibus operationibus secundum se; secundo de speciebus earum, ibi: pepansis autem et cetera. Circa primum duo facit: primo determinat de digestione quae est prima; secundo de indigestione ei opposita, ibi: indigestio autem et cetera. Circa primum iterum duo facit: primo definit digestionem; secundo ostendit quando et quomodo fiat, ibi: accidit autem hoc et cetera. Dicit ergo primo, quod post determinata reliquum est dicere de operationibus talium qualitatum, quae consequuntur res iam constitutas in esse, quae sunt istae. Calidi enim operatio in mixto est digestio. Digestionis autem species sunt pepansis, hepsesis et optesis. Frigiditatis autem operatio est indigestio: cuius indigestionis species sunt omotes, molynsis, et stateusis. Considerandum est autem sicut ipse dicit, quod haec nomina non sunt propria speciebus digestionis, sed sunt accommodata per quandam similitudinem et proportionem. Considerandum est iterum quod indigestionis est duplex causa: una per se, et haec est frigiditas: quia contrariarum causarum sunt effectus per se contrarii, si igitur caliditas est causa digestionis, frigiditas erit causa indigestionis; alia per accidens, et haec est remotio caliditatis: sicut enim praesentia caliditatis faciebat digestionem, ita ea remota remanet res indigesta. Sed quia remotio caliditatis ponit frigiditatem, absolute dicitur quod causa indigestionis est frigiditas. Est itaque digestio perfectio quaedam, idest transmutatio ducens ad esse perfectum, causata effective a proprio et naturali calido quod agit in virtute formae substantialis ex oppositis passivis, idest facta in qualitatibus passivis quae sunt oppositae isti, tanquam in materia. Fit enim digestio a proprio et naturali calido principaliter, secundario autem fit ab extrinsecis, sicut a balneis, ab exercitio moderato, et aliis fomentis calidi intrinseci et naturalis. Sed finis principalis istius digestionis est introductio naturae, idest formae nutriti, in materia quae digeritur: quia tunc dicimus esse factam digestionem cum in materia est introducta forma nutriti. Alius autem finis, et quasi secundarius, est quaedam forma accidentalis, scilicet calor introductus in materia digesta, qui facit evaporare humidum subtile et terminat grossum, sicut apparet in carne elixata et in musto: cum enim evaporavit humidum subtile, et grossum est terminatum et quasi induratum a calido, tunc dicimus ipsa esse digesta et cocta. Simile etiam apparet de lacrima et apostematibus: cum enim lacrima et putredo apostematis terminata fuerit a calido vincente et quasi ingrossata et facta quaedam lippitudo grossa, tunc dicimus ea esse digesta. Idem etiam ostendit superfluitas quae emittitur ex corpore, quae dum est liquida et subtilis, dicitur esse indigesta, cum autem est terminata per calidum et ingrossata, tunc est digesta et signum sanitatis.

Deinde cum dicit: accidit autem hoc etc., ostendit quomodo et quando fiat digestio. Et dicit quod digestio accidit quando calidum vincit humidum, quod est materia digestionis, quia solum humidum est quod naturaliter terminatur a calido: sicut accidit in superfluitatibus emissis, sicut supra dictum est; et propter hoc necesse est, ea quae sunt digesta esse sicciora et grossiora, propter evaporationem et terminationem humidi factam a calido.

Deinde cum dicit: indigestio autem etc., definit indigestionem oppositam digestioni. Et dicit quod indigestio est imperfectio facta in qualitatibus passivis propter indigentiam caliditatis propriae et naturalis: sed quia talis indigentia caliditatis est frigiditas, idest ponit frigiditatem, ideo indigestionis causa per se est frigiditas, causa vero per accidens est remotio caliditatis, sicut supra declaratum est. Quia autem contrariorum contrariae sunt definitiones, ideo sicut supra in definitione digestionis posuit perfectionem loco generis, caliditatem propriam ut efficiens, ita hic ponitur imperfectio loco generis, quia indigestio est via ad imperfectionem, scilicet ad putrefactionem, et ponitur frigiditas impediens digestionem ut efficiens: sed quia contrariorum est eadem materia, ideo utrobique ponitur qualitas passiva, idest humidum, ut materia. Non autem assignat aliquem finem indigestionis, quia indigestio non fit ad aliquem finem, sed praeter intentionem naturae: cum sit imperfectio, et finis habeat rationem boni et perfecti.

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Lectio 4

3	3
πέπανσις δ' ἐστὶν πέψις τις ἡ γὰρ τῆς ἐν τοῖς περικαρπίοις τροφῆς πέψις πέπανσις λέγεται. ἐπεὶ δ' ἡ πέψις τελέωσις, τότε ἡ πέπανσις τελέα ἐστὶν ὅταν τὰ ἐν τῷ περικαρπίῳ σπέρματα δύνηται ἀποτελεῖν τοιοῦτον ἕτερον οἷον αὐτό καὶ γὰρ ἐπὶ τῶν ἄλλων τὸ τέλεον οὕτω λέγομεν. περικαρπίου μὲν οὖν αὕτη πέπανσις, λέγεται δὲ καὶ ἄλλα πολλὰ πέπονα τῶν πεπεμμένων, κατὰ μὲν τὴν αὐτὴν ἰδέαν, μεταφοραῖς δέ, διὰ τὸ μὴ κεῖσθαι, καθάπερ εἴρηται καὶ πρότερον, ὀνόματα καθ' ἑκάστην τελείωσιν περὶ τὰ ὁριζόμενα ὑπὸ τῆς φυσικῆς θερμότητος καὶ ψυχρότητος. ἔστιν δὲ ἡ φυμάτων καὶ φλέγματος καὶ τῶν τοιούτων πέπανσις ἡ ὑπὸ τοῦ φυσικοῦ θερμοῦ τοῦ ἐνόντος ὑγροῦ πέψις ἀδύνατον γὰρ ὁρίζειν μὴ κρατοῦν. ἐκ μὲν οὖν τῶν πνευματικῶν ὑδατώδη, ἐκ δὲ τῶν τοιούτων τὰ γεηρὰ συνίσταται, καὶ ἐκ λεπτῶν αἰεὶ παχύτερα γίγνεται πεπαινόμενα πάντα. καὶ τὰ μὲν εἰς αὐτὴν ἡ φύσις ἄγει κατὰ τοῦτο, τὰ δὲ ἐκβάλλει.	Ripening is a sort of concoction; for we call it ripening when there is a concoction of the nutriment in fruit. And since concoction is a sort of perfecting, the process of ripening is perfect when the seeds in fruit are able to reproduce the fruit in which they are found; for in all other cases as well this is what we mean by 'perfect'. This is what 'ripening' means when the word is applied to fruit. However, many other things that have undergone concoction are said to be 'ripe', the general character of the process being the same, though the word is applied by an extension of meaning. The reason for this extension is, as we explained before, that the various modes in which natural heat and cold perfect the matter they determine have not special names appropriated to them. In the case of boils and phlegm, and the like, the process of ripening is the concoction of the moisture in them by their natural heat, for only that which gets the better of matter can determine it. So everything that ripens is condensed from a spirituous into a watery state, and from a watery into an earthy state, and in general from being rare becomes dense. In this process the nature of the thing that is ripening incorporates some of the matter in itself, and some it rejects.
πέπανσις μὲν οὖν εἴρηται τί ἐστιν ὠμότης δ' ἐστὶν τὸ ἐναντίον ἐναντίον δὲ πεπάνσει ἀπεψία τῆς ἐν τῷ περικαρπίῳ τροφῆς αὕτη δ' ἐστὶν ἡ ἀόριστος ὑγρότης. διὸ ἢ πνευματικὴ ἢ ὑδατώδης ἢ τῶν ἐξ ἀμφοῖν ἐστιν ἡ ὠμότης. ἐπεὶ δ' ἡ πέπανσις τελέωσίς τίς ἐστιν, ἡ ὠμότης ἀτέλεια ἔσται. γίγνεται δ' ἡ ἀτέλεια δι' ἔνδειαν τοῦ φυσικοῦ θερμοῦ καὶ ἀσυμμετρίαν πρὸς τὸ ὑγρὸν τὸ πεπαινόμενον. οὐδὲν δὲ ὑγρὸν αὐτὸ καθ' αὑτὸ πεπαίνεται ἄνευ ξηροῦ ὕδωρ γὰρ οὐ παχύνεται μόνον τῶν ὑγρῶν. (380b.) συμβαίνει δὲ τοῦτο ἢ τῷ τὸ θερμὸν ὀλίγον εἶναι ἢ τῷ τὸ ὁριζόμενον πολύ διὸ καὶ λεπτοὶ οἱ χυμοὶ τῶν ὠμῶν, καὶ ψυχροὶ μᾶλλον ἢ θερμοί, καὶ ἄβρωτοι καὶ ἄποτοι. λέγεται δὲ καὶ ἡ ὠμότης ὥσπερ καὶ ἡ πέπανσις, πολλαχῶς. ὅθεν καὶ οὖρα καὶ ὑποχωρήσεις καὶ κατάρροι ὠμοὶ λέγονται διὰ τὸ αὐτὸ αἴτιον τῷ γὰρ μὴ κεκρατῆσθαι ὑπὸ τῆς θερμότητος μηδὲ συνεστάναι ὠμὰ πάντα προσαγορεύεται. πόρρω δὲ προϊόντων καὶ κέραμος ὠμὸς καὶ γάλα ὠμὸν καὶ ἄλλα πολλὰ λέγεται, ἐὰν δυνάμενα μεταβάλλειν καὶ συνίστασθαι ὑπὸ θερμότητος ἀπαθῆ ᾖ. διὸ τὸ ὕδωρ ἑφθὸν μὲν λέγεται, ὠμὸν δ' οὔ, ὅτι οὐ παχύνεται. πέπανσις μὲν οὖν καὶ ὠμότης εἴρηται τί ἐστιν, καὶ διὰ τί ἐστιν ἑκάτερον αὐτῶν	So much for the definition of ripening. Rawness is its opposite and is therefore an imperfect concoction of the nutriment in the fruit, namely, of the undetermined moisture. Consequently a raw thing is either spirituous or watery or contains both spirit and water. Ripening being a kind of perfecting, rawness will be an imperfect state, and this state is due to a lack of natural heat and its disproportion to the moisture that is undergoing the process of ripening. (Nothing moist ripens without the admixture of some dry matter: water alone of liquids does not thicken.) This disproportion may be due either to defect of heat or to excess of the matter to be determined: hence the juice of raw things is thin, cold rather than hot, and unfit for food or drink. Rawness, like ripening, is used to denote a variety of states. Thus the liquid and solid excreta and catarrhs are called raw for the same reason, for in every case the word is applied to things because their heat has not got the mastery in them and compacted them. If we go further, brick is called raw and so is milk and many other things too when they are such as to admit of being changed and compacted by heat but have remained unaffected. Hence, while we speak of 'boiled' water, we cannot speak of raw water, since it does not thicken. We have now defined ripening and rawness and assigned their causes.

Agit de speciebus digestionis et indigestionis sibi oppositae. Et primo agit de pepansi, quae sola est naturalis species digestionis, aliae vero sunt magis artificiales; secundo agit de aliis speciebus, ibi: hepsesis autem et cetera. Circa primum duo facit: primo determinat de pepansi; secundo de omote ei opposita, ibi: omotes autem et cetera. Dicit ergo primo quod pepansis est digestio quaedam in pericarpiis, idest in illo tegmine sive cooperimento quod cooperit semen vel fructum, sive sit pellis in animalibus, sive cortex in fructibus. Et quia digestio ut dictum est, est perfectio, ideo et pepansis quae est eius species, est perfectio quaedam. Tunc enim res dicitur pepansim passa, quando semen in pericarpio potest efficere et generare tale, quale est id a quo procedit: in aliis enim perfectum etiam dicimus, quod potest generare tale quale est ipsum, ut declaratum est in II de anima. Est autem pepansis ab eodem agente, scilicet a naturali calido principaliter, et in eadem materia, scilicet in humido naturali, sicut superius dictum est de digestione in universali. Alio autem modo dicitur pepansis metaphorice: quia non eodem modo univoce, neque etiam pure aequivoce, sed analogice praedicatur pepansis de suis subiectis, sicut ridere de animali et prato viridi. Est autem pepansis metaphorice non solum in nutrimento viventium, sed etiam circa alia: ut circa nascentias, idest apostemata, et phlegmatica, ut sunt catarrhi, et circa urinas et secessiones. Et universaliter dicitur digestio pepansis metaphorice omnis maturatio et terminatio huiusmodi a naturali calido, quod fit, sicut dictum est, quando calidum obtinet super humidum: impossibile enim esset quod terminaret, nisi obtineret victoriam supra ipsum. Fit autem hoc modo. Nam primo calor digerens agit in humidum aereum, quod est spumosum, faciendo evaporare subtiliores partes, et ingrossando reliquas ac convertendo in humorem aquosum. Deinde subtiliando humorem aquosum facit ipsum evaporare, reliquum ingrossat, terminat et digerit, et ipsum coniungit cum sicco: et tunc convertitur in semen. Iste autem ordo apparet in animalibus et plantis. Nam in prima digestione separantur faeces: quando autem humidum cibi est reductum ad humorem aquosum, tunc in secunda digestione separatur urina: in tertia vero et quarta fit maturatio cibi, et conversio in semen. Hoc etiam apparet in omnibus pomis, et clare in amygdala, in qua prius a calido separatur humidum aereum, et convertitur flos in corticem viridem et aquosum, postea separatur humidum aquosum et convertitur in corticem osseum, et tertio semen intra formatur. Et ex hoc quasi in omnibus seminibus invenimus corticem extrinsecam magis aeream, secundam magis aqueam, et intra semen bene maturatum et digestum.

Deinde cum dicit: omotes autem etc., determinat de omote opposita pepansi. Et dicit quod est indigestio in pericarpio, sicut pepansis est digestio in eo: ut quando semina non possunt efficere tale quale ipsa sunt; et habet fieri circa humidum interminatum: quia illa quae patiuntur omoten, sunt spumosa aut aquosa, sive mixta ex his. Sicut autem pepansis est perfectio, sic et omotes est imperfectio, quae accidit propter indigentiam calidi et abundantiam frigidi. Cum enim calidum non est commensuratum et proportionatum humido, tunc sequitur omotes: quia nunquam fit pepansis in humido solo sine siccitate, quae fit a calido proportionato; et ex hoc sola aqua inter omnia humida non ingrossatur, quia caret siccitate. Fit autem omotes propter duas causas: aut scilicet propter defectum caliditatis, sicut dictum est: aut propter excessum humidi digerendi; tunc enim calor proprius non potest obtinere humidum, et sequitur indigestio. Signum autem huius est, quod omnes fructus et poma parva in suo genere et humida, sunt indigesta et non bene matura: calida vero et grossa sunt bene digesta, et talia sunt apta ad esum humanum. Et universaliter quaecumque patiuntur omoten, sunt magis frigida et subtilia et humida. Sicut autem pepansis non dicitur uno modo sed multis, et dicitur quandoque metaphorice, sic et omotes dicitur quandoque metaphorice, et est indigestio quae apparet in catarrhis senum, infirmorum et mulierum, et in pustulis et huiusmodi. Adhuc etiam dicitur omotes magis metaphorice in lateribus et lacte: quando enim calidum non obtinet super humidum in talibus, tunc dicuntur indigesta, sicut sensus manifestat. Digestio igitur fit a calido naturali primo et per se, a frigido autem per accidens. Frigidum enim extrinsece circumstans calidum concludit ipsum interius et non permittit ipsum evaporare, et sic retinendo calidum naturale interius, causat digestionem. In cuius signum ventres animalium sunt calidiores et magis digerunt in hieme, quam in aestate. Indigestio autem fit a frigido per se, a calido autem per accidens, sicut supra dictum est.

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Lectio 5

ἕψησις δ' ἐστὶν τὸ μὲν ὅλον πέψις ὑπὸ θερμότητος ὑγρᾶς τοῦ ἐνυπάρχοντος ἀορίστου ἐν τῷ ὑγρῷ, λέγεται δὲ τοὔνομα κυρίως μόνον ἐπὶ τῶν ἑψομένων. τοῦτο δ' ἂν εἴη, ὥσπερ εἴρηται, πνευματῶδες ἢ ὑδατῶδες. ἡ δὲ πέψις γίγνεται ἀπὸ τοῦ ἐν τῷ ὑγρῷ πυρός τὸ γὰρ ἐπὶ τῶν τηγάνων ὀπτᾶται (ὑπὸ γὰρ τοῦ ἔξωθεν θερμοῦ πάσχει, ἐν ᾧ δ' ἐστὶν ὑγρῷ, ποιεῖ ἐκεῖνο μᾶλλον ξηρόν, εἰς αὑτὸ ἀναλαμβάνον), τὸ δ' ἑψόμενον τοὐναντίον ποιεῖ (ἐκκρίνεται γὰρ ἐξ αὐτοῦ τὸ ὑγρὸν ὑπὸ τῆς ἐν τῷ ἔξω ὑγρῷ θερμασίας) διὸ ξηρότερα τὰ ἑφθὰ τῶν ὀπτῶν οὐ γὰρ ἀνασπᾷ εἰς ἑαυτὰ τὸ ὑγρὸν τὰ ἑψόμενα κρατεῖ γὰρ ἡ ἔξωθεν θερμότης τῆς ἐντός εἰ δ' ἐκράτει ἡ ἐντός, εἷλκεν ἂν εἰς ἑαυτήν. ἔστιν δ' οὐ πᾶν σῶμα ἑψητόν οὔτε γὰρ ἐν ᾧ μηδέν ἐστιν ὑγρόν, οἷον ἐν λίθοις, οὔτ' ἐν οἷς ἔνεστι μέν, ἀλλ' ἀδύνατον κρατηθῆναι διὰ πυκνότητα, οἷον ἐν τοῖς ξύλοις ἀλλ' ὅσα τῶν σωμάτων ἔχει ὑγρότητα παθητικὴν ὑπὸ τῆς ἐν τῷ ὑγρῷ πυρώσεως. λέγεται δὲ καὶ χρυσὸς ἕψεσθαι καὶ ξύλον καὶ ἄλλα πολλά, κατὰ μὲν τὴν ἰδέαν οὐ τὴν αὐτήν, μεταφορᾷ δέ οὐ γὰρ κεῖται ὀνόματα ταῖς διαφοραῖς. καὶ τὰ ὑγρὰ δὲ ἕψεσθαι λέγομεν, οἷον γάλα καὶ γλεῦκος, ὅταν ἐν τῷ ὑγρῷ ὁ χυμὸς εἰς εἶδός τι μεταβάλλῃ ὑπὸ τοῦ κύκλῳ καὶ ἔξωθεν πυρὸς θερμαίνοντος, ὥστε τρόπον τινὰ παραπλήσιον τῇ εἰρημένῃ (381a.) ἑψήσει ποιεῖ. (τέλος δὲ οὐ ταὐτὸ πᾶσιν, οὔτε ἑψομένοις οὔτε πεττομένοις, ἀλλὰ τοῖς μὲν πρὸς ἐδωδήν, τοῖς δὲ πρὸς ῥόφησιν, τοῖς δὲ πρὸς ἄλλην χρείαν, ἐπεὶ καὶ τὰ φάρμακα ἕψειν λέγομεν.)

Boiling is, in general, a concoction by moist heat of the indeterminate matter contained in the moisture of the thing boiled, and the word is strictly applicable only to things boiled in the way of cooking. The indeterminate matter, as we said, will be either spirituous or watery. The cause of the concoction is the fire contained in the moisture; for what is cooked in a frying-pan is broiled: it is the heat outside that affects it and, as for the moisture in which it is contained, it dries this up and draws it into itself. But a thing that is being boiled behaves in the opposite way: the moisture contained in it is drawn out of it by the heat in the liquid outside. Hence boiled meats are drier than broiled; for, in boiling, things do not draw the moisture into themselves, since the external heat gets the better of the internal: if the internal heat had got the better it would have drawn the moisture to itself. Not every body admits of the process of boiling: if there is no moisture in it, it does not (for instance, stones), nor does it if there is moisture in it but the density of the body is too great for it-to-be mastered, as in the case of wood. But only those bodies can be boiled that contain moisture which can be acted on by the heat contained in the liquid outside. It is true that gold and wood and many other things are said to be 'boiled': but this is a stretch of the meaning of the word, though the kind of thing intended is the same, the reason for the usage being that the various cases have no names appropriated to them. Liquids too, like milk and must, are said to undergo a process of 'boiling' when the external fire that surrounds and heats them changes the savour in the liquid into a given form, the process being thus in a way like what we have called boiling. The end of the things that undergo boiling, or indeed any form of concoction, is not always the same: some are meant to be eaten, some drunk, and some are intended for other uses; for instance dyes, too, are said to be 'boiled'.

ὥστε ὅσα παχύτερα δύναται γίγνεσθαι ἢ ἐλάττω ἢ βαρύτερα, ἢ τὰ μὲν αὐτῶν τοιαῦτα τὰ δ' ἐναντία, διὰ τὸ διακρινόμενα τὰ μὲν παχύνεσθαι τὰ δὲ λεπτύνεσθαι, ὥσπερ τὸ γάλα εἴς τε ὀρὸν καὶ πυετίαν, πάντα ἑψητά ἐστιν. τὸ δὲ ἔλαιον οὐχ ἕψεται αὐτὸ καθ' ἑαυτό, ὅτι τούτων οὐδὲν πάσχει. ἡ μὲν οὖν κατὰ τὴν ἕψησιν λεγομένη πέψις τοῦτ' ἐστίν καὶ οὐδὲν διαφέρει ἐν ὀργάνοις τεχνικοῖς καὶ φυσικοῖς ἐάν τι γίγνηται διὰ τὴν αὐτὴν γὰρ αἰτίαν πάντα ἔσται. μόλυνσις δὲ ἀπεψία μὲν ἡ ἐναντία ἑψήσει εἴη δ' ἂν ἐναντία ἥ τε πρώτη λεχθεῖσα ἀπεψία τοῦ ἐν τῷ σώματι ἀορίστου δι' ἔνδειαν τῆς ἐν τῷ ὑγρῷ τῷ πέριξ θερμότητος (ἡ δ' ἔνδεια μετὰ ψυχρότητος ὅτι ἐστίν, εἴρηται) γίγνεται δὲ διὰ κίνησιν ἄλλην ἐκκρούεται γὰρ ἡ πέττουσα, καὶ ἡ ἔνδεια δὲ ἢ διὰ τὸ πλῆθος τῆς ἐν τῷ ὑγρῷ ψυχρότητος ἢ διὰ τὸ ἐν τῷ ἑψομένῳ πλῆθος τότε γὰρ συμβαίνει τὴν ἐν τῷ ὑγρῷ θερμότητα πλείω μὲν εἶναι ἢ ὥστε μὴ κινῆσαι, ἐλάττω δὲ ἢ ὥστε ὁμαλῦναι καὶ συμπέψαι. διὸ σκληρότερα μὲν τὰ μεμωλυσμένα γίγνεται τῶν ἑφθῶν, τὰ δ' ὑγρὰ διωρισμένα μᾶλλον. ἕψησις μὲν οὖν καὶ μόλυνσις εἴρηται, καὶ τί ἐστιν καὶ διὰ τί ἐστιν

All those things then admit of 'boiling' which can grow denser, smaller, or heavier; also those which do that with a part of themselves and with a part do the opposite, dividing in such a way that one portion thickens while the other grows thinner, like milk when it divides into whey and curd. Oil by itself is affected in none of these ways, and therefore cannot be said to admit of 'boiling'. Such then is the pfcies of concoction known as 'boiling', and the process is the same in an artificial and in a natural instrument, for the cause will be the same in every case. Imperfect boiling is the form of inconcoction opposed to boiling. Now the opposite of boiling properly so called is an inconcoction of the undetermined matter in a body due to lack of heat in the surrounding liquid. (Lack of heat implies, as we have pointed out, the presence of cold.) The motion which causes imperfect boiling is different from that which causes boiling, for the heat which operates the concoction is driven out. The lack of heat is due either to the amount of cold in the liquid or to the quantity of moisture in the object undergoing the process of boiling. Where either of these conditions is realized the heat in the surrounding liquid is too great to have no effect at all, but too small to carry out the process of concocting uniformly and thoroughly. Hence things are harder when they are imperfectly boiled than when they are boiled, and the moisture in them more distinct from the solid parts. So much for the definition and causes of boiling and imperfect boiling.

Determinat de alia specie digestionis quae dicitur hepsesis, et fit tam ab arte quam a natura. Et dicit quod hepsesis secundum totum, idest uniformiter facta in omnibus partibus, ad differentiam aliarum digestionum quae non fiunt aequaliter omnibus partibus, vel secundum totum, idest in universali, est digestio humidi interminati et subtilis, facta a caliditate extrinseca existente in humido exteriori: propter quod nomen et ratio hepsesis convenit solis elixatis. Patet autem ex ista definitione quod superior species digestionis est magis naturalis, sicut diximus, quam sequentes; quia ille motus dicitur naturalis, qui est a principio intrinseco, sicut patet in II Physic.: pepansis autem est a caliditate intrinseca, reliquae autem ab extrinseca. Humidum vero interminatum circa quod fit hepsesis, est magis aqueum vel spumosum, quod digeritur per caliditatem humidi extrinseci, sicut patet quando carnes decoquuntur elixae. Digestio autem hepsesis fit ab humido extrinseco: ea enim quae elixantur, patiuntur a tali humido; sicut e converso ea quae assantur in frixoriis, agunt in ipsum humidum unctuosum, ipsum in se absorbendo: patiuntur autem a sicco calido ignis. Et in signum huius frixa sunt magis sicca exterius et humida interius: elixa vero e contrario sunt humida exterius, quia humefiunt ab humiditate circumstante, et magis sicca interius, quia per actionem humidi extrinseci, sive caliditatis eius, perdunt humidum proprium et non recipiunt alienum: frixa vero retinent proprium et suscipiunt alienum. Omnia igitur corpora quae habent multum humidum, et bene passibile a calido quod est in humido extrinseco, sunt elixabilia, ut carnes, pisces, olus et huiusmodi: quaecumque vero non habent multum humidum, ut lapides, aut si habent illud, non est bene passibile et educibile a caliditate extrinseca, sicut ligna, non sunt elixabilia. Quamvis metaphorice multa alia dicantur pati hepsesim et elixari, sicut aurum et ligna et multa alia: quae licet proprie non elixentur, tamen vocantur elixa per quandam similitudinem, eo quod non sunt adhuc imposita nomina omnibus differentiis rerum. Dicitur autem elixari aurum vel lignum, inquantum virtute ignis humidum extrinsecum exhalat et separatur ab eis. Eodem modo elixantur humida, scilicet mustum et lac, inquantum virtute ignis a musto separatur humidum aereum, et a lacte separatur serum. Dicit autem quod finis non est idem in omnibus elixatis, sicut erat superius in alia digestione: quia alia elixantur ad esum, alia ad sorbitionem et cetera. Notandum est autem diligenter quod in fine textus ultimo concludit, quod ista digestio fit tam a natura quam ab arte propter eandem causam. Nam sicut per artem carnes elixantur ab humido circumstante, ita natura humidum nutrimentale in pueris digerit per humidum et calidum circumfusum. Ad sensum enim manifestum est quod in pueris et mulieribus est maior humiditas, quae quasi elixat humidum cibi. Et hoc etiam accidit in phlegmaticis.

Deinde cum dicit: molynsis autem etc., determinat de specie indigestionis opposita hepsesi, quae dicitur molynsis. Et dicit quod molynsis est indigestio humidi interminati (quod dictum est esse elixabile), causata propter defectum caliditatis existentis in humido circumstante: talis autem defectus caliditatis est frigiditas, sicut supra dictum est. Et ista indigestio accidit propter duas causas: aut scilicet propter parvitatem caloris in humido circumstante, aut propter multitudinem humidi digerendi, quod a parvo calore non potest obtineri. Et propter hoc duriora sunt quae patiuntur molynsim, quam quae patiuntur hepsesim; quia parvus calor dissolvit humidum, sed non educit: et ideo iterum magis congelatur et quasi conglutinatur, et duriores res facit.

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Lectio 6

ὄπτησις δ' ἐστὶν πέψις ὑπὸ θερμότητος ξηρᾶς καὶ ἀλλοτρίας. διὰ τοῦτο κἂν ἕψων τις ποιῇ μεταβάλλειν καὶ πέττεσθαι, μὴ ὑπὸ τῆς τοῦ ὑγροῦ θερμότητος ἀλλ' ὑπὸ τῆς τοῦ πυρός, ὅταν τελεσθῇ, ὀπτὸν γίγνεται καὶ οὐχ ἑφθόν, καὶ τῇ ὑπερβολῇ προσκεκαῦσθαι λέγεται ὑπὸ ξηρᾶς δὲ θερμότητος γίγνεται ὅταν ξηρότερον γίγνηται ἐπιτελεσθέν. διὸ καὶ τὰ ἐκτὸς ξηρότερα τῶν ἐντός τὰ δ' ἑφθὰ τοὐναντίον. καὶ ἔργον ἐπὶ τῶν χειροκμήτων τὸ ὀπτῆσαι μεῖζον ἢ ἑψῆσαι χαλεπὸν γὰρ τὰ ἐκτὸς καὶ τὰ ἐντὸς ὁμαλῶς θερμαίνειν. ἀεὶ γὰρ τὰ ἐγγύτερον τοῦ πυρὸς ξηραίνεται (381b.) θᾶττον, ὥστε καὶ μᾶλλον. συνιόντων οὖν τῶν ἔξω πόρων οὐ δύναται ἐκκρίνεσθαι τὸ ἐνυπάρχον ὑγρόν, ἀλλ' ἐγκατακλείεται, ὅταν οἱ πόροι μύσωσιν. ὄπτησις μὲν οὖν καὶ ἕψησις γίγνονται μὲν τέχνῃ, ἔστιν δ', ὥσπερ λέγομεν, τὰ εἴδη καθόλου ταὐτὰ καὶ φύσει ὅμοια γὰρ τὰ γιγνόμενα πάθη, ἀλλ' ἀνώνυμα μιμεῖται γὰρ ἡ τέχνη τὴν φύσιν, ἐπεὶ καὶ ἡ τῆς τροφῆς ἐν τῷ σώματι πέψις ὁμοία ἑψήσει ἐστίν καὶ γὰρ ἐν ὑγρῷ καὶ θερμῷ ὑπὸ τῆς τοῦ σώματος θερμότητος γίγνεται. καὶ ἀπεψίαι ἔνιαι ὅμοιαι τῇ μολύνσει. καὶ ζῷον οὐκ ἐγγίγνεται ἐν τῇ πέψει, ὥσπερ τινές φασιν, ἀλλ' ἐν τῇ ἀποκρίσει σηπομένῃ ἐν τῇ κάτω κοιλίᾳ, εἶτ' ἐπανέρχεται ἄνω πέττεται μὲν γὰρ ἐν τῇ ἄνω κοιλίᾳ, σήπεται δ' ἐν τῇ κάτω τὸ ἀποκριθέν δι' ἣν δ' αἰτίαν, εἴρηται ἐν ἑτέροις. ἡ μὲν οὖν μόλυνσις τῇ ἑψήσει ἐναντίον τῇ δὲ ὡς ὀπτήσει λεγομένῃ πέψει ἔστι μέν τι ἀντικείμενον ὁμοίως, ἀνωνυμώτερον δέ. εἴη δ' ἂν οἷον εἰ γένοιτο στάτευσις ἀλλὰ μὴ ὄπτησις δι' ἔνδειαν θερμότητος, ἣ συμβαίη ἂν ἢ δι' ὀλιγότητα τοῦ ἔξω πυρὸς ἢ διὰ πλῆθος τοῦ ἐν τῷ ὀπτωμένῳ ὕδατος τότε γὰρ πλείων μέν ἐστιν ἢ ὥστε μὴ κινῆσαι, ἐλάττων δὲ ἢ ὥστε πέψαι. τί μὲν οὖν ἐστι πέψις καὶ ἀπεψία, καὶ πέπανσις καὶ ὠμότης, καὶ ἕψησις καὶ ὄπτησις καὶ τἀναντία τούτοις, εἴρηται.

Broiling is concoction by dry foreign heat. Hence if a man were to boil a thing but the change and concoction in it were due, not to the heat of the liquid but to that of the fire, the thing will have been broiled and not boiled when the process has been carried to completion: if the process has gone too far we use the word 'scorched' to describe it. If the process leaves the thing drier at the end the agent has been dry heat. Hence the outside is drier than the inside, the opposite being true of things boiled. Where the process is artificial, broiling is more difficult than boiling, for it is difficult to heat the inside and the outside uniformly, since the parts nearer to the fire are the first to get dry and consequently get more intensely dry. In this way the outer pores contract and the moisture in the thing cannot be secreted but is shut in by the closing of the pores. Now broiling and boiling are artificial processes, but the same general kind of thing, as we said, is found in nature too. The affections produced are similar though they lack a name; for art imitates nature. For instance, the concoction of food in the body is like boiling, for it takes place in a hot and moist medium and the agent is the heat of the body. So, too, certain forms of indigestion are like imperfect boiling. And it is not true that animals are generated in the concoction of food, as some say. Really they are generated in the excretion which putrefies in the lower belly, and they ascend afterwards. For concoction goes on in the upper belly but the excretion putrefies in the lower: the reason for this has been explained elsewhere. We have seen that the opposite of boiling is imperfect boiling: now there is something correspondingly opposed to the species of concoction called broiling, but it is more difficult to find a name for it. It would be the kind of thing that would happen if there were imperfect broiling instead of broiling proper through lack of heat due to deficiency in the external fire or to the quantity of water in the thing undergoing the process. For then we should get too much heat for no effect to be produced, but too little for concoction to take place. We have now explained concoction and inconcoction, ripening and rawness, boiling and broiling, and their opposites.

Determinat de optesi, quae est alia species digestionis, et definit eam. Et dicit quod optesis est digestio a caliditate sicca (ad differentiam hepsesis, quae est digestio a caliditate humida) et aliena: quod dicit ad differentiam pepansis, quae non est a caliditate aliena, idest extranea, sed est ab intrinseca: vel quia omnis digestio est a caliditate aliena ei quod digeritur, non ei quod digerit. Et ex hoc, si quis digerat carnes vel aliud per optesim, cum consummata fuerit digestio, illud tale erit assum et non elixum, et si talis caliditas sicca fuerit excessiva, dicetur adustum. Quod autem fiat a sicca caliditate, probat: quia ista digestio quae dicitur assatio, quae citius consummatur quam elixatio, desiccat partes extrinsecas, remanentibus humidis partibus interioribus; cuius ratio est, quia caliditas sicca sine humiditate, desiccando primo partes exteriores, constringit poros rei digerendae, et propter hoc humiditas resoluta interius non potest exire: et ideo non parvam subtilitatem dicit esse bene assare, ita quod exteriora et interiora regulariter et pariformiter sint decocta ab igne. Dicit autem quod optesis et hepsesis fiunt, non solum ab arte, sed a natura, sicut superius diximus. Et hoc probat: primo, quia ars in suis effectibus imitatur naturam; sicut ergo ars operatur in assando, ita prius didicit a natura. Secundo, quia sicut in corpore humano fit digestio similis hepsesi, ut apparet in pueris, ita etiam fit in eo digestio optesis: sicut est in iuvenibus, in quibus propter fortitudinem caloris, nutrimentum magis assatur quam elixetur; cuius signum est, quod superfluitates eorum sunt siccae adustae. Deducit autem corollarie ex dictis, quod animalia, idest vermes, non generantur in superiori ventre, scilicet stomachi, sed in inferiori. Et ratio est, quia talia animalia non generantur nisi in loco putrefactionis superfluitatum cibi, cum sint animalia genita per putrefactionem: superfluitates autem non putrefiunt in superiori ventre, sed in inferiori. Cuius ratio ut ipse dicit, dicta est alibi: colligi tamen potest ex superioribus. Putrefactio enim fit propter defectum caliditatis digerentis, et ex hoc debet fieri in illo loco in quo est talis defectus caliditatis, in superiori autem ventre non est defectus caliditatis, cum sit propinquus cordi in quo est sedes caliditatis naturalis, sed talis defectus est in ventre inferiori, qui magis distat a proprio loco caliditatis naturalis. Sciendum tamen est quod id quod hic dicitur, intelligi debet ut in pluribus, quia quandoque propter debilitatem virtutis digestivae, scilicet calidi naturalis, ex infirmitate provenientem, cibus non digeritur, sed putrefit in stomacho: quod patet ex foetore proveniente ex stomacho per eructationem, sive alia via; et ideo ibi etiam quandoque generantur vermes, qui aliquando eiiciuntur per os.

Deinde cum dicit: molynsis quidem igitur etc., determinat finaliter de indigestione opposita optesi, quae dicitur stateusis. Et dicit quod ista indigestio, licet sit parum nota, tamen eam definiendo dicimus, quod est indigestio facta propter defectum caliditatis siccae. Et fit propter duas causas, sicut supra in aliis declaravimus, scilicet aut propter parvitatem sicci caloris, aut propter multitudinem humidi digerendi. Deinde epilogat, et est clarum in littera.

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Lectio 7

4	4
τῶν δὲ παθητικῶν, τοῦ ὑγροῦ καὶ τοῦ ξηροῦ, λεκτέον τὰ εἴδη. εἰσὶν δ' αἱ μὲν ἀρχαὶ τῶν σωμάτων αἱ παθητικαὶ ὑγρὸν καὶ ξηρόν, τὰ δ' ἄλλα μεικτὰ μὲν ἐκ τούτων, ὁποτέρου δὲ μᾶλλον, τούτου μᾶλλον τὴν φύσιν ἐστίν, οἷον τὰ μὲν ξηροῦ μᾶλλον τὰ δ' ὑγροῦ. πάντα δὲ τὰ μὲν ἐντελεχείᾳ ἔσται, τὰ δ' ἐν τῷ ἀντικειμένῳ ἔχει δ' οὕτως τῆξις πρὸς τὸ τηκτόν.	We must now describe the forms taken by the passive qualities the moist and the dry. The elements of bodies, that is, the passive ones, are the moist and the dry; the bodies themselves are compounded of them and whichever predominates determines the nature of the body; thus some bodies partake more of the dry, others of the moist. All the forms to be described will exist either actually, or potentially and in their opposite: for instance, there is actual melting and on the other hand that which admits of being melted.
ἐπεὶ δ' ἐστὶν τὸ μὲν ὑγρὸν εὐόριστον, τὸ δὲ ξηρὸν δυσόριστον, ὅμοιόν τι τῷ ὄψῳ καὶ τοῖς ἡδύσμασι πρὸς ἄλληλα πάσχουσι τὸ γὰρ ὑγρὸν τῷ ξηρῷ αἴτιον τοῦ ὁρίζεσθαι, καὶ ἑκάτερον ἑκατέρῳ οἷον κόλλα γίγνεται, ὥσπερ καὶ (382a.) Ἐμπεδοκλῆς ἐποίησεν ἐν τοῖς φυσικοῖς "ἄλφιτον ὕδατι κολλήσας." καὶ διὰ τοῦτο ἐξ ἀμφοῖν ἐστιν τὸ ὡρισμένον σῶμα. λέγεται δὲ τῶν στοιχείων ἰδιαίτατα ξηροῦ μὲν γῆ, ὑγροῦ δὲ ὕδωρ. διὰ τοῦτο ἅπαντά τε τὰ ὡρισμένα σώματα ἐνταῦθα οὐκ ἄνευ γῆς καὶ ὕδατος (ὁποτέρου δὲ πλέον, κατὰ τὴν δύναμιν τούτου ἕκαστον φαίνεται) καὶ ἐν γῇ καὶ ἐν ὕδατι ζῷα μόνον ἐστίν, ἐν ἀέρι δὲ καὶ πυρὶ οὐκ ἔστιν, ὅτι τῶν σωμάτων ὕλη ταῦτα.	Since the moist is easily determined and the dry determined with difficulty, their relation to one another is like that of a dish and its condiments. The moist is what makes the dry determinable, and each serves as a sort of glue to the other—as Empedocles said in his poem on Nature, 'glueing meal together by means of water.' Thus the determined body involves them both. Of the elements earth is especially representative of the dry, water of the moist, and therefore all determinate bodies in our world involve earth and water. Every body shows the quality of that element which predominates in it. It is because earth and water are the material elements of all bodies that animals live in them alone and not in air or fire.
τῶν δὲ σωματικῶν παθημάτων ταῦτα πρῶτα ἀνάγκη ὑπάρχειν τῷ ὡρισμένῳ, σκληρότητα ἢ μαλακότητα ἀνάγκη γὰρ τὸ ἐξ ὑγροῦ καὶ ξηροῦ ἢ σκληρὸν εἶναι ἢ μαλακόν. ἔστι δὲ σκληρὸν μὲν τὸ μὴ ὑπεῖκον εἰς αὑτὸ κατὰ τὸ ἐπίπεδον, μαλακὸν δὲ τὸ ὑπεῖκον τῷ μὴ ἀντιπεριίστασθαι τὸ γὰρ ὕδωρ οὐ μαλακόν οὐ γὰρ ὑπείκει τῇ θλίψει τὸ ἐπίπεδον εἰς βάθος, ἀλλ' ἀντιπεριίσταται. ἁπλῶς μὲν οὖν σκληρὸν ἢ μαλακὸν τὸ ἁπλῶς τοιοῦτον, πρὸς ἕτερον δὲ τὸ πρὸς ἐκεῖνο τοιοῦτον. πρὸς μὲν οὖν ἄλληλα ἀόριστά ἐστιν τῷ μᾶλλον καὶ ἧττον ἐπεὶ δὲ πρὸς τὴν αἴσθησιν πάντα κρίνομεν τὰ αἰσθητά, δῆλον ὅτι καὶ τὸ σκληρὸν καὶ τὸ μαλακὸν ἁπλῶς πρὸς τὴν ἁφὴν ὡρίκαμεν, ὡς μεσότητι χρώμενοι τῇ ἁφῇ διὸ τὸ μὲν ὑπερβάλλον αὐτὴν σκληρόν, τὸ δ' ἐλλεῖπον μαλακὸν εἶναί φαμεν.	Of the qualities of bodies hardness and softness are those which must primarily belong to a determined thing, for anything made up of the dry and the moist is necessarily either hard or soft. Hard is that the surface of which does not yield into itself; soft that which does yield but not by interchange of place: water, for instance, is not soft, for its surface does not yield to pressure or sink in but there is an interchange of place. Those things are absolutely hard and soft which satisfy the definition absolutely, and those things relatively so which do so compared with another thing. Now relatively to one another hard and soft are indefinable, because it is a matter of degree, but since all the objects of sense are determined by reference to the faculty of sense it is clearly the relation to touch which determines that which is hard and soft absolutely, and touch is that which we use as a standard or mean. So we call that which exceeds it hard and that which falls short of it soft.

Determinat de passionibus qualitatum passivarum. Et circa hoc duo facit: primo determinat de eis secundum se; secundo determinat de eis per comparationem ad corpora, ibi: his autem passionibus et cetera. Et circa primum iterum duo facit: primo determinat de eis in generali; secundo determinat de singulis secundum speciem, ibi: corporalium autem passionum et cetera. Dicit ergo primo, quod dicendum est de passionibus primarum qualitatum passivarum et de speciebus earum. Hae autem qualitates sunt humidum et siccum, quorum passiones sunt primo determinandae, quia humidum et siccum sunt prima principia passiva omnium corporum mixtorum. Quod intelligendum est inquantum sunt passiva: calidum enim et frigidum, humidum et siccum, sunt prima principia corporum inquantum sunt substantiae, materia prima est primum principium passivum corporum, forma substantialis est primum principium activum. Omnia autem corpora aut sunt primo humida, sicut est aqua, aut primo sicca, sicut terra, aut sunt mixta ex his. Sed eorum quae sunt mixta ex his duobus, sicut medium ex extremis, sicut sunt composita ex elementis, quaedam magis accedunt ad unum extremum, quaedam vero ad alterum: et quae magis accedunt ad siccum, denominantur sicca a praedominio, ut ligna et lapides, quae autem magis accedunt ad humidum, dicuntur a praedominio humida. Talia autem dupliciter dicuntur, sicut omnia alia entia existentia in genere: quaedam enim sunt talia actu, sicut ea quae sunt liquida actu, dicuntur actu humida; quaedam vero sunt opposito modo, scilicet in potentia, ut id quod non est actu liquidum, sed est liquabile, sicut sunt metalla. Ratio autem quare ex ambobus composita sunt omnia elementata, est quia unum non potest bene consistere et terminari sine alio: quia humidum est male terminabile proprio termino et intrinseco, sed bene terminatur alieno et extrinseco termino, et ideo non potest terminari sine sicco, quod est bene terminabile proprio termino, idest intrinseco, et male alieno; similiter etiam siccum non terminatur sine humido, sed unum est alteri velut colla. Cuius simile accidit in pulmentis: ex farina enim sicca et aqua humida fit et conglutinatur panis; et Empedocles etiam physicus fecit collam tenacem ex farina et aqua, conglutinans unum alteri per calorem. Quod autem aqua sit primo humida et terra sit primo sicca, ipse probat per duas rationes: quarum prima talis est. Illud enim dicitur primo tale, ratione cuius alia sunt talia, sicut ad longum declaratum est in I posteriorum; sed omnia corpora terminata sive elementata, sunt humida vel sicca, inquantum sunt ex aqua vel ex terra: quia nullum talium corporum est sine aqua et terra; ergo aqua et terra sunt primo talia. Dicit autem omnia corpora terminata hic, scilicet inferius apud nos, ad differentiam corporum superiorum, quae sunt composita ex materia et forma, non tamen sunt terrea vel aquea, sed sunt terminata aequivoce cum istis inferioribus. Secunda vero ratio est, quia omnia naturaliter appetunt locum consimilem et proportionatum suae naturae, et naturaliter quiescunt in eo: quia locus naturaliter est conservativus locati, sicut patet in IV Physic.; igitur omnia animalia manent in terra et aqua naturaliter, ut in simili suae naturae loco, et ut nutriri et conservari possint ab elemento, quod primo habet qualitatem passivam quae praedominatur in eis. Licet autem aliqua animalia dicantur nutriri in alio elemento, ut aves in aere et salamandra in igne, tamen haec omnia nutriuntur ex terra et aqua, vel ex his quae nascuntur in eis, ut manifestum est in avibus. Salamandra autem per longum tempus nutritur in igne ex sicco terreo adusto et fumoso, propter convenientem similitudinem ad complexionem suam, quae maxime invenitur in nostro igne inferiori: quia non habemus hic ignem purum, sed admixtum terreo; non autem nutriretur in igne puro.

Deinde cum dicit: corporalium autem etc., determinat de speciebus qualitatum passivarum provenientibus ex humido et sicco: quarum primae sunt durum et molle. Et ideo primo determinat de duro et molli, et dicit quod omnia corpora quae generantur ex humido et sicco, sunt aut dura aut mollia: et ideo de eis primo dicendum est. Definit autem durum et molle, dicens quod durum est illud quod non cedit in seipsum tangenti secundum superficiem, ut lapis et lignum. Quod intelligendum est de tangente naturaliter et sine magna violentia: quia licet lignum cedat securi et ferrum malleo tangenti cum violentia, tamen dicitur durum quia non cedit tangenti naturaliter. Molle autem est, quod e converso cedit tangenti naturaliter sine magna violentia, et non circumstat tactui, sed cedit in profundum sui ipsius, sicut cera. Aqua autem non dicitur mollis, neque alia liquida, quia non deprimitur in profundum illa pars quae supponitur tactui, sed quasi diffugit ad latus: quod ipse vocat circumstare. Sed durum et molle dupliciter dicuntur, scilicet absolute et simpliciter, et per comparationem ad alterum, sicut lignum quod respectu cerae est durum, et per comparationem ad ferrum est molle. Quia autem in definitionibus praedictis cadit sensus tactus, ideo dicit quod durum et molle definivit per respectum ad tactum, quia universaliter omne sensibile definitur per comparationem ad sensum: sunt enim sensus et sensibile correlativa. Cognoscit autem sensus tactus qualitates mixtorum, secundum quod excedunt aut deficiunt a media qualitate organi tactus. Non enim potest eas cognoscere inquantum sunt omnino similes tactui, sicut probant rationes Alexandri; sed tamen illa qualitas quae non cognoscitur ab uno tactu propter omnimodam similitudinem, cognoscitur ab alio propter dissimilitudinem aliquam: quia non est omnino eadem qualitas media in organo tactus diversorum animalium. Et sic universaliter omnis qualitas tangibilis cognoscitur ab aliquo tactu.

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Lectio 8

5	5
ἀνάγκη δὲ σκληρὸν ἢ μαλακὸν εἶναι τὸ ὡρισμένον σῶμα οἰκείῳ ὅρῳ (ἢ γὰρ ὑπείκει ἢ μή) ἔτι πεπηγὸς εἶναι (τούτῳ γὰρ ὁρίζεται) ὥστ' ἐπεὶ πᾶν μὲν τὸ ὡρισμένον καὶ συνεστὸς ἢ μαλακὸν ἢ σκληρόν, ταῦτα δὲ πήξει ἐστίν, ἅπαντ' ἂν εἴη τὰ σώματα τὰ σύνθετα καὶ ὡρισμένα οὐκ ἄνευ πήξεως. πήξεως οὖν πέρι ῥητέον. ἔστιν δὴ τὰ αἴτια τὰ παρὰ τὴν ὕλην δύο, τό τε ποιοῦν καὶ τὸ πάθος (τὸ μὲν οὖν ποιοῦν ὡς ὅθεν ἡ κίνησις, τὸ δὲ πάθος ὡς εἶδος) ὥστε καὶ πήξεως καὶ διαχύσεως, καὶ τοῦ ξηραίνεσθαι καὶ τοῦ ὑγραίνεσθαι. ποιεῖ δὲ τὸ ποιοῦν δυσὶ δυνάμεσι, καὶ πάσχει παθήμασιν δυσίν, ὥσπερ εἴρηται ποιεῖ μὲν θερμῷ καὶ ψυχρῷ, τὸ δὲ πάθος ἢ ἀπουσίᾳ ἢ παρουσίᾳ θερμοῦ ἢ (382b.) ψυχροῦ. ἐπεὶ δὲ τὸ πήγνυσθαι ξηραίνεσθαί πώς ἐστιν, περὶ τούτου εἴπωμεν πρῶτον. τὸ δὴ πάσχον ἢ ὑγρὸν ἢ ξηρὸν ἢ ἐκ τούτων. τιθέμεθα δὲ ὑγροῦ σῶμα ὕδωρ, ξηροῦ δὲ γῆν ταῦτα γὰρ τῶν ὑγρῶν καὶ τῶν ξηρῶν παθητικά. διὸ καὶ τὸ ψυχρὸν τῶν παθητικῶν μᾶλλον ἐν τούτοις γάρ ἐστιν καὶ γὰρ ἡ γῆ καὶ τὸ ὕδωρ ψυχρὰ ὑπόκειται. ποιητικὸν δὲ τὸ ψυχρὸν ὡς φθαρτικὸν ἢ ὡς κατὰ συμβεβηκός, καθάπερ εἴρηται πρότερον ἐνίοτε γὰρ καὶ κάειν λέγεται καὶ θερμαίνειν τὸ ψυχρόν, οὐχ ὡς τὸ θερμόν, ἀλλὰ τῷ συνάγειν ἢ ἀντιπεριιστάναι τὸ θερμόν.	A body determined by its own boundary must be either hard or soft; for it either yields or does not. It must also be concrete: or it could not be so determined. So since everything that is determined and solid is either hard or soft and these qualities are due to concretion, all composite and determined bodies must involve concretion. Concretion therefore must be discussed. Now there are two causes besides matter, the agent and the quality brought about, the agent being the efficient cause, the quality the formal cause. Hence concretion and disaggregation, drying and moistening, must have these two causes. But since concretion is a form of drying let us speak of the latter first. As we have explained, the agent operates by means of two qualities and the patient is acted on in virtue of two qualities: action takes place by means of heat or cold, and the quality is produced either by the presence or by the absence of heat or cold; but that which is acted upon is moist or dry or a compound of both. Water is the element characterized by the moist, earth that characterized by the dry, for these among the elements that admit the qualities moist and dry are passive. Therefore cold, too, being found in water and earth (both of which we recognize to be cold), must be reckoned rather as a passive quality. It is active only as contributing to destruction or incidentally in the manner described before; for cold is sometimes actually said to burn and to warm, but not in the same way as heat does, but by collecting and concentrating heat.
ξηραίνεται δὲ ὅσα ἐστὶν ὕδωρ καὶ ὕδατος εἴδη, ἢ ἔχει ὕδωρ εἴτ' ἐπακτὸν εἴτε συμφυές (λέγω δὲ ἐπακτὸν μὲν οἷον ἐν ἐρίῳ, σύμφυτον δ' οἷον ἐν γάλακτι). ὕδατος δ' εἴδη τὰ τοιάδε, οἶνος, οὖρον, ὀρός, καὶ ὅλως ὅσα μηδεμίαν ἢ βραχεῖαν ἔχει ὑπόστασιν, μὴ διὰ γλισχρότητα ἐνίοις γὰρ αἴτιον τοῦ μὴ ὑφίστασθαι μηδὲν ἡγλισχρότης, ὥσπερ ἐλαίῳ ἢ πίττῃ. ξηραίνεται δὲ πάντα ἢ θερμαινόμενα ἢ ψυχόμενα, ἀμφότερα δὲ θερμῷ, καὶ ὑπὸ τῆς ἐντὸς θερμότητος ἢ τῆς ἔξω καὶ γὰρ τὰ τῇ ψύξει ξηραινόμενα, ὥσπερ ἱμάτιον, ἐὰν ᾖ κεχωρισμένον αὐτὸ καθ' αὑτὸ τὸ ὑγρόν, ὑπὸ τοῦ ἐντὸς θερμοῦ συνεξατμίζοντος τὸ ὑγρὸν ξηραίνεται, ἂν ὀλίγον ᾖ τὸ ὑγρόν, ἐξιούσης τῆς θερμότητος ὑπὸ τοῦ περιεστῶτος ψυχροῦ. ξηραίνεται μὲν οὖν, ὥσπερ εἴρηται, ἅπαντα ἢ θερμαινόμενα ἢ ψυχόμενα, καὶ πάντα θερμῷ, ἢ τῷ ἐντὸς ἢ τῷ ἐκτὸς συνεξατμίζοντι τὸ ὑγρόν (λέγω δ' ἐκτὸς μὲν ὥσπερ τὰ ἑψόμενα, ἐντὸς δὲ ὅταν ἀφαιρεθέντος ὑφ' ἧς ἔχει θερμότητος ἀναλωθῇ ἀποπνεούσης). περὶ μὲν οὖν τοῦ ξηραίνεσθαι εἴρηται.	The subjects of drying are water and the various watery fluids and those bodies which contain water either foreign or connatural. By foreign I mean like the water in wool, by connatural, like that in milk. The watery fluids are wine, urine, whey, and in general those fluids which have no sediment or only a little, except where this absence of sediment is due to viscosity. For in some cases, in oil and pitch for instance, it is the viscosity which prevents any sediment from appearing. It is always a process of heating or cooling that dries things, but the agent in both cases is heat, either internal or external. For even when things are dried by cooling, like a garment, where the moisture exists separately it is the internal heat that dries them. It carries off the moisture in the shape of vapour (if there is not too much of it), being itself driven out by the surrounding cold. So everything is dried, as we have said, by a process either of heating or cooling, but the agent is always heat, either internal or external, carrying off the moisture in vapour. By external heat I mean as where things are boiled: by internal where the heat breathes out and takes away and uses up its moisture. So much for drying.
6	6
τὸ δ' ὑγραίνεσθαί ἐστιν ἓν μὲν τὸ ὕδωρ γίγνεσθαι συνιστάμενον, ἓν δὲ τὸ τήκεσθαι τὸ πεπηγός.	Liquefaction is, first, condensation into water; second, the melting of a solidified body. The first, condensation, is due to the cooling of vapour: what melting is will appear from the account of solidification.

Determinat de coagulatione et liquefactione et aliis passionibus, quibus differunt corpora secundum quod tangibilia sunt. Et circa hoc duo facit: primo determinat de siccari et humectari, quia omnis coagulatio est quaedam siccatio, liquefieri autem est humectari; secundo determinat de ipsa coagulatione et liquefactione et aliis speciebus, ibi: de liquefactione autem et cetera. Prima iterum in duas: primo enim determinat de siccatione; secundo de humectatione, ibi: humectari autem et cetera. Circa primum duo facit: primo praemittit intentionem suam; secundo exsequitur propositum, ibi: desiccantur autem et cetera. Dicit ergo primo quod, quia sicut dictum est, omne corpus terminatum est durum aut molle, si sit terminatum proprio termino (quod dicit propter liquida, quae non terminantur proprio termino, nisi ex magna violentia frigidi), terminatio autem non fit sine coagulatione quadam, ideo omnia corpora composita, scilicet ex elementis, non sunt sine coagulatione. Ideo prius de ea dicendum est. Sed tamen, quia sicut dictum est, praeter materiam sunt duae causae entium, scilicet faciens, idest qualitas activa, et passio, idest qualitas passiva, quae est quasi materia ex qua educitur forma et species, licet non sit proprie materia, sed instrumentum materiae quo materia patitur, sicut qualitates activae sunt instrumenta quibus agens agit, et talia instrumenta materiae sunt duo, scilicet humidum et siccum, sicut et instrumenta agentis sunt duo, scilicet calidum et frigidum, ideo prius de humectari et siccari dicendum est quam de coagulatione. Primum enim quo materia patitur est humidum et siccum: et prima corpora passibilia sunt terra et aqua, quae sunt sicca et humida. Et propter hoc frigidum quod convenit terrae et aquae, est minus activum et magis passibile quam calidum, quod convenit aeri et igni. Quomodo autem frigidum sit activum ostendit, dicens quod est activum dupliciter. Primo quia corrumpere est quoddam agere: frigidum autem est corruptivum, quia corrumpit calidum, quae est qualitas generativa; secundo dicitur agere per accidens, quia circumstat calidum, et ex hoc calidum per antiperistasim, hoc est contrasistentiam frigidi, fortificatur, et sic frigidum fortificando calidum per accidens agit ad generationem. Sed considerandum est quantum ad hoc quod dicitur, quod frigiditas est per se corruptiva et per accidens generativa, quod generatio dupliciter dicitur, sicut supra dictum est: primo inquantum est mutatio a non esse ad esse absolute; secundo dicitur generatio, quando id quod producitur in esse, est nobilius, et e converso quod corrumpitur, est ignobilius: corruptio vero dicitur, quando quod corrumpitur, est nobilius, licet etiam ibi generetur aliquid aliud absolute; ut generatio dicitur, quando ex terra vel aqua generatur aer vel ignis, corruptio, quando e contrario ex igne vel aere generatur aqua vel terra. Et hoc modo agitur de generatione in I de generatione. Loquendo igitur de generatione primo modo, frigiditas est per se generativa, et non solum per accidens, quia corruptio unius est generatio alterius, et quod per se corrumpit unum, eadem actione generat per se reliquum: natura enim non operaretur per se intendens ad solam corruptionem, quae est quoddam malum, nisi eadem actione aliquid generaret. Sed de generatione secundo modo verum est quod frigidum per se est solummodo corruptivum: quia frigiditas corrumpit ignem et aerem, quae sunt nobiliora, et generat terram et aquam, quae sunt ignobiliora.

Deinde cum dicit: desiccantur autem etc., determinat de siccari exsequendo intentionem propositam. Et dicit quod omnia illa dicuntur desiccari quae sunt aqua aut aquae species, sicut vinum, serum et huiusmodi, aut quae habent humiditatem connaturalem, ut lac, vel superinductam, velut lana madefacta, et universaliter omnia humida, quae non faciunt residentiam in fundo propter puritatem, et non propter viscositatem. Quod dicit, quia sunt quaedam quae sunt terrea et grossa, et tamen partes terreae non resident in profundo propter viscositatem continentem siccum terrestre, sicut oleum et pix. Omnia autem ista aut desiccantur a calido exteriori foras educente humidum, sicut patet in carne elixata: aut a calido interiori et a frigore circumstante, quod fortificat calidum interius per antiperistasim, sicut apparet in indumentis desiccatis in hieme a vento frigido. Et sic omnia desiccantur aut a frigido per accidens, aut per se a calido, sive interiori sive exteriori.

Deinde cum dicit: humectari autem etc., ostendit quid sit humectari. Et dicit quod humectari dicitur dupliciter: uno quidem modo est fieri aquam, sicut cum ex nube generatur aqua pluviae; secundo modo humectari est liquefieri, sicut cum glacies vel metalla liquescunt. Hoc autem provenit non ab eadem causa, sed a diversis: humectantur enim res primo modo a frigido condensante vaporem in aquam, sicut supra dictum est, humectatio autem secundo modo fit a calido resolvente.

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Lectio 9

τούτων δὲ συνίσταται μὲν ψυχόμενον τὸ πνεῦμα περὶ δὲ τήξεως ἅμα καὶ περὶ πήξεως ἔσται δῆλον. πήγνυται δὲ ὅσα πήγνυται ἢ ὕδατος ὄντα ἢ γῆς καὶ ὕδατος, καὶ ταῦτα ἢ θερμῷ ξηρῷ ἢ ψυχρῷ. διὸ καὶ λύεται τοῖς ἐναντίοις, ὅσα (383a.) λύεται τῶν ὑπὸ θερμοῦ παγέντων ἢ ὑπὸ ψυχροῦ τὰ μὲν γὰρ ὑπὸ ξηροῦ θερμοῦ παγέντα ὑπὸ ὕδατος λύεται, ὅ ἐστιν ὑγρὸν ψυχρόν, τὰ δὲ ὑπὸ ψυχροῦ παγέντα ὑπὸ πυρὸς λύεται, ὅ ἐστιν θερμόν. πήγνυσθαι δ' ἔνια δόξειεν ἂν ὑπὸ ὕδατος, ὡς τὸ μέλι τὸ ἑφθόν πήγνυται δὲ οὐχ ὑπὸ τοῦ ὕδατος, ἀλλ' ὑπὸ τοῦ ἐν αὐτῷ ψυχροῦ. ὅσα μὲν οὖν ἐστιν ὕδατος, οὐ πήγνυται ὑπὸ πυρός λύεται γὰρ ὑπὸ πυρός, τὸ δὲ αὐτὸ τῷ αὐτῷ κατὰ ταὐτὸ οὐκ ἔσται αἴτιον τοῦ ἐναντίου. ἔτι τῷ ἀπιέναι τὸ θερμὸν πήγνυται, ὥστε δῆλον ὅτι τῷ εἰσιέναι λυθήσεται ὥστε ποιοῦντος τοῦ ψυχροῦ πήγνυται.	Whatever solidifies is either water or a mixture of earth and water, and the agent is either dry heat or cold. Hence those of the bodies solidified by heat or cold which are soluble at all are dissolved by their opposites. Bodies solidified by the dry-hot are dissolved by water, which is the moist-cold, while bodies solidified by cold are dissolved by fire, which is hot. Some things seem to be solidified by water, e.g. boiled honey, but really it is not the water but the cold in the water which effects the solidification. Aqueous bodies are not solidified by fire: for it is fire that dissolves them, and the same cause in the same relation cannot have opposite effects upon the same thing. Again, water solidifies owing to the departure of heat; so it will clearly be dissolved by the entry into it of heat: cold, therefore, must be the agent in solidifying it.
διὸ καὶ οὐ παχύνεται τὰ τοιαῦτα πηγνύμενα ἡ γὰρ πάχυνσις ὑγροῦ μὲν ἀπιόντος γίγνεται, τοῦ ξηροῦ δὲ συνισταμένου ὕδωρ δὲτῶν ὑγρῶν οὐ παχύνεται μόνον. ὅσα δὲ κοινὰ γῆς καὶ ὕδατος, καὶ ὑπὸ πυρὸς πήγνυται καὶ ὑπὸ ψυχροῦ, παχύνεται δὲ ὑπ' ἀμφοῖν ἔστι μὲν ὡς τὸν αὐτὸν τρόπον, ἔστι δ' ὡς ἄλλως, ὑπὸ μὲν θερμοῦ τὸ ὑγρὸν ἐξάγοντος (ἐξατμίζοντος γὰρ τοῦ ὑγροῦ παχύνεται τὸ ξηρὸν καὶ συνίσταται), ὑπὸ δὲ ψυχροῦ τὸ θερμὸν ἐκθλίβοντος, μεθ' οὗ τὸ ὑγρὸν συναπέρχεται συνεξατμίζον. ὅσα μὲν οὖν μαλακὰ ἀλλὰ μὴ ὑγρά, οὐ παχύνεται ἀλλὰ πήγνυται ἐξιόντος τοῦ ὑγροῦ, οἷον ὁ ὀπτώμενος κέραμος ὅσα δὲ ὑγρὰ τῶν μεικτῶν, καὶ παχύνεται, οἷον γάλα. πολλὰ δὲ καὶ ὑγραίνεται πρῶτον, ὅσα ἢ παχέα ἢ σκληρὰ ὑπὸ ψυχροῦ προϋπῆρχεν ὄντα, ὥσπερ καὶ ὁ κέραμος τὸ πρῶτον ὀπτώμενος ἀτμίζει καὶ μαλακώτερος γίγνεται διὸ καὶ διαστρέφεται ἐν ταῖς καμίνοις.	Hence aqueous bodies do not thicken when they solidify; for thickening occurs when the moisture goes off and the dry matter comes together, but water is the only liquid that does not thicken. Those bodies that are made up of both earth and water are solidified both by fire and by cold and in either case are thickened. The operation of the two is in a way the same and in a way different. Heat acts by drawing off the moisture, and as the moisture goes off in vapour the dry matter thickens and collects. Cold acts by driving out the heat, which is accompanied by the moisture as this goes off in vapour with it. Bodies that are soft but not liquid do not thicken but solidify when the moisture leaves them, e.g. potter's clay in process of baking: but those mixed bodies that are liquid thicken besides solidifying, like milk. Those bodies which have first been thickened or hardened by cold often begin by becoming moist: thus potter's clay at first in the process of baking steams and grows softer, and is liable to distortion in the ovens for that reason.
ὅσα μὲν οὖν ὑπὸ ψυχροῦ πήγνυται τῶν κοινῶν γῆς καὶ ὕδατος, πλέον δὲ ἐχόντων γῆς, τὰ μὲν τῷ τὸ θερμὸν ἐξεληλυθέναι πηγνύμενα, ταῦτα τήκεται θερμῷ εἰσιόντος πάλιν τοῦ θερμοῦ, οἷον ὁ πηλὸς ὅταν παγῇ ὅσα δὲ διὰ ψύξιν, καὶ τοῦ θερμοῦ συνεξατμίσαντος ἅπαντος, ταῦτα δὲ ἄλυτα μὴ ὑπερβαλλούσῃ θερμότητι, ἀλλὰ μαλάττεται, οἷον σίδηρος καὶ κέρας. τήκεται δὲ καὶ ὁ εἰργασμένος σίδηρος, ὥστε ὑγρὸς γίγνεσθαι καὶ πάλιν πήγνυσθαι. καὶ τὰ στομώματα ποιοῦσιν οὕτως ὑφίσταται γὰρ καὶ ἀποκαθαίρεται κάτω (383b.) ἡ σκωρία ὅταν δὲ πολλάκις πάθῃ καὶ καθαρὸς γένηται, τοῦτο στόμωμα γίγνεται. οὐ ποιοῦσι δὲ πολλάκις αὐτὸ διὰ τὸ ἀπουσίαν γίγνεσθαι πολλὴν καὶ τὸν σταθμὸν ἐλάττω ἀποκαθαιρομένου. ἔστιν δ' ἀμείνων σίδηρος ὁ ἐλάττω ἔχων ἀποκάθαρσιν. τήκεται δὲ καὶ ὁ λίθος ὁ πυρίμαχος ὥστε στάζειν καὶ ῥεῖν τὸ δὲ πηγνύμενον ὅταν ῥυῇ, πάλιν γίγνεται σκληρόν. καὶ αἱ μύλαι τήκονται ὥστε ῥεῖν τὸ δὲ ῥέον πηγνύμενον τὸ μὲν χρῶμα μέλαν, ὅμοιον δὲ γίγνεται τῇ τιτάνῳ.	Now of the bodies solidified by cold which are made up both of earth and water but in which the earth preponderates, those which solidify by the departure of heat melt by heat when it enters into them again; this is the case with frozen mud. But those which solidify by refrigeration, where all the moisture has gone off in vapour with the heat, like iron and horn, cannot be dissolved except by excessive heat, but they can be softened—though manufactured iron does melt, to the point of becoming fluid and then solidifying again. This is how steel is made. The dross sinks to the bottom and is purged away: when this has been done often and the metal is pure we have steel. The process is not repeated often because the purification of the metal involves great waste and loss of weight. But the iron that has less dross is the better iron. The stone pyrimachus, too, melts and forms into drops and becomes fluid; after having been in a fluid state it solidifies and becomes hard again. Millstones, too, melt and become fluid: when the fluid mass begins to solidify it is black but its consistency comes to be like that of lime. and earth, too
τήκεται δὲ καὶ ὁ πηλὸς καὶ ἡ γῆ. ὅσα δ' ὑπὸ ξηροῦ θερμοῦ πήγνυται, τὰ μὲν ἄλυτα, τὰ δὲ λυτὰ ὑγρῷ. κέραμος μὲν οὖν καὶ λίθων ἐνίων γένη, ὅσοι ὑπὸ πυρὸς τῆς γῆς συγκαυθείσης γίγνονται, οἷον οἱ μυλίαι, ἄλυτα, νίτρον δὲ καὶ ἅλες λυτὰ ὑγρῷ, οὐ παντὶ δὲ ἀλλὰ ψυχρῷ διὸ ὕδατι καὶ ὅσα ὕδατος εἴδη τήκεται, ἐλαίῳ δ' οὐ τήκεται τῷ γὰρ ξηρῷ θερμῷ ἐναντίον ψυχρὸν ὑγρόν. εἰ οὖν ἔπηξεν θάτερον, θάτερον λύσει οὕτω γὰρ τἀναντία ἔσται αἴτια τῶν ἐναντίων.	Of the bodies which are solidified by dry heat some are insoluble, others are dissolved by liquid. Pottery and some kinds of stone that are formed out of earth burnt up by fire, such as millstones, cannot be dissolved. Natron and salt are soluble by liquid, but not all liquid but only such as is cold. Hence water and any of its varieties melt them, but oil does not. For the opposite of the dry-hot is the cold-moist and what the one solidified the other will dissolve, and so opposites will have opposite effects.
7	7
παχύνεται μὲν οὖν ὑπὸ πυρὸς μόνον, ὅσα ὕδατος πλέον ἔχει ἢ γῆς, πήγνυται δέ, ὅσα γῆς. διὸ καὶ τὸ νίτρον καὶ οἱ ἅλες γῆς εἰσιν μᾶλλον, καὶ λίθος καὶ κέραμος. ἀπορώτατα δὲ ἔχει ἡ τοῦ ἐλαίου φύσις. εἰ μὲν γὰρ ὕδατος, ἔδει πήγνυσθαι ὑπὸ ψυχροῦ, εἰ δὲ γῆς πλέον, ὑπὸ πυρός νῦν δὲ πήγνυται μὲν ὑπ' οὐδετέρου, παχύνεται δὲ ὑπ' ἀμφοῖν. αἴτιον δ' ἐστὶν ὅτι ἀέρος ἐστὶν πλῆρες. διὸ καὶ ἐν τῷ ὕδατι ἐπιπολάζει καὶ γὰρ ὁ ἀὴρ φέρεται ἄνω. τὸ μὲν οὖν ψυχρὸν ἐκ τοῦ ἐνόντος πνεύματος ὕδωρ ποιοῦν παχύνει ἀεὶ γάρ, ὅταν μειχθῇ ὕδωρ καὶ ἔλαιον, ἀμφοῖν γίγνεται παχύτερον. ὑπὸ δὲ πυρὸς καὶ χρόνου παχύνεται καὶ λευκαίνεται, λευκαίνεται μὲν ἐξατμίζοντος εἴ τι ἐνῆν ὕδατος, παχύνεται δὲ διὰ τὸ μαραινομένου τοῦ θερμοῦ ἐκ τοῦ ἀέρος γίγνεσθαι ὕδωρ. ἀμφοτέρως μὲν οὖν τὸ αὐτὸ γίγνεται πάθος, καὶ διὰ τὸ αὐτό, ἀλλ' οὐχ ὡσαύτως. παχύνεται μὲν οὖν ὑπ' ἀμφοτέρων, οὐ ξηραίνεται δ' ὑπ' οὐδετέρου οὔτε γὰρ ὁ ἥλιος οὔτε τὸ ψῦχος ξηραίνει οὐ μόνον διότι γλίσχρον, (384a.) ἀλλὰ καὶ διότι ἀέρος ἐστίν. οὐ ξηραίνεται δὲ τὸ ὕδωρ οὐδ' ἕψεται ὑπὸ πυρός, ὅτι οὐκ ἀτμίζει διὰ γλισχρότητα.	If a body contains more water than earth fire only thickens it: if it contains more earth fire solidifies it. Hence natron and salt and stone and potter's clay must contain more earth. The nature of oil presents the greatest problem. If water preponderated in it, cold ought to solidify it; if earth preponderated, then fire ought to do so. Actually neither solidifies, but both thicken it. The reason is that it is full of air (hence it floats on the top of water, since air tends to rise). Cold thickens it by turning the air in it into water, for any mixture of oil and water is thicker than either. Fire and the lapse of time thicken and whiten it. The whitening follows on the evaporation of any water that may have been in it; the is due to the change of the air into water as the heat in the oil is dissipated. The effect in both cases is the same and the cause is the same, but the manner of its operation is different. Both heat and cold thicken it, but neither dries it (neither the sun nor cold dries oil), not only because it is glutinous but because it contains air. Its glutinous nature prevents it from giving off vapour and so fire does not dry it or boil it off.
ὅσα δὲ μεικτὰ ὕδατος καὶ γῆς, κατὰ τὸ πλῆθος ἑκατέρου ἄξιον λέγεσθαι οἶνος γάρ τις καὶ πήγνυται καὶ ἕψεται, οἷον τὸ γλεῦκος. ἀπέρχεται δὲ ἀπὸ πάντων τῶν τοιούτων ξηραινομένων τὸ ὕδωρ. σημεῖον δ' ὅτι τὸ ὕδωρ ἡ γὰρ ἀτμὶς συνίσταται εἰς ὕδωρ, ἐάν τις βούληται συλλέγειν ὥστε ὅσοις λείπεταί τι, τοῦτο γῆς. ἔνια δὲ τούτων καὶ ὑπὸ ψυχροῦ, ὥσπερ εἴρηται, παχύνεται καὶ ξηραίνεται τὸ γὰρ ψυχρὸν οὐ μόνον πήγνυσιν, ἀλλὰ ξηραίνει μὲν ὕδωρ, παχύνει δὲ τὸν ἀέρα ὕδωρ ποιοῦν ἡ δὲ πῆξις εἴρηται ξηρασία τις οὖσα. ὅσα μὲν οὖν μὴ παχύνεται ὑπὸ τοῦ ψυχροῦ ἀλλὰ πήγνυται, ὕδατός ἐστι μᾶλλον, οἷον οἶνος καὶ οὖρον καὶ ὄξος καὶ κονία καὶ ὀρός ὅσα δὲ παχύνεται μὴ ἐξατμίζοντα ὑπὸ πυρός, τὰ μὲν γῆς, τὰ δὲ κοινὰ ὕδατος καὶ ἀέρος, μέλι μὲν γῆς, ἔλαιον δ' ἀέρος. ἔστιν δὲ καὶ τὸ γάλα καὶ τὸ αἷμα ἀμφοῖν μὲν κοινὰ καὶ ὕδατος καὶ γῆς, μᾶλλον δὲ τὰ πολλὰ γῆς, ὥσπερ καὶ ἐξ ὅσων ὑγρῶν νίτρον γίγνεται καὶ ἅλες (καὶ λίθοι δ' ἔκ τινων συνίστανται τοιούτων). διὸ ἐὰν μὴ χωρισθῇ ὁ ὀρός, ἐκκάεται ὑπὸ τοῦ πυρὸς ἑψόμενος. τὸ δὲ γεῶδες συνίσταται καὶ ὑπὸ τοῦ ὀποῦ, ἐάν πως ἕψῃ τις, οἷον οἱ ἰατροὶ ὀπίζοντες. οὕτω δὲ χωρίζεται ὁ ὀρὸς καὶ ὁ τυρός. ὁ δὲ χωρισθεὶς ὀρὸς οὐκέτι παχύνεται, ἀλλ' ἐκκάεται ὥσπερ ὕδωρ. εἰ δέ τι μὴ ἔχει τυρὸν γάλα ἢ ὀλίγον, τοῦτο μᾶλλον ὕδατος καὶ ἄτροφον. καὶ τὸ αἷμα δὲ ὁμοίως πήγνυται γὰρ τῷ ξηραίνεσθαι ψυχόμενον. ὅσα δὲ μὴ πήγνυται, οἷον τὸ τῆς ἐλάφου, τὰ τοιαῦτα ὕδατος μᾶλλον, καὶ ψυχρὰ ταῦτα. διὸ καὶ οὐκ ἔχει ἶνας αἱ γὰρ ἶνές εἰσιν γῆς καὶ στερεόν ὥστε καὶ ἐξαιρεθεισῶν οὐ πήγνυται τοῦτο δ' ἐστὶν ὅτι οὐ ξηραίνεται ὕδωρ γὰρ τὸ λοιπόν, ὡς τὸ γάλα τοῦ τυροῦ ἐξαιρεθέντος. σημεῖον δέ τὰ νοσώδη γὰρ αἵματα οὐ θέλει πήγνυσθαι ἰχωροειδῆ γάρ, τοῦτο δὲ φλέγμα καὶ ὕδωρ διὰ τὸ ἄπεπτον εἶναι καὶ ἀκράτητον ὑπὸ τῆς φύσεως.	Those bodies which are made up of earth and water may be classified according to the preponderance of either. There is a kind of wine, for instance, which both solidifies and thickens by boiling—I mean, must. All bodies of this kind lose their water as they That it is their water may be seen from the fact that the vapour from them condenses into water when collected. So wherever some sediment is left this is of the nature of earth. Some of these bodies, as we have said, are also thickened and dried by cold. For cold not only solidifies but also dries water, and thickens things by turning air into water. (Solidifying, as we have said, is a form of drying.) Now those things that are not thickened by cold, but solidified, belong rather to water, e.g.. wine, urine, vinegar, lye, whey. But those things that are thickened (not by evaporation due to fire) are made up either of earth or of water and air: honey of earth, while oil contains air. Milk and blood, too, are made up of both water and earth, though earth generally predominates in them. So, too, are the liquids out of which natron and salt are formed; and stones are also formed from some mixtures of this kind. Hence, if the whey has not been separated, it burns away if you boil it over a fire. But the earthy element in milk can also be coagulated by the help of fig-juice, if you boil it in a certain way as doctors do when they treat it with fig-juice, and this is how the whey and the cheese are commonly separated. Whey, once separated, does not thicken, as the milk did, but boils away like water. Sometimes, however, there is little or no cheese in milk, and such milk is not nutritive and is more like water. The case of blood is similar: cold dries and so solidifies it. Those kinds of blood that do not solidify, like that of the stag, belong rather to water and are very cold. Hence they contain no fibres: for the fibres are of earth and solid, and blood from which they have been removed does not solidify. This is because it cannot dry; for what remains is water, just as what remains of milk when cheese has been removed is water. The fact that diseased blood will not solidify is evidence of the same thing, for such blood is of the nature of serum and that is phlegm and water, the nature of the animal having failed to get the better of it and digest it.
ἔτι δὲ τὰ μὲν λυτά ἐστιν, οἷον νίτρον, τὰ δὲ ἄλυτα, οἷον (384b.) κέραμος, καὶ τούτων τὰ μὲν μαλακτά, οἷον κέρας, τὰ δὲ ἀμάλακτα, οἷον κέραμος καὶ λίθος. αἴτιον δ' ὅτι τἀναντία τῶν ἐναντίων αἴτια, ὥστ' εἰ πήγνυται δυοῖν, ψυχρῷ καὶ ξηρῷ, λύεσθαι ἀνάγκη θερμῷ καὶ ὑγρῷ διὸ πυρὶ καὶ ὕδατι (ταῦτα γὰρ ἐναντία), ὕδατι μὲν ὅσα πυρὶ μόνῳ, πυρὶ δὲ ὅσα ψυχρῷ μόνῳ ὥστ' εἴ τι ὑπ' ἀμφοῖν συμβαίνει πήγνυσθαι, ταῦτα ἄλυτα μάλιστα. γίγνεται δὲ τοιαῦτα ὅσα θερμανθέντα ἔπειτα τῷ ψυχρῷ πήγνυται συμβαίνει γάρ, ὅταν τὸ θερμὸν ἐξικμάσῃ ἐξιόν, τὸ πλεῖστον ὑγρὸν συνθλίβεσθαι πάλιν ὑπὸ τοῦ ψυχροῦ, ὥστε μηδὲ ὑγρῷ διδόναι δίοδον. καὶ διὰ ταῦτα οὔτε τὸ θερμὸν λύει ὅσα γὰρ ὑπὸ ψυχροῦ πήγνυται μόνου, ταῦτα λύει οὔθ' ὑπὸ ὕδατος ὅσα γὰρ ὑπὸ ψυχροῦ πήγνυται, οὐ λύει, ἀλλ' ὅσα ὑπὸ θερμοῦ ξηροῦ μόνον. ὁ δὲ σίδηρος τακεὶς ὑπὸ θερμοῦ ψυχθεὶς πήγνυται. τὰ δὲ ξύλα ἐστὶν γῆς καὶ ἀέρος διὸ καυστὰ καὶ οὐ τηκτὰ οὐδὲ μαλακτά, καὶ ἐπὶ τῷ ὕδατι ἐπιπλεῖ, πλὴν ἐβένου αὕτη δ' οὔ τὰ μὲν γὰρ ἄλλα ἀέρος ἔχει πλέον, ἐκ δὲ τῆς ἐβένου τῆς μελαίνης διαπέπνευκεν ὁ ἀήρ, καὶ ἔστι πλέον ἐν αὐτῇ γῆς. κέραμος δὲ γῆς μόνον διὰ τὸ ξηραινόμενος παγῆναι κατὰ μικρόν οὔτε γὰρ τὸ ὕδωρ εἰσόδους ἔχει, δι' ὧν μόνον πνεῦμα ἐξῆλθεν, οὔτε πῦρ ἔπηξε γὰρ αὐτό. τί μὲν οὖν ἐστι πῆξις καὶ τῆξις, καὶ διὰ πόσα καὶ ἐν πόσοις ἐστίν, εἴρηται.	Some of these bodies are soluble, e.g. natron, some insoluble, e.g. pottery: of the latter, some, like horn, can be softened by heat, others, like pottery and stone, cannot. The reason is that opposite causes have opposite effects: consequently, if solidification is due to two causes, the cold and the dry, solution must be due to the hot and the moist, that is, to fire and to water (these being opposites): water dissolving what was solidified by fire alone, fire what was solidified by cold alone. Consequently, if any things happen to be solidified by the action of both, these are least apt to be soluble. Such a case we find where things have been heated and are then solidified by cold. When the heat in leaving them has caused most of the moisture to evaporate, the cold so compacts these bodies together again as to leave no entrance even for moisture. Therefore heat does not dissolve them (for it only dissolves those bodies that are solidified by cold alone), nor does water (for it does not dissolve what cold solidifies, but only what is solidified by dry heat). But iron is melted by heat and solidified by cold. Wood consists of earth and air and is therefore combustible but cannot be melted or softened by heat. (For the same reason it floats in water—all except ebony. This does not, for other kinds of wood contain a preponderance of air, but in black ebony the air has escaped and so earth preponderates in it.) Pottery consists of earth alone because it solidified gradually in the process of drying. Water cannot get into it, for the pores were only large enough to admit of vapour escaping: and seeing that fire solidified it, that cannot dissolve it either. So solidification and melting, their causes, and the kinds of subjects in which they occur have been described.

Prosequitur de coagulabili et liquefactibili, et dicit quod omnia quae coagulantur, aut sunt aqua, aut composita ex aqua et terra: haec autem omnia coagulantur aut a calido, aut a frigido, aut a sicco. Et hoc ipse probat: quia contrariorum effectuum per se sunt contrariae causae; sed coagulata dissolvuntur aut a frigido, aut a calido, ut patet; quae ergo dissolvuntur a frigido, coagulantur a calido, et e converso: quia dissolutio et coagulatio sunt effectus per se contrarii. Sed videtur quod quaedam coagulentur ab humido: quia mel elixatum coagulatur in aqua, ergo videtur coagulari ab humido. Dicendum quod ab humido ut sic nihil coagulari potest effective: primo quia humidum est materia coagulationis, idem autem non potest esse eidem materia et efficiens; secundo quia in motu coagulationis humidum est terminus a quo: humidum enim superfluum expellitur, et reliquum terminatur cum sicco, et sic fit coagulatio. Sed mel elixatum coagulatur ab aqua calida, non inquantum est humida, sed inquantum est frigida, non actu, sed virtute. Vel potest etiam dici quod mel coagulatur ab aqua calida inquantum est calida, si mel praesupponatur esse terreum a praedominio. Quaecumque igitur sunt aquea, non coagulantur ab igne, idest a calido. Quod probat: quia talia dissolvuntur ab igne, ut patet in glacie; igitur non coagulantur ab igne, scilicet a calido, quia idem eidem non potest esse causa contrariorum. Quod igitur in abscessu calidi et ingressu frigoris coagulatur, dissolvetur e converso in ingressu caloris et abscessu frigoris. Et propter hoc talia aquea non ingrossantur cum coagulantur: quia ingrossatio fit per separationem humidi superflui, quo separato reliquum humidum constat et terminatur cum sicco, et sic sequitur ingrossatio; sed aquea siccum non habent quod separari possit. Quaecumque autem sunt terrea, coagulantur a calido, sicut sal et lac etc.: quod patet, quia talia solvuntur ab aqua. Si autem sint aliqua, quae sint proportionabiliter commixta ex utroque, talia coagulantur ab utroque, sicut lutum: quando enim sunt humida, et magis praedominatur aqua, coagulantur a frigido, quando autem praedominatur terreum, tunc coagulantur a sicco calido ignis. Sed tamen ista coagulatio diversimode fit a calido et a frigido: nam calidum extrinsecum coagulat educendo humidum intrinsecum, ut patet in ovo decocto; frigidum vero extrinsecum expellit calidum intrinsecum, quod secum educit humidum intrinsecum, et sic desiccat et coagulat. Dicit autem quod sunt quaedam, quae non coagulantur in principio a calido, sicut lateres primo indurati a frigore, et postea positi in igne: nam cum ponuntur in igne, fit separatio humidi indurati, postea finaliter desiccantur per separationem humidi superflui. Et propter hoc multi lateres corrumpuntur in fornacibus propter nimiam appropinquationem vel remotionem ab igne: quia tunc aut parum separatur de humiditate, et non sunt decocti, aut separatur nimis ex ea, et de facili franguntur.

Deinde cum dicit: quaecumque quidem etc., determinat de liquabili. Et dicit quod quaecumque coagulantur a frigido, sive sint aquea, sive mixta ex aqua et terra, etiam si habeant in sui compositione plus terrae quam aquae, secundum quantitatem, non secundum proportionem virtutis, talia liquantur a calido. Sed ista sunt in duplici differentia: quaedam enim coagulantur a frigido non educente totum humidum superfluum cum calido intrinseco, et ista solvuntur de facili a calido, sicut lutum et glacies, et huiusmodi; quaedam autem coagulantur a frigido educente totum humidum superfluum cum calido intrinseco, et ista non possunt solvi nisi a fortissimo igne: sicut sunt metalla, et maxime duriora, in quibus partes terrestres subtiles sunt optime commixtae cum humidis remanentibus, et cornua, in quibus est humidum viscosum, quod continet siccum ne defluat. Quod autem ita sit quod coagulatio fiat per separationem humidi, et liquatio fiat per separationem sicci terrei, patet triplici signo. Primo, quia ferrum in quo relictum est parum de humiditate, et illa est fortiter commixta cum sicco terrestri, de difficili solvitur, et quando solvitur et fit humidum, purificatur, quia scoria terrestris subsidet in profundo, et separatur. Et ita multoties faciendo artifices faciunt chalybem, quod est ferrum depuratum; sed nolunt depurare ipsum multoties, et facere perfectum chalybem, tum quia nimis de ferro perditur in igne, tum quia multiplicando purificationem, pondus nimis deminuitur, tum etiam, quia melius est ferrum quod est minus purificatum: quia coagulatum quanto pluries dissolvitur, tanto fit durius quando iterum coagulatur, et ideo ferrum minus purificatum est melius, quia facilius ducitur et magis obedit malleo et manibus artificum. Secundum signum est, quia et lapis qui dicitur pyrimachus, liquescit propter eandem causam, ita ut etiam distillet, quia scilicet continue separatur siccum terrestre. Tertium est, quod plumbum quod in sua natura multum habet de opaco terrae, et ideo est nigrum, quando liquatur eadem causa efficitur coloris albi ad modum calcis, quia in liquatione separatur siccum terrestre, et humidum aereum supernatat secundum superficiem planam, et recipitur lux ubique, et ita recipit album colorem.

Deinde cum dicit: quaecumque autem etc., ostendit quae sint incoagulabilia et illiquefactibilia. Et dicit quod omnia quae coagulantur a sicco calido, sunt in duplici differentia: quaedam enim prius desiccantur a calido sicco per humidi superflui eductionem, et postea ultimo congelantur a frigido per fortem terminationem humidi cum sicco, ut lapides et dentes molares: et ista sunt insolubilia; quaedam autem coagulantur absolute a calido ignis, ut nitrum et sal: et talia liquantur ab aqua frigida et humida. Et huius ratio est, quae supra dicta est, quia contrariorum effectuum sunt contrariae causae: si igitur calidum coagulavit, frigidum solvet. Universaliter itaque coagulantur ea quae sunt terrea vel aquea a praedominio: aquea coagulantur a frigido, sicut glacies, terrea autem coagulantur a calido, ut nitrum, sales, lapides et lateres: propter quod talia sunt magis terrea, quod eorum salsedo ostendit. Quae autem sunt aerea a praedominio, non possunt coagulari neque liquefieri, ut argentum vivum et oleum, quod non coagulatur neque a frigido neque a calido, tum propter suam viscositatem, tum etiam quia est naturae aereae, cuius humiditas de difficili desiccatur. Et propter hoc oleum supernatat super aquam, quia aer naturaliter fertur sursum. Ingrossatur itaque ab ambobus, scilicet calido et frigido, sed a neutro coagulatur. Ingrossatur etiam oleum et albescit, si duret per longum tempus et fiat antiquum: ingrossatur quidem, quia recedente calido intrinseco aer convertitur in elementum grossius, scilicet aqueum, albescit autem, quia evaporat aqueum et terreum quod inerat prius. Aerea etiam liquari non possunt. Cuius ratio est, quia sicut humidum aqueum defluendo intra se facit fluere partes terrae, et mollificat et liquefacit eas, ita humidum aereum e converso adunat siccum terreum et continet intra. Unde ligna propter hanc causam non liquantur. Quod autem ligna sint aerea a praedominio patet, tum quia sunt materia ignis, ut oleum, tum quia supernatant in aqua, praeter ebenum quod est magis terrestre, quod nigredo eius et pondus ostendit.

Deinde cum dicit: quaecumque autem mixta etc., determinat de ingrossabili et non ingrossabili. Et dicit quod ab igne ingrossantur ea, quae habent in sui compositione plus terrae quam aquae, ut lac et sanguis, et quoddam vinum grossum et calidum, in quo siccum terreum et humidum aqueum sunt proportionaliter commixta, sicut est vinum Cretense. Abscedit autem ab his omnibus aqua dum ingrossantur, quia ingrossatio est quaedam desiccatio imperfecta. In cuius signum a tali vino dum decoquitur et ingrossatur ab igne, evaporat humidum aqueum subtile valde: quod si recolligatur in vase tortuoso ad modum stillae, fit aqua, quae dicitur aqua vitis. Quod ergo relinquitur in tali ingrossato, est magis terreum: nam ingrossatio fit per separationem humidi superflui, et terminationem humidi derelicti cum sicco. Et ideo omnia aquea a praedominio impinguari et ingrossari non possunt, ut vinum, universaliter serum et cetera similia. Quod autem lac et sanguis sint terrea a praedominio apparet. De lacte quidem, quia si non separetur serum, et coquatur in igne, exuritur serum, et id quod restat, constat et ingrossatur et efficitur stypticum valde, et valet contra fluxum ventris: quod etiam potest esse signum quod ingrossatio fit per separationem aquei, quia serum est aqueae naturae, substantia autem caseata est magis terrea. Si autem lac non habeat substantiam caseatam, tunc ingrossari non potest et non est aptum ad esum, sicut lac cameli, suis et asinae: et tale est aqueum a praedominio. Et propter hoc artifices ultra substantiam caseatam lactis apponunt coagulum, quando volunt ingrossare ipsum: quod est etiam magis terreum. De sanguine etiam apparet, quia repositus desiccatur propter paucitatem humidi aquei, et habet quosdam magnos poros propter partes terrestres restringentes se, et continentes humidum ne fluat ad centrum. Si autem sanguis sit indigestus propter frigiditatem complexionis, tunc non desiccatur repositus, nec habet poros, quia partes humidae praedominantur et fluunt undique: sed magis est languorosus et fluidus ad modum humoris phlegmatici. Et ex hoc sanguis humanus extractus ex venis si non desiccatur, est signum malae dispositionis et infirmitatis, sicut in venis existens si congeletur, est signum eiusdem, quia significat, quod caliditas naturalis est debilis in tali patiente. Quaedam autem ingrossantur etiam a frigido, ut aerea, sicut oleum. Frigidum enim non solum ingrossat, sed etiam desiccat et coagulat, sicut dictum est: desiccat enim aquam, ut in glacie apparet, ingrossat autem aerem, et convertit in aquam, sicut patet in oleo. Frigus enim aerem existentem in poris convertit in aquam et ingrossat oleum; calor vero intrinsecus facit evaporare humidum aqueum ipsum subtiliando, reliquum terminat cum sicco. Et ideo albescit oleum perspicuo subtiliato.

Deinde cum dicit: adhuc autem haec etc., agit de mollificabili et non mollificabili. Mollificatio enim est quaedam via ad liquefactionem, sicut ingrossatio est via ad coagulationem, sive coagulatio imperfecta. Et dicit quod mollificabilia sunt, quae coagulantur sive etiam ingrossantur a calido tantum, vel a frigido tantum: nam quae coagulantur a calido tantum, solvuntur sive mollificantur a frigido, quae autem coagulantur sive ingrossantur a frigido, solvuntur et mollificari possunt a calido, quia contrariorum contrariae sunt causae, sicut dictum est. Sed quae coagulantur ab ambobus, scilicet a calido et frigido, haec sunt maxime insolubilia: sicut sunt lapides et lateres, quae primo desiccantur a calido per humidi abstractionem, et postea coagulantur a frigido, terminante reliquum humidum cum sicco. Et huius ratio est, quia cum sit coagulatum tam a calido quam a frigido, a neutro dissolvi potest: contrariorum enim effectuum non potest esse eadem causa, sed ut supra dictum est, debet esse contraria. Et propter hanc causam ferrum, quod primo liquefit a calido et magis purificatur, deinde a frigido coagulante induratur, non mollificatur, licet a forti calido liquefiat. Ligna autem et etiam lateres non mollificantur neque liquescunt propter causam superius assignatam, et inferius etiam melius declarandam, quia de mollificabili iterum magis in speciali tractabit; sed de coagulatione et liquefactione, de ingrossatione, et de mollificabili, inquantum mollificatio est via ad liquefactionem, dictum est in superioribus.

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Lectio 10

8	8
ἐκ δὲ τούτων φανερὸν ὅτι ὑπὸ θερμοῦ καὶ ψυχροῦ συνίσταται τὰ σώματα, ταῦτα δὲ παχύνοντα καὶ πηγνύντα ποιεῖται τὴν ἐργασίαν αὐτῶν. διὰ δὲ τὸ ὑπὸ τούτων δημιουργεῖσθαι ἐν ἅπασιν ἔνεστι θερμότης, τισὶ δὲ καὶ ψυχρότης ᾗ ἐκλείπει. ὥστ' ἐπεὶ ταῦτα μὲν ὑπάρχει διὰ τὸ ποιεῖν, ὑγρὸν δὲ καὶ ξηρὸν διὰ τὸ πάσχειν, μετέχει αὐτῶν τὰ κοινὰ πάντων. ἐκ μὲν οὖν ὕδατος καὶ γῆς τὰ ὁμοιομερῆ σώματα συνίσταται, καὶ ἐν φυτοῖς καὶ ἐν ζῴοις, καὶ τὰ μεταλλευόμενα, οἷον χρυσὸς καὶ ἄργυρος καὶ ὅσα ἄλλα τοιαῦτα, ἐξ αὐτῶν τε καὶ ἐκ τῆς ἀναθυμιάσεως τῆς ἑκατέρου ἐγκατακλειομένης, ὥσπερ εἴρηται ἐν ἄλλοις.	All this makes it clear that bodies are formed by heat and cold and that these agents operate by thickening and solidifying. It is because these qualities fashion bodies that we find heat in all of them, and in some cold in so far as heat is absent. These qualities, then, are present as active, and the moist and the dry as passive, and consequently all four are found in mixed bodies. So water and earth are the constituents of homogeneous bodies both in plants and in animals and of metals such as gold, silver, and the rest—water and earth and their respective exhalations shut up in the compound bodies, as we have explained elsewhere.
ταῦτα (385a.) δὲ διαφέρει ἀλλήλων τοῖς τε πρὸς τὰς αἰσθήσεις ἰδίοις ἅπαντα, τῷ ποιεῖν τι δύνασθαι (λευκὸν γὰρ καὶ εὐῶδες καὶ ψοφητικὸν καὶ γλυκὺ καὶ θερμὸν καὶ ψυχρὸν τῷ ποιεῖν τι δύνασθαι τὴν αἴσθησίν ἐστι), καὶ ἄλλοις οἰκειοτέροις πάθεσιν, ὅσα τῷ πάσχειν λέγονται, λέγω δ' οἷον τὸ τηκτὸν καὶ πηκτὸν καὶ καμπτὸν καὶ ὅσα ἄλλα τοιαῦτα πάντα γὰρ τὰ τοιαῦτα παθητικά, ὥσπερ τὸ ὑγρὸν καὶ τὸ ξηρόν. τούτοις δ' ἤδη διαφέρει ὀστοῦν καὶ σὰρξ καὶ νεῦρον καὶ ξύλον καὶ φλοιὸς καὶ λίθος καὶ τῶν ἄλλων ἕκαστον τῶν ὁμοιομερῶν μὲν φυσικῶν δὲ σωμάτων. εἴπωμεν δὲ πρῶτον τὸν ἀριθμὸν αὐτῶν, ὅσα κατὰ δύναμιν καὶ ἀδυναμίαν λέγεται. ἔστιν δὲ τάδε, πηκτὸν ἄπηκτον, τηκτὸν ἄτηκτον, μαλακτὸν ἀμάλακτον, τεγκτὸν ἄτεγκτον, καμπτὸν ἄκαμπτον, κατακτὸν ἀκάτακτον, θραυστὸν ἄθραυστον, θλαστὸν ἄθλαστον, πλαστὸν ἄπλαστον, πιεστὸν ἀπίεστον, ἑλκτὸν ἄνελκτον, ἐλατὸν ἀνήλατον, σχιστὸν ἄσχιστον, τμητὸν ἄτμητον, γλίσχρον ψαθυρόν, πιλητὸν ἀπίλητον, καυστὸν ἄκαυστον, θυμιατὸν ἀθυμίατον. τὰ μὲν οὖν πλεῖστα σχεδὸν τῶν σωμάτων τούτοις διαφέρει τοῖς πάθεσιν τίνα δ' ἕκαστον τούτων ἔχει δύναμιν, εἴπωμεν. περὶ μὲν οὖν πηκτοῦ καὶ ἀπήκτου καὶ τηκτοῦ καὶ ἀτήκτου εἴρηται μὲν καθόλου πρότερον, ὅμως δ' ἐπανέλθωμεν καὶ νῦν. τῶν γὰρ σωμάτων ὅσα πήγνυται καὶ σκληρύνεται, τὰ μὲν ὑπὸ θερμοῦ πάσχει τοῦτο τὰ δ' ὑπὸ ψυχροῦ, ὑπὸ μὲν τοῦ θερμοῦ ξηραίνοντος τὸ ὑγρόν, ὑπὸ δὲ τοῦ ψυχροῦ ἐκθλίβοντος τὸ θερμόν. ὥστε τὰ μὲν ὑγροῦ ἀπουσίᾳ τὰ δὲ θερμοῦ τοῦτο πάσχει, ὅσα μὲν ὕδατος, θερμοῦ, ὅσα δὲ γῆς, ὑγροῦ. τὰ μὲν οὖν ὑγροῦ ἀπουσίᾳ ὑπὸ ὑγροῦ διατήκεται, ἂν μὴ οὕτως συνέλθῃ ὥστε ἐλάττους τοὺς πόρους λειφθῆναι τῶν τοῦ ὕδατος ὄγκων, οἷον ὁ κέραμος ὅσα δὲ μὴ οὕτω, πάντα ὑγρῷ τήκεται, οἷον νίτρον, ἅλες, γῆ ἡ ἐκ πηλοῦ τὰ δὲ θερμοῦ στερήσει ὑπὸ θερμοῦ τήκεται, οἷον κρύσταλλος, μόλυβδος, χαλκός. ποῖα μὲν οὖν πηκτὰ καὶ τηκτά, εἴρηται, καὶ ποῖα (385b.) ἄτηκτα.	All these mixed bodies are distinguished from one another, firstly by the qualities special to the various senses, that is, by their capacities of action. (For a thing is white, fragrant, sonant, sweet, hot, cold in virtue of a power of acting on sense). Secondly by other more characteristic affections which express their aptitude to be affected: I mean, for instance, the aptitude to melt or solidify or bend and so forth, all these qualities, like moist and dry, being passive. These are the qualities that differentiate bone, flesh, sinew, wood, bark, stone and all other homogeneous natural bodies. Let us begin by enumerating these qualities expressing the aptitude or inaptitude of a thing to be affected in a certain way. They are as follows: to be apt or inapt to solidify, melt, be softened by heat, be softened by water, bend, break, be comminuted, impressed, moulded, squeezed; to be tractile or non-tractile, malleable or non-malleable, to be fissile or non-fissile, apt or inapt to be cut; to be viscous or friable, compressible or incompressible, combustible or incombustible; to be apt or inapt to give off fumes. These affections differentiate most bodies from one another. Let us go on to explain the nature of each of them. We have already given a general account of that which is apt or inapt to solidify or to melt, but let us return to them again now. Of all the bodies that admit of solidification and hardening, some are brought into this state by heat, others by cold. Heat does this by drying up their moisture, cold by driving out their heat. Consequently some bodies are affected in this way by defect of moisture, some by defect of heat: watery bodies by defect of heat, earthy bodies of moisture. Now those bodies that are so affected by defect of moisture are dissolved by water, unless like pottery they have so contracted that their pores are too small for the particles of water to enter. All those bodies in which this is not the case are dissolved by water, e.g. natron, salt, dry mud. Those bodies that solidified through defect of heat are melted by heat, e.g. ice, lead, copper. So much for the bodies that admit of solidification and of melting, and those that do not admit of melting.
ἄπηκτα δὲ ὅσα μὴ ἔχει ὑγρότητα ὑδατώδη, μηδὲ ὕδατός ἐστιν, ἀλλὰ πλέον θερμοῦ καὶ γῆς, οἷον μέλι καὶ γλεῦκος (ὥσπερ ζέοντα γάρ ἐστιν), καὶ ὅσα ὕδατος μὲν ἔχει, ἔστιν δὲ πλέον ἀέρος, ὥσπερ τὸ ἔλαιον καὶ ὁ ἄργυρος ὁ χυτός, καὶ εἴ τι γλίσχρον, οἷον <�πίττα καὶ> ἰξός.	The bodies which do not admit of solidification are those which contain no aqueous moisture and are not watery, but in which heat and earth preponderate, like honey and must (for these are in a sort of state of effervescence), and those which do possess some water but have a preponderance of air, like oil and quicksilver, and all viscous substances such as pitch and birdlime.

Postquam philosophus determinavit de principalibus speciebus qualitatum passivarum consequentibus primo primas qualitates passivas, scilicet de coagulabili et non coagulabili, de liquabili et illiquabili, et de ingrossabili et mollificabili, inquantum sunt quasi via ad coagulationem vel liquefactionem, nunc determinat de aliis speciebus minus principalibus. Et circa hoc duo facit. Primo quasi corollarie concludit quoddam superius determinatum, et dicit quod ex dictis est manifestum, quod corpora scilicet inferiora constant et coagulantur a calido et frigido. Et propter hoc corpora ingrossantia et coagulantia, scilicet corpora calida et frigida, faciunt operationem calidi et frigidi, quasi ab eis constituta sint in esse, scilicet activo. Propter hoc etiam in omnibus talibus corporibus est caliditas, quae est magis activa, vel ad minus est in eis frigiditas, inquantum deficiunt a caliditate. Alterum enim contrariorum semper est deficiens et imperfectum respectu alterius, ut frigiditas respectu caliditatis. Et ex hoc quod istae sunt primae qualitates activae, humidum autem et siccum sunt primae passivae, ideo haec conveniunt et sunt communia omnibus. Et ideo ex aqua et terra constituta sunt omnia corpora, tam homoeomera quam plantarum et animalium, et metallorum, sicut auri et argenti, et omnium aliorum quae nascuntur ex exhalatione inclusa in utroque, sicut alibi ipse declaravit. Sed differentia est in hoc inter ea, quod operatio primarum duarum, scilicet calidi et frigidi, consistit in agere, et movere sensus: unde dicuntur qualitates sensibiles; album enim, odor, sonus, dulce, et calidum et frigidum, naturaliter habent facere sensationem, et agere in sensum. Alia autem duo et consequentia magis consistunt in pati, ut liquabile, coagulabile, flexibile et alia, quibus differunt multa corpora naturalia, sicut os, caro, nervus et cetera. Et de his nunc est agendum, quia aliae dictae qualitates activae in aliis declaratae sunt. Quae autem et quot sint istae de quibus est agendum, est clarum in littera.

Secundo ibi: de coagulabili quidem igitur etc., dicit quod de coagulabili et non coagulabili, liquabili et non liquabili dictum est prius universaliter; sed tamen propter maiorem claritatem tam dictorum quam dicendorum dicamus iterum, quod coagulatorum quaedam coagulantur a calido, quaedam a frigido: calidum quidem coagulat, quia exprimit humidum superfluum, frigidum vero, quia expellit calidum, quod secum evaporare facit humidum. Quae igitur coagulantur a calido per absentiam humidi, solvuntur a frigido, quod humidum iterum ingredi facit: quae autem coagulantur a frigido per expulsionem calidi, solvuntur a calido iterum ingrediente, sicut glacies et cetera. Aliqua autem non solvuntur a frigido, quae sunt coagulata a calido: quia coagulatio fuit fortis, et pori relicti sunt parvi, adeo ut humiditas dissolutiva ingredi non possit, sicut sunt lateres. Incoagulabilia autem sunt quae non habent humiditatem aquosam, sed sunt magis terrea, ut mel et mustum: et ratio est, quia talia sunt vehementer calida, et talis caliditas fortiter resistit, et continet humidum intra; et quae sunt aerea a praedominio, sicut oleum, argentum vivum, et viscosa, ut colla.

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Lectio 11

9	9
μαλακτὰ δ' ἐστὶ τῶν πεπηγότων ὅσα μὴ ἐξ ὕδατος, οἷον κρύσταλλος ὕδατος, ἀλλ' ὅσα γῆς μᾶλλον, καὶ μήτ' ἐξίκμασται πᾶν τὸ ὑγρὸν ὥσπερ ἐν νίτρῳ ἢ ἁλσί, μήτ' ἔχει ἀνωμάλως ὥσπερ ὁ κέραμος, ἀλλ' ἢ ἑλκτὰ μὴ ὄντα διαντά, ἢ ἐλατὰ μὴ ὄντα ὕδατος, καὶ μαλακτὰ πυρί, οἷον σίδηρος καὶ κέρας καὶ ξύλα. ἔστι δὲ καὶ τῶν τηκτῶν καὶ τῶν ἀτήκτων τὰ μὲν τεγκτὰ τὰ δὲ ἄτεγκτα, οἷον χαλκὸς ἄτεγκτον, τηκτὸν ὄν, ἔριον δὲ καὶ γῆ τεγκτόν βρέχεται γάρ. καὶ χαλκὸς μὲν δὴ τηκτόν, οὐχ ὑπὸ ὕδατος δὲ τηκτόν. ἀλλὰ καὶ τῶν ὑπὸ ὕδατος τηκτῶν ἔνια ἄτεγκτα, οἷον νίτρον καὶ ἅλες οὐδὲ γὰρ ἄλλο τεγκτὸν οὐδὲν ὃ μὴ μαλακώτερον γίγνεται βρεχόμενον. ἔνια δὲ τεγκτὰ ὄντα οὐ τηκτά ἐστιν, οἷον ἔριον καὶ οἱ καρποί. ἔστι δὲ τεγκτὰ μὲν ὅσα γῆς ὄντα ἔχει τοὺς πόρους μείζους τῶν τοῦ ὕδατος ὄγκων, ὄντων σκληροτέρων τοῦ ὕδατος. τηκτὰ δὲ ὕδατι ὅσα δι' ὅλου. διὰ τί δ' ἡ μὲν γῆ καὶ τήκεται καὶ τέγγεται ὑπὸ τοῦ ὑγροῦ, τὸ δὲ νίτρον τήκεται μέν, τέγγεται δ' οὔ; ὅτι ἐν μὲν τῷ νίτρῳ δι' ὅλου οἱ πόροι, ὥστε διαιρεῖται εὐθὺς ὑπὸ τοῦ ὕδατος τὰ μόρια, ἐν δὲ τῇ γῇ καὶ παραλλάξ εἰσι πόροι, ὥστε ὁποτέρως ἂν δέξηται, διαφέρει τὸ πάθος.	Those bodies admit of softening which are not (like ice) made up of water, but in which earth predominates. All their moisture must not have left them (as in the case of natron and salt), nor must the relation of dry to moist in them be incongruous (as in the case of pottery). They must be tractile (without admitting water) or malleable (without consisting of water), and the agent in softening them is fire. Such are iron and horn. Both of bodies that can melt and of bodies that cannot, some do and some do not admit of softening in water. Copper, for instance, which can be melted, cannot be softened in water, whereas wool and earth can be softened in water, for they can be soaked. (It is true that though copper can be melted the agent in its case is not water, but some of the bodies that can be melted by water too such as natron and salt cannot be softened in water: for nothing is said to be so affected unless the water soaks into it and makes it softer.) Some things, on the other hand, such as wool and grain, can be softened by water though they cannot be melted. Any body that is to be softened by water must be of earth and must have its pores larger than the particles of water, and the pores themselves must be able to resist the action of water, whereas bodies that can be 'melted' by water must have pores throughout. (Why is it that earth is both 'melted' and softened by moisture, while natron is 'melted' but not softened? Because natron is pervaded throughout by pores so that the parts are immediately divided by the water, but earth has also pores which do not connect and is therefore differently affected according as the water enters by one or the other set of pores.)
ἔστι δὲ καὶ τὰ μὲν τῶν σωμάτων καμπτὰ καὶ εὐθυντά, οἷον κάλαμος καὶ λύγος, τὰ δ' ἄκαμπτα τῶν σωμάτων, οἷον κέραμος καὶ λίθος. ἔστιν δὲ ἄκαμπτα μὲν καὶ ἀνεύθυντα ὅσων σωμάτων οὐ δύναται τὸ μῆκος εἰς εὐθύτητα ἐκ περιφερείας καὶ ἐξ εὐθύτητος εἰς περιφέρειαν μεταβάλλειν, καὶ τὸ κάμπτεσθαι καὶ τὸ εὐθύνεσθαί ἐστιν τὸ εἰς εὐθύτητα ἢ περιφέρειαν μεθίστασθαι ἢ κινεῖσθαι καὶ γὰρ τὸ ἀνακαμπτόμενον καὶ τὸ (386a.) κατακαμπτόμενον κάμπτεται. ἡ μὲν οὖν εἰς κυρτότητα ἢ κοιλότητα κίνησις τοῦ μήκους σῳζομένου κάμψις ἐστίν εἰ γὰρ καὶ εἰς τὸ εὐθύ, εἴη ἂν ἅμα κεκαμμένον καὶ εὐθύ ὅπερ ἀδύνατον, τὸ εὐθὺ κεκάμφθαι. καὶ εἰ κάμπτεται πᾶν ἢ ἀνακάμψει ἢ κατακάμψει, τούτων δὲ τὸ μὲν εἰς τὸ κυρτὸν τὸ δ' εἰς τὸ κοῖλον μετάβασις, οὐκ ἂν εἴη καὶ εἰς τὸ εὐθὺ κάμψις, ἀλλ' ἔστι κάμψις καὶ εὔθυνσις ἄλλο καὶ ἄλλο. καὶ ταῦτά ἐστιν καμπτὰ καὶ εὐθυντά, καὶ ἄκαμπτα καὶ ἀνεύθυντα.	Some bodies can be bent or straightened, like the reed or the withy, some cannot, like pottery and stone. Those bodies are apt to be bent and straightened which can change from being curved to being straight and from being straight to being curved, and bending and straightening consist in the change or motion to the straight or to a curve, for a thing is said to be in process of being bent whether it is being made to assume a convex or a concave shape. So bending is defined as motion to the convex or the concave without a change of length. For if we added 'or to the straight', we should have a thing bent and straight at once, and it is impossible for that which is straight to be bent. And if all bending is a bending back or a bending down, the former being a change to the convex, the latter to the concave, a motion that leads to the straight cannot be called bending, but bending and straightening are two different things. These, then, are the things that can, and those that cannot be bent, and be straightened.
καὶ τὰ μὲν κατακτὰ καὶ θραυστὰ ἅμα ἢ χωρίς, οἷον ξύλον μὲν κατακτόν, θραυστὸν δ' οὔ, κρύσταλλος δὲ καὶ λίθος θραυστόν, κατακτὸν δ' οὔ, κέραμος δὲ καὶ θραυστὸν καὶ κατακτόν. διαφέρει δ', ὅτι κάταξις μέν ἐστιν εἰς μεγάλα μέρη διαίρεσις καὶ χώρισις, θραῦσις δὲ εἰς τὰ τυχόντα καὶ πλείω δυοῖν. ὅσα μὲν οὖν οὕτω πέπηγεν ὥστε πολλοὺς ἔχειν παραλλάττοντας πόρους, θραυστά (μέχρι γὰρ τούτου διίσταται), ὅσα δ' εἰς πολύ, κατακτά, ὅσα δ' ἄμφω, ἀμφότερα.καὶ τὰ μὲν θλαστά, οἷον χαλκὸς καὶ κηρός, τὰ δ' ἄθλαστα, οἷον κέραμος καὶ ὕδωρ.	Some things can be both broken and comminuted, others admit only one or the other. Wood, for instance, can be broken but not comminuted, ice and stone can be comminuted but not broken, while pottery may either be comminuted or broken. The distinction is this: breaking is a division and separation into large parts, comminution into parts of any size, but there must be more of them than two. Now those solids that have many pores not communicating with one another are comminuible (for the limit to their subdivision is set by the pores), but those whose pores stretch continuously for a long way are breakable, while those which have pores of both kinds are both comminuible and breakable.

Determinat de mollificabili magis in speciali, et ponit sex conditiones quas habere debet coagulatum ad hoc quod mollificetur. Et prima est, quod tale coagulatum non sit aqua vel aqueum a praedominio, sed si est in eo excessus unius super alterum, sit magis terreum: et propter defectum huius, glacies non est mollificabilis. Secunda conditio est, quod totum humidum non sit evaporatum per coagulationem, quia mollificabile debet esse tam aqueum quam terreum, vel non multum plus terreum: et propter hoc nitrum et sal non sunt mollificabilia, sed statim solvuntur. Tertia conditio est, quod non habeant siccum inaequaliter dispositum, ne pori sint strictiores quam humidum aqueum, quod est quasi materia mollificationis, diffundi possit: et propter hoc lateres et lapides non mollificantur. Quarta vero est, quod non sint trahibilia in longum vel ad latus, ut corrigia et nervus; et ratio est, quia talia sunt viscosa, quae non cedunt tactui in profundum sui, sed extra se trahuntur in longum: mollificabile autem debet cedere tactui in se, sicut manifestum fuit superius in definitione mollis. Quinta est, quod non sint humectabilia, humido scilicet alieno et extrinseco, ut lana, sed mollificabile debet habere humidum proprium: est enim humidi quod ubique fluat, et ita mollificet. Sexta conditio est, quod non sint ductibilia: et ratio est, quia talia habent plus aquae quam terrae, sicut metalla. Si autem sint aliqua quae cum magno labore liquentur et ducantur, et tamen non habeant multum plus aquae quam terrae, immo forte minus, sicut ferrum, talia mollificantur. Fit autem mollificatio tanquam a causa efficiente ut in pluribus ab igne, sicut ligna et cornu mollificantur ab igne.

Deinde cum dicit: sunt autem liquabilium etc., prosequitur de intingibili et non intingibili. Ad cuius evidentiam sciendum est, quod intingibile hic dicitur, quod est susceptivum humidi extrinseci per poros amplos et duros. Ratione primi ea quae sunt aquea, non madefiunt neque intinguntur, quia aquea non habent poros, sicut glacies; metalla autem non intinguntur, quia licet sint porosa, non tamen habent poros amplos sed strictos, ita quod humidum non potest ingredi et madefacere; ratione tertii multa quae liquantur ab aqua, non sunt intingibilia, sicut nitrum et sal, quia licet talia habeant poros amplos, non tamen pori sunt duri sed molles et passibiles, ita quod humidum ingrediens non madefacit sed corrumpit illud in quod intrat. Quae autem habent poros amplos et duros, sicut lana, pannus, et multa alia, intinguntur: quia humidum ingrediens per poros amplos madefacit siccum terrestre, et non corrumpit ipsum propter duritiem. Ex his autem patet quod intingibilia sunt terrea a praedominio, quia in eis dominatur siccum terrestre, et coagulata sunt a calido per abstractionem humidi: ideo intinguntur per novam humidi introductionem. Patet etiam ratio quare terra intingitur, nitrum autem et sal quae sunt terrea, non intinguntur. Primo scilicet quia terra habet poros duriores quam talia, propter maiorem admixtionem humidi fluidi in talibus quam in terra; secundo etiam quia talia sunt porosa per totum, et ex hoc humidum per totum ingrediens et defluens cito dividit ea in partes et corrumpit: terra autem habet poros non per totum, sed hic illic, et ideo partes magis continentur.

Deinde cum dicit: sunt autem et haec quidem etc., ostendit quae sint flexibilia et quae dirigibilia, dicens quod quaedam corpora sunt flexibilia et dirigibilia, ut calamus et virga, quaedam vero non sunt flexibilia neque dirigibilia, sicut lateres et lapides. Ad intelligendum autem quae sint flexibilia et dirigibilia, et quae non, sciendum est quod flexio vel etiam rectificatio, est motus a circulari peripheria in rectitudinem, vel a rectitudine in peripheriam circularem, manente eadem longitudine flexi. Omnia igitur corpora quae possunt moveri ex rectitudine in peripheriam circularem, vel e converso ex peripheria circulari, sive sit concava sive convexa, in rectitudinem, sunt flexibilia vel dirigibilia: quae autem non possunt ita moveri, non sunt flexibilia neque dirigibilia. Non tamen est idem flexio et rectificatio, immo sunt motus contrarii: quia flexio est motus ad concavitatem vel convexitatem, rectificatio autem est motus ad rectitudinem. Sed philosophus hic non assignat causam praedictorum: et ideo sciendum est, quod humidum fluens, sicut superius declaravimus, quaerit terminos alienos, quia non bene terminatur terminis propriis, siccum vero quaerit terminos proprios, quibus bene terminatur. Flexio igitur est motus ad terminos alienos, quia res quando est flexa, non habet proprios terminos suae longitudinis, sed potest amplius elongari si dirigatur: rectificatio vero est motus ad terminos quasi proprios et sibi convenientes secundum suam longitudinem; et ideo res ratione humidi fluentis flectuntur, sed ratione sicci retrahentis habent dirigi et rectificari. Quae igitur sunt coagulata per eductionem humidi, non sunt flexibilia neque dirigibilia, sed potius franguntur, ut lateres et ligna sicca. Quae autem habent humidum viscosum grossum, flectuntur de facili, et semper flectuntur ad illam partem in qua est maior humiditas, sicut tabulae calefactae ad ignem, flectuntur versus ignem, quia ignis calefaciendo eas educit humiditatem ad illam partem. Sed quae habent humidum viscosum magis subtile, et bene commixtum cum sicco aereo subtili, non flectuntur ita de facili: sed tamen flexa cito redeunt ad rectitudinem, sicut boni enses; vel si non possunt redire ad perfectam rectitudinem, redeunt ad illam partem rectitudinis quam habuerunt in sui coagulatione, sicut bonae balistae, et arcus emissa sagitta. Sed quae habent humiditatem grossam, et non bene commixtam cum sicco, non redeunt ad rectitudinem, sicut pravi enses, arcus et similia.

Deinde cum dicit: et haec quidem frangibilia etc., determinat de frangibili et comminuibili, quae sunt passiones procedentes ex eisdem causis, scilicet humido et sicco. Nam quae habent parum aut nihil de sicco, et multum de humido, neque sunt frangibilia neque comminuibilia, sicut liquida. Quae autem habent multum de sicco, sunt in tribus differentiis: quaedam enim sunt frangibilia, et non comminuibilia, ut lignum; quaedam sunt comminuibilia et non frangibilia, sicut lapis, qui a scalpentibus dividitur in partes minutas, non autem frangitur in magnas partes, et paucas numero; quaedam vero sunt comminuibilia et frangibilia, sicut lateres. Et ratio huius differentiae est, quia quaedam ita coagulantur quod habent parvos poros, numero multos, et propinquos situatione, et ista comminuuntur; quia comminutio est divisio in parvas partes, et divisio rei fit in poris ipsius, nisi scindantur: si ergo pori sunt multi, divisio fiet secundum multas partes. Aliqua vero habent poros magnos, paucos numero et distantes situ: et talia sunt frangibilia, quia fractio est divisio rei in magnas partes et paucas. Alia vero habent utrumque, scilicet quosdam poros magnos et reliquos parvos: et talia sunt frangibilia et comminuibilia, sicut lateres. Considerandum est autem ad evidentiam praedictorum, quod porus hic vocatur illa pars rei porosae, quae est non quidem vacua, sicut dicebant antiqui credentes vacuum dari, sed plena corpore subtili, sive tale corpus subtile sit eiusdem naturae cum reliquo, sive alienae, puta aqueae vel aereae.

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Lectio 12

καὶ τὰ μὲν θλαστά, οἷον χαλκὸς καὶ κηρός, τὰ δ' ἄθλαστα, οἷον κέραμος καὶ ὕδωρ. ἔστιν δὲ θλάσις ἐπιπέδου κατὰ μέρος εἰς βάθος μετάστασις ὤσει ἢ πληγῇ, τὸ δ' ὅλον ἁφῇ. ἔστιν δὲ τὰ τοιαῦτα καὶ μαλακτά, οἷον κηρὸς μένοντος τοῦ ἄλλου ἐπιπέδου κατὰ μέρος μεθίσταται, καὶ σκληρά, οἷον χαλκός, καὶ ἄθλαστα καὶ σκληρά, οἷον κέραμος (οὐ γὰρ ὑπείκει εἰς βάθος τὸ ἐπίπεδον), καὶ ὑγρά, οἷον ὕδωρ (τὸ γὰρ ὕδωρ ὑπείκει μέν, ἀλλ' οὐ κατὰ μέρος, ἀλλ' ἀντιμεθίσταται). τῶν δὲ θλαστῶν ὅσα μὲν μένει θλασθέντα καὶ εὔθλαστα χειρί, ταῦτα μὲν πλαστά, τὰ δὲ ἢ μὴ εὔθλαστα, ὥσπερ λίθος ἢ ξύλον, ἢ εὔθλαστα μέν, μὴ μένει δὲ ἡ θλάσις, ὥσπερ ἐρίου ἢ σπόγγου, οὐ πλαστά, ἀλλὰ πιεστὰ ταῦτ' ἐστίν. ἔστι δὲ πιεστὰ ὅσα ὠθούμενα εἰς αὑτὰ συνιέναι δύναται, εἰς βάθος τοῦ ἐπιπέδου παραλλάττοντος, οὐ διαιρουμένου, καὶ <�μὴ> μεθισταμένου ἄλλου ἄλλῳ μορίου, οἷον τὸ ὕδωρ ποιεῖ τοῦτο γὰρ ἀντιμεθίσταται. ἔστι δὲ ὦσις ἡ κίνησις ὑπὸ τοῦ κινοῦντος, ἣ (386b.) γίγνεται ἀπὸ τῆς ἅψεως πληγὴ δέ, ὅταν ἀπὸ τῆς φορᾶς. πιέζεται δὲ ὅσα πόρους ἔχει κενοὺς συγγενοῦς σώματος καὶ πιεστὰ ταῦτα ὅσα δύναται εἰς τὰ ἑαυτῶν κενὰ συνιέναι ἢ εἰς τοὺς ἑαυτῶν πόρους [ἐνίοτε γὰρ οὐ κενοί εἰσιν εἰς οὓς συνέρχεται,] οἷον ὁ βεβρεγμένος σπόγγος (πλήρεις γὰρ αὐτοῦ οἱ πόροι), ἀλλ' ὧν ἂν οἱ πόροι πλήρεις ὦσι μαλακωτέρων ἢ αὐτὸ τὸ πεφυκὸς συνιέναι εἰς αὐτά. πιεστὰ μὲν οὖν ἐστιν οἷον σπόγγος, κηρός, σάρξ ἀπίεστα δὲ τὰ μὴ πεφυκότα συνιέναι ὤσει εἰς τοὺς ἑαυτῶν πόρους διὰ τὸ ἢ μὴ ἔχειν ἢ σκληροτέρων ἔχειν πλήρεις ὁ γὰρ σίδηρος ἀπίεστος καὶ λίθος καὶ ὕδωρ καὶ πᾶν ὑγρόν.	Some things, e.g. copper and wax, are impressible, others, e.g. pottery and water, are not. The process of being impressed is the sinking of a part of the surface of a thing in response to pressure or a blow, in general to contact. Such bodies are either soft, like wax, where part of the surface is depressed while the rest remains, or hard, like copper. Non-impressible bodies are either hard, like pottery (its surface does not give way and sink in), or liquid, like water (for though water does give way it is not in a part of it, for there is a reciprocal change of place of all its parts). Those impressibles that retain the shape impressed on them and are easily moulded by the hand are called 'plastic'; those that are not easily moulded, such as stone or wood, or are easily moulded but do not retain the shape impressed, like wool or a sponge, are not plastic. The last group are said to be 'squeezable'. Things are 'squeezable' when they can contract into themselves under pressure, their surface sinking in without being broken and without the parts interchanging position as happens in the case of water. (We speak of pressure when there is movement and the motor remains in contact with the thing moved, of impact when the movement is due to the local movement of the motor.) Those bodies are subject to squeezing which have empty pores—empty, that is, of the stuff of which the body itself consists—and that can sink upon the void spaces within them, or rather upon their pores. For sometimes the pores upon which a body sinks in are not empty (a wet sponge, for instance, has its pores full). But the pores, if full, must be full of something softer than the body itself which is to contract. Examples of things squeezable are the sponge, wax, flesh. Those things are not squeezable which cannot be made to contract upon their own pores by pressure, either because they have no pores or because their pores are full of something too hard. Thus iron, stone, water and all liquids are incapable of being squeezed.
ἑλκτὰ δ' ἐστὶν ὅσων δυνατὸν εἰς τὸ πλάγιον μεθίστασθαι τὸ ἐπίπεδον τὸ γὰρ ἕλκεσθαί ἐστι τὸ ἐπὶ τὸ κινοῦν μεθίστασθαι τὸ ἐπίπεδον συνεχὲς ὄν. ἔστιν δὲ τὰ μὲν ἑλκτά, οἷον θρίξ, ἱμάς, νεῦρον, σταίς, ἰξός, τὰ δ' ἄνελκτα, οἷον ὕδωρ καὶ λίθος. τὰ μὲν οὖν ταὐτά ἐστιν ἑλκτὰ καὶ πιεστά, οἷον ἔριον, τὰ δ' οὐ ταὐτά, οἷον φλέγμα πιεστὸν μὲν οὐκ ἔστιν, ἑλκτὸν δέ, καὶ ὁ σπόγγος πιεστὸν μέν, οὐχ ἑλκτὸν δέ. ἔστιν δὲ καὶ τὰ μὲν ἐλατά, οἷον χαλκός, τὰ δ' ἀνήλατα, οἷον λίθος καὶ ξύλον. ἔστιν δ' ἐλατὰ μὲν ὅσα τῇ αὐτῇ πληγῇ δύναται ἅμα καὶ εἰς πλάτος καὶ εἰς βάθος τὸ ἐπίπεδον μεθίστασθαι κατὰ μέρος, ἀνήλατα δὲ ὅσα ἀδύνατα. ἔστιν δὲ τὰ μὲν ἐλατὰ ἅπαντα καὶ θλαστά, τὰ δὲ θλαστὰ οὐ πάντα ἐλατά, οἷον ξύλον ὡς μέντοι ἐπίπαν εἰπεῖν, ἀντιστρέφει. τῶν δὲ πιεστῶν τὰ μὲν ἐλατὰ τὰ δ' οὔ, κηρὸς μὲν καὶ πηλὸς ἐλατά, ἔριον δ' οὔ [οὐδ' ὕδωρ]. ἔστιν δὲ καὶ τὰ μὲν σχιστά, οἷον ξύλον, τὰ δὲ ἄσχιστα, οἷον κέραμος. ἔστιν δὲ σχιστὸν τὸ δυνάμενον διαιρεῖσθαι ἐπὶ πλέον ἢ τὸ διαιροῦν διαιρεῖ σχίζεται γάρ, ὅταν ἐπὶ πλέον διαιρῆται ἢ τὸ διαιροῦν διαιρεῖ, καὶ προηγεῖται ἡ διαίρεσις ἐν δὲ τῇ τμήσει οὐκ ἔστιν τοῦτο. ἄσχιστα δὲ ὅσα μὴ δύνανται τοῦτο πάσχειν. ἔστιν δὲ οὔτε μαλακὸν οὐδὲν σχιστόν (λέγω δὲ τῶν ἁπλῶς μαλακῶν καὶ μὴ πρὸς ἄλληλα οὕτω μὲν γὰρ καὶ σίδηρος ἔσται μαλακός) οὔτε τὰ σκληρὰ πάντα, (387a.) ἀλλ' ὅσα μήτε ὑγρά ἐστιν μήτε θλαστὰ μήτε θραυστά τοιαῦτα δ' ἐστὶν ὅσα κατὰ μῆκος ἔχει τοὺς πόρους, καθ' οὓς προσφύεται ἀλλήλοις, ἀλλὰ μὴ κατὰ πλάτος.	Things are tractile when their surface can be made to elongate, for being drawn out is a movement of the surface, remaining unbroken, in the direction of the mover. Some things are tractile, e.g. hair, thongs, sinew, dough, birdlime, and some are not, e.g. water, stone. Some things are both tractile and squeezable, e.g. wool; in other cases the two qualities do not coincide; phlegm, for instance, is tractile but not squeezable, and a sponge squeezable but not tractile. Some things are malleable, like copper. Some are not, like stone and wood. Things are malleable when their surface can be made to move (but only in part) both downwards and sideways with one and the same blow: when this is not possible a body is not malleable. All malleable bodies are impressible, but not all impressible bodies are malleable, e.g. wood, though on the whole the two go together. Of squeezable things some are malleable and some not: wax and mud are malleable, wool is not. Some things are fissile, e.g. wood, some are not, e.g. potter's clay. A thing is fissile when it is apt to divide in advance of the instrument dividing it, for a body is said to split when it divides to a further point than that to which the dividing instrument divides it and the act of division advances: which is not the case with cutting. Those bodies which cannot behave like this are non-fissile. Nothing soft is fissile (by soft I mean absolutely soft and not relatively: for iron itself may be relatively soft); nor are all hard things fissile, but only such as are neither liquid nor impressible nor comminuible. Such are the bodies that have the pores along which they cohere lengthwise and not crosswise.
τμητὰ δ' ἐστὶν τῶν συνεστώτων σκληρῶν ἢ μαλακῶν ὅσα δύναται μήτ' ἐξ ἀνάγκης προηγεῖσθαι τῆς διαιρέσεως μήτε θραύεσθαι διαιρούμενα ὅσα δὲ μὴ ὑγρὰ ᾖ, τὰ τοιαῦτα ἄτμητα. ἔνια δ' ἐστὶν ταὐτὰ καὶ τμητὰ καὶ σχιστά, οἷον ξύλον ἀλλ' ὡς ἐπὶ τὸ πολὺ σχιστὸν μὲν κατὰ τὸ μῆκος, τμητὸν δὲ κατὰ τὸ πλάτος ἐπεὶ γὰρ διαιρεῖται ἕκαστον εἰς πολλά, ᾗ μὲν μήκη πολλὰ τὸ ἕν, σχιστὸν ταύτῃ, ᾗ δὲ πλάτη πολλὰ τὸ ἕν, τμητὸν ταύτῃ. γλίσχρον δ' ἐστὶν ὅταν ἑλκτὸν ᾖ ὑγρὸν ὂν ἢ μαλακόν. τοιοῦτον δὲ γίγνεται τῇ ἐπαλλάξει ὅσα ὥσπερ αἱ ἁλύσεις σύγκεινται τῶν σωμάτων ταῦτα γὰρ ἐπὶ πολὺ δύναται ἐκτείνεσθαι καὶ συνιέναι. ὅσα δὲ μὴ τοιαῦτα, ψαθυρά. πιλητὰ δ' ὅσα τῶν πιεστῶν μόνιμον ἔχει τὴν πίεσιν, ἀπίλητα δὲ ὅσα ἢ ὅλως ἀπίεστα ἢ μὴ μόνιμον ἔχει τὴν πίεσιν. καὶ τὰ μὲν καυστά ἐστιν τὰ δὲ ἄκαυστα, οἷον ξύλον μὲν καυστὸν καὶ ἔριον καὶ ὀστοῦν, λίθος δὲ καὶ κρύσταλλος ἄκαυστον. ἔστιν δὲ καυστὰ ὅσα ἔχει πόρους δεκτικοὺς πυρὸς καὶ ὑγρότητα ἐν τοῖς κατ' εὐθυωρίαν πόροις ἀσθενεστέραν πυρός.	Those hard or soft solids are apt to be cut which do not necessarily either split in advance of the instrument or break into minute fragments when they are being divided. Those that necessarily do so and liquids cannot be cut. Some things can be both split and cut, like wood, though generally it is lengthwise that a thing can be split and crosswise that it can be cut. For, a body being divided into many parts fin so far as its unity is made up of many lengths it is apt to be split, in so far as it is made up of many breadths it is apt to be cut. A thing is viscous when, being moist or soft, it is tractile. Bodies owe this property to the interlocking of their parts when they are composed like chains, for then they can be drawn out to a great length and contracted again. Bodies that are not like this are friable. Bodies are compressible when they are squeezable and retain the shape they have been squeezed into; incompressible when they are either inapt to be squeezed at all or do not retain the shape they have been squeezed into.

Ostendit quae sunt impressibilia et quae non. Et dicit quod sunt quaedam corpora impressibilia, idest apta nata recipere impressionem, quorum quaedam sunt mollia, sicut cera, quaedam vero sunt dura, sicut aes. Alia autem non sunt impressibilia: et horum etiam aliqua sunt mollia, sicut aqua, aliqua autem sunt dura, velut later et lapis. Nam impressio passive sumpta est cessio in profundum secundum partem superficiei, non e contra circumstando (quod dicitur propter aquam, quae cedit imprimenti secundum superficiem, non tamen suscipit impressionem, quia contra circumstat, sicut supra dictum est in definitione mollis). Et ista fit dupliciter: aut per solam pulsionem tactus, ut in cera et in omnibus mollibus, aut per percussionem, ut in metallis et aliis duris. Universaliter igitur eorum quae sunt impressibilia, quaedam sunt mollificabilia sive mollia actu, ut cera, quaedam vero sunt dura, ut metalla: sed tamen talia sunt, in quibus est humiditas fortis et bene permixta cum sicco terrestri. Alia autem dura, in quibus non est fortis humiditas sed est educta a coagulante, et etiam illa debilis quae remansit non est bene commixta cum sicco terrestri, talia non sunt impressibilia, sicut later et lapis. Non est etiam impressibilis aqua, propter rationem superius assignatam, propter quam etiam non est mollis. Manifestum est autem ex dictis, quod humiditas non fluens sed bene permixta cum sicco terrestri, est materia impressionis.

Deinde cum dicit: impressibilium autem etc., determinat de formabili manu et non formabili. Et dicit quod impressibilia sunt duplicia: quaedam enim sunt impressibilia, quae non tantum suscipiunt impressionem de facili, sed etiam retinent eam: et talia sunt etiam formabilia manu, sicut pasta et cera; quaedam vero sunt quae bene retinent impressionem, sed non recipiunt eam de facili, sicut metalla, quae non recipiunt impressionem nisi per fortem percussionem: et talia non sunt formabilia manu, sed tamen formantur per artem, fundendo scilicet ea. Quaedam etiam sunt quae de facili recipiunt impressionem, sed eam non retinent, sicut lana aut spongia: et haec non sunt manu formabilia, ita scilicet quod retineant formationem. Quae autem non sunt impressibilia, non sunt etiam manu formabilia, licet formentur per artem, puta per sculptoriam, sicut lateres et lapides. Ex quibus patet quod materia impressibilium, etiam manu formabilium, est eadem, non differens nisi secundum magis et minus: quia manu formabilia debent esse paulo plus humida quam impressibilia; et ex hoc res fere eodem modo sunt manu formabilia quo sunt impressibilia, scilicet permanenter aut non permanenter.

Deinde cum dicit: sunt autem capibilia etc., agit de capibili et non capibili. Et dicit quod capibilia sunt, quae pulsa possunt convenire, idest contrahi et reverti, intra se in profundum sui, superficie mutata de maiore in minorem, sicut cum stringitur spongia, et non divisa aut translata in aliam partem, sicut accidit in aqua, quae quando comprimitur manibus, quasi effugit ad aliam partem. Et quia multoties in superioribus et nunc in isto loco fecit mentionem de pulsione et percussione, ideo declarat quid sint, et dicit quod pulsio est motus factus per solum tactum, scilicet sine magna violentia: percussio autem est motus factus cum elevatione vel manus vel alterius instrumenti percutientis, sicut quando faber elevat malleum et percutit. Ratio autem quare talia sunt capibilia, est quia habent poros plenos subtiliori corpore, sive tale corpus subtile sit eiusdem naturae cum reliquo, sive alterius. Nam tale corpus subtile aut egreditur quando capitur, si est alterius naturae, sicut patet in spongia, aut ingrossat et comprimitur, si est eiusdem naturae, sicut in carne. Quae igitur habent tales poros, sunt capibilia: quae autem non habent poros, ut aqua et liquida, non capiuntur: quae vero habent poros, sed plenos corpore duro, ut ferrum, illa etiam non sunt capibilia. Ex quibus manifestum est quod capibile hic vocatur, non quodcumque accipi potest, prout nomen sonat, sed quod potest restringi et reduci ad minorem superficiem. Ferrum enim capi, idest accipi, potest manibus: tamen dicit quod non est capibile, quia non potest restringi ad minorem superficiem. Est autem materia capibilium siccum terrestre a praedominio, sicut ex dictis est manifestum.

Deinde cum dicit: trahibilia autem etc., determinat de trahibili. Et dicit quod trahibilia sunt, quorum superficies potest mutari de loco ad locum, sicut corrigia. Est enim tractio motus corporis secundum longitudinem vel latitudinem, ita quod ex illa parte qua movetur, extenditur, ex alia per accidens restringitur: sicut corrigia cum trahitur per longum, extenditur, et restringitur secundum latitudinem. Quaedam autem sunt trahibilia et etiam capibilia, ut cera et lana: aliqua vero sunt trahibilia et non capibilia, ut phlegma et sputa, quae trahuntur ad modum fili: aliqua sunt capibilia et non trahibilia, sicut spongia. Sed quae carent sicco, sicut aqua, vel quae non habent humiditatem viscosam, sicut lapis et metalla, non sunt trahibilia vel extensibilia, neque etiam capibilia. Ex quibus est manifestum quod illa dicuntur universaliter trahibilia, quorum materia est humidum viscosum a praedominio: et tale humidum propter viscositatem continet siccum terrestre. Non dicitur etiam hic trahibile secundum usum vocabuli apud nos: Latini enim grammatici vocant trahibilia, omnia quae possunt moveri de loco ad locum, vel per violentiam, sicut homo dicitur trahi ad carcerem, vel saltem per motum qui non est naturalis talibus, sicut currus et ligna dicuntur trahi. Sed hic vocatur trahibile tantummodo illud, cuius partes mutant locum per extensionem, sicut accidit in corrigia vel pelle molli: quia trahi est transferri de loco ad locum secundum partes manente continuitate totius.

Deinde cum dicit: sunt autem et haec quidem ductilia etc., ostendit quae sint ductilia et quae non. Et dicit quod ductilia sunt ea, quae transferuntur secundum partem superficiei in profundum et ad latus per unam et eandem percussionem, sicut aes, idest species simplices metallorum, ut stannum vel plumbum, quae per unam et eandem percussionem, quando percutiuntur, deprimuntur in profundum secundum partem superficiei, et etiam extenduntur secundum latera: vel etiam deprimuntur et extenduntur secundum totam superficiem, si instrumentum percutiens sit aequale vel maius ipsa superficie. Quae autem non possunt deprimi et extendi, sicut dictum est, talia non sunt ductilia, sicut lapis et lignum. Causa autem quare talia cedunt percutienti in profundum et ad latus, est humiditas bene commixta cum sicco terrestri, quae calefacta et commota per percussionem facit secum fluere aliqualiter siccum terrestre. Et quia tale humidum est valde constrictum et proportionabiliter commixtum cum sicco, non habens magnos poros interceptos, ideo facit siccum fluere ad omnem partem. Ex quo sequitur, quod meliora sunt metalla quae ducuntur aequaliter ab omni parte, quam quae ducuntur ex una parte, ex alia autem crepant vel minus ducuntur, quia in talibus humidum est melius permixtum cum sicco. Dicit autem quod omnia quae sunt ductilia, sunt etiam impressibilia, sed ut est dicere ad omne, idest universaliter loquendo, non convertitur consequentia, quod scilicet omne impressibile sit ductile: quia lignum est impressibile, non tamen est ductile. Similiter capibilium quaedam sunt ductilia sicut cera, quaedam vero non, sicut aqua, quae non est ductilis propter nimiam humiditatem continue fluentem.

Deinde cum dicit: sunt autem et haec quidem scissibilia etc., determinat de scissibili et detruncabili simul, quia ambae sunt species divisionis. Et dicit quod scissibilia sunt illa, quae prius dividuntur quam a dividente tangantur, in illa scilicet parte secundum quam dividuntur: sicut asseres ex abiete, quae quando tanguntur ut dividantur in longum, scinduntur remotius quam tangantur a dividente, ita quod divisio praecedit tactum. Quae autem non ita dividuntur, non sunt scissibilia. Et ex hoc quae sunt mollia non sunt scissibilia, quia non sic dividuntur. Neque etiam omnia dura sunt scissibilia, ut ea quae sunt comminuibilia: sed scissibilia sunt ea quae sunt sicca, non ratione qua sicca, sed inquantum habent poros dispositos secundum longitudinem, plenos corpore passibili et subtili, et adnatos, idest propinquos unum alteri. Humida autem vel mollia non scinduntur, quia carent poris, sicut aqua, pasta et cera, et huiusmodi. Comminuibilia autem non scinduntur, quia non habent poros dispositos secundum longitudinem, sed secundum omnem partem, sicut vitrum: frangibilia autem, quia non habent poros adnatos unum alteri. Multa enim dura non scinduntur, quia pori in eis non sunt pleni corpore subtili et passibili, sed duro et impassibili. Detruncabilia autem sunt, quae quando dividuntur, neque divisio praecedit tactum, sicut in scissione, neque etiam comminuuntur. Et talia sunt quae non sunt humida carentia poris, sed magis habent poros dispositos secundum latitudinem; et quia aliqua habent multos poros dispositos secundum utramque partem, ideo sunt scissibilia et detruncabilia. Et quia viscositas impedit scissionem ratione humiditatis, ideo ut sciatur quomodo fit viscosum, dicit quod viscosum, quod non frangitur sed est trahibile, sicut dictum est superius, est humidum et molle. Talia autem fiunt viscosa propter concatenationem partium adinvicem. Quae colligatio aut fit a calido movente, quod fortiter unit siccum cum humido terminato, sicut in oleo et pice, aut fit a frigido, quod fortiter et inseparabiliter comprimit humidum cum sicco. Non determinat autem de divisione simpliciter, quae est genus talium: quia divisio ut sic accidit potius ratione materiae et quantitatis, quam ratione qualitatum passivarum.

Deinde cum dicit: commassabilia autem etc., determinat de commassabilibus. Et dicit quod commassabilia sive infiltrabilia sunt ea, quae sunt capibilia, sed non habent capturam mansivam, idest non retinent figuram, quam habent quando capiuntur; quod enim talia sint capibilia, convenit eis ratione pororum interceptorum in partibus eius: quod autem redeant ad primam figuram, convenit eis ratione sicci praedominantis. Incommassabilia autem dicuntur propter causas oppositas.

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Lectio 13

ὅσα δὲ μὴ ἔχει ἢ ἰσχυροτέραν, οἷον κρύσταλλος καὶ τὰ σφόδρα χλωρά, ἄκαυστα. θυμιατὰ δ' ἐστὶ τῶν σωμάτων ὅσα ὑγρότητα ἔχει μέν, οὕτω δ' ἔχει ὥστε μὴ ἐξατμίζειν πυρουμένων χωρίς ἔστιν γὰρ ἀτμὶς ἡ ὑπὸ θερμοῦ καυστικοῦ εἰς ἀέρα καὶ πνεῦμα ἔκκρισις ἐξ ὑγροῦ διαντική. τὰ δὲ θυμιατὰ χρόνῳ εἰς ἀέρα ἐκκρίνεται, καὶ τὰ μὲν ἀφανιζόμενα ξηρά, τὰ δὲ γῆ γίγνεται. διαφέρει δ' αὕτη ἡ ἔκκρισις, ὅτι οὔτε διαίνει οὔτε πνεῦμα γίγνεται. ἔστιν δὲ πνεῦμα ῥύσις συνεχὴς ἀέρος ἐπὶ μῆκος θυμίασις δ' ἐστὶν ἡ ὑπὸ θερμοῦ καυστικοῦ κοινὴ ἔκκρισις ξηροῦ καὶ ὑγροῦ ἀθρόως διόπερ οὐ διαίνει, ἀλλὰ χρωματίζει μᾶλλον.	Some bodies are combustible and some are not. Wood, wool, bone are combustible; stone, ice are not. Bodies are combustible when their pores are such as to admit fire and their longitudinal pores contain moisture weaker than fire. If they have no moisture, or if, as in ice or very green wood, the moisture is stronger than fire, they are not combustible. Those bodies give off fumes which contain moisture, but in such a form that it does not go off separately in vapour when they are exposed to fire. For vapour is a moist secretion tending to the nature of air produced from a liquid by the agency of burning heat. Bodies that give off fumes give off secretions of the nature of air by the lapse of time: as they perish away they dry up or become earth. But the kind of secretion we are concerned with now differs from others in that it is not moist nor does it become wind (which is a continuous flow of air in a given direction). Fumes are common secretion of dry and moist together caused by the agency of burning heat. Hence they do not moisten things but rather colour them.
ἔστι δ' ἡ μὲν ξυλώδους σώματος (387b.) θυμίασις καπνός. λέγω γὰρ καὶ ὀστᾶ καὶ τρίχας καὶ πᾶν τὸ τοιοῦτον ἐν ταὐτῷ οὐ γὰρ κεῖται ὄνομα κοινόν, ἀλλὰ κατ' ἀναλογίαν ὅμως ἐν ταὐτῷ πάντ' ἐστίν, ὥσπερ καὶ Ἐμπεδοκλῆς φησιν "ταὐτὰ τρίχες καὶ φύλλα καὶ οἰωνῶν πτερὰ πυκνὰ καὶ λοπίδες γίγνονται ἐπὶ στιβαροῖσι μέλεσσιν." ἡ δὲ πίονος θυμίασις λιγνύς, ἡ δὲ λιπαροῦ κνῖσα. διὰ τοῦτο τὸ ἔλαιον οὐχ ἕψεται οὐδὲ παχύνεται, ὅτι θυμιατόν ἐστιν ἀλλ' οὐκ ἀτμιστόν ὕδωρ δ' οὐ θυμιατὸν ἀλλ' ἀτμιστόν. οἶνος δ' ὁ μὲν γλυκὺς θυμιᾶται. πίων γάρ, καὶ ταὐτὰ ποιεῖ τῷ ἐλαίῳ οὔτε γὰρ ὑπὸ ψύχους πήγνυται, καίεταί τε. ἔστιν δὲ ὀνόματι οἶνος, ἔργῳ δ' οὐκ ἔστιν οὐ γὰρ οἰνώδης ὁ χυμός διὸ οὐ μεθύσκει, ὁ τυχὼν δ' οἶνος (μικρὰν δ' ἔχει θυμίασιν διὸ ἀνίησιν φλόγα). καυστὰ δὲ δοκεῖ εἶναι ὅσα εἰς τέφραν διαλύεται τῶν σωμάτων. πάσχει δὲ τοῦτο πάντα ὅσα πέπηγεν ἢ ὑπὸ θερμοῦ ἢ ὑπ' ἀμφοῖν, ψυχροῦ καὶ θερμοῦ ταῦτα γὰρ φαίνεται κρατούμενα ὑπὸ τοῦ πυρός ἥκιστα δὲ τῶν λίθων ἡ σφραγίς, ὁ καλούμενος ἄνθραξ.	The fumes of a woody body are called smoke. (I mean to include bones and hair and everything of this kind in the same class. For there is no name common to all the objects that I mean, but, for all that, these things are all in the same class by analogy. Compare what Empedocles says: They are one and the same, hair and leaves and the thick wings of birds and scales that grow on stout limbs.) The fumes of fat are a sooty smoke and those of oily substances a greasy steam. Oil does not boil away or thicken by evaporation because it does not give off vapour but fumes. Water on the other hand does not give off fumes, but vapour. Sweet wine does give off fumes, for it contains fat and behaves like oil. It does not solidify under the influence of cold and it is apt to burn. Really it is not wine at all in spite of its name: for it does not taste like wine and consequently does not inebriate as ordinary wine does. It contains but little fumigable stuff and consequently is inflammable. All bodies are combustible that dissolve into ashes, and all bodies do this that solidify under the influence either of heat or of both heat and cold; for we find that all these bodies are mastered by fire. Of stones the precious stone called carbuncle is least amenable to fire.
τῶν δὲ καυστῶν τὰ μὲν φλογιστά ἐστιν τὰ δ' ἀφλόγιστα τούτων δ' ἔνια ἀνθρακευτά. φλογιστὰ μὲν οὖν ὅσα φλόγα δύναται παρέχεσθαι ὅσα δὲ ἀδύνατα, ἀφλόγιστα. ἔστι δὲ φλογιστὰ ὅσα μὴ ὑγρὰ ὄντα θυμιατά ἐστιν πίττα δὲ ἢ ἔλαιον ἢ κηρὸς μᾶλλον μετ' ἄλλων ἢ καθ' αὑτὰ φλογιστά μάλιστα δ' ὅσα καπνὸν ἀνίησιν. ἀνθρακευτὰ δ' ὅσα τῶν τοιούτων γῆς πλέον ἔχει ἢ καπνοῦ. ἔτι δ' ἔνια τηκτὰ ὄντα οὐ φλογιστά ἐστιν, οἷον χαλκός, καὶ φλογιστὰ οὐ τηκτά, οἷον ξύλον, τὰ δ' ἄμφω, οἷον λιβανωτός. αἴτιον δ' ὅτι τὰ μὲν ξύλα ἀθρόον ἔχει τὸ ὑγρόν, καὶ δι' ὅλου συνεχές ἐστιν, ὥστε διακάεσθαι, ὁ δὲ χαλκὸς παρ' ἕκαστον μὲν μέρος, οὐ συνεχὲς δέ, καὶ ἔλαττον ἢ ὥστε φλόγα ποιῆσαι ὁ δὲ λιβανωτὸς τῇ μὲν οὕτως τῇ δ' ἐκείνως ἔχει. φλογιστὰ δ' ἐστὶν τῶν θυμιατῶν ὅσα μὴ τηκτά ἐστιν διὰ τὸ μᾶλλον εἶναι γῆς. (τὸ ξηρὸν γὰρ ἔχει κοινὸν τῷ (388a.) πυρί τοῦτ' οὖν θερμὸν ἂν γένηται τὸ ξηρόν, πῦρ γίγνεται. διὰ τοῦτο ἡ φλὸξ πνεῦμα ἢ καπνὸς καόμενός ἐστιν.) ξύλων μὲν οὖν ἡ θυμίασις καπνός, κηροῦ δὲ καὶ λιβανωτοῦ καὶ τῶν τοιούτων καὶ πίττης, καὶ ὅσα ἔχει πίτταν ἢ τοιαῦτα, λιγνύς, ἐλαίου δὲ καὶ ὅσα ἐλαιώδη, κνῖσα, καὶ ὅσα ἥκιστα καίεται μόνα, ὅτι ὀλίγον ξηροῦ ἔχει, ἡ δὲ μετάβασις διὰ τούτου, μετὰ δ' ἑτέρου τάχιστα τοῦτο γάρ ἐστιν τὸ πῖον, ξηρὸν λιπαρόν. τὰ μὲν οὖν ἐκθυμιώμενα τῶν ὑγρῶν ὑγροῦ μᾶλλον, ὡς ἔλαιον καὶ πίττα, τὰ δὲ καόμενα ξηροῦ.	Of combustible bodies some are inflammable and some are not, and some of the former are reduced to coals. Those are called 'inflammable' which produce flame and those which do not are called 'non-inflammable'. Those fumigable bodies that are not liquid are inflammable, but pitch, oil, wax are inflammable in conjunction with other bodies rather than by themselves. Most inflammable are those bodies that give off smoke. Of bodies of this kind those that contain more earth than smoke are apt to be reduced to coals. Some bodies that can be melted are not inflammable, e.g. copper; and some bodies that cannot be melted are inflammable, e.g. wood; and some bodies can be melted and are also inflammable, e.g. frankincense. The reason is that wood has its moisture all together and this is continuous throughout and so it burns up: whereas copper has it in each part but not continuous, and insufficient in quantity to give rise to flame. In frankincense it is disposed in both of these ways. Fumigable bodies are inflammable when earth predominates in them and they are consequently such as to be unable to melt. These are inflammable because they are dry like fire. When this dry comes to be hot there is fire. This is why flame is burning smoke or dry exhalation. The fumes of wood are smoke, those of wax and frankincense and such-like, and pitch and whatever contains pitch or such-like are sooty smoke, while the fumes of oil and oily substances are a greasy steam; so are those of all substances which are not at all combustible by themselves because there is too little of the dry in them (the dry being the means by which the transition to fire is effected), but burn very readily in conjunction with something else. (For the fat is just the conjunction of the oily with the dry.) So those bodies that give off fumes, like oil and pitch, belong rather to the moist, but those that burn to the dry.

Ostendit quae sint ustibilia et quae non ustibilia. Et dicit quod quaedam corporum coagulatorum sunt ustibilia, sicut lignum et ossa, quaedam vero sunt inustibilia, sicut lapides et glacies. Ustibilia autem sunt quaecumque habent poros susceptivos ignis, et humiditatem superabilem ab igne. Talia autem sunt quae habent poros plenos humiditate aerea bene passibili. Dico quod debent habere poros: quia carentia poris non sunt ustibilia, ut glacies, quae propter defectum siccitatis caret poris. Debent etiam esse pleni humiditate aerea, quia aer est nutrimentum ignis: et propter hoc ebenus, qui inter omnia ligna est minus aereus et magis terrestris (quod ostendit pondus et nigredo eius), non est ustibilis. Debet etiam talis humiditas esse bene passibilis: quia habentia humiditatem grossam et fortem, non sunt bene ustibilia, sicut ligna multum viridia. Universaliter etiam carentia humiditate aerea non sunt ustibilia, sicut lapides, quia talis humiditas est materia ustionis.

Deinde cum dicit: exhalabilia autem etc., determinat de exhalabilibus et vaporabilibus simul. Ad cuius evidentiam sciendum est, quod aliter locutus est superius de exhalatione et vapore, et aliter in isto loco. Nam superius dixit quod exhalatio est segregatio sicca et calida, sive segregaretur a calido ustivo sive ab alio: et haec est principium venti; vapor autem est segregatio humida, et talis est principium pluviae. Hic autem dicit quod exhalabilia sunt, quae habent humiditatem non evaporabilem a calido ustivo posito sub eis, quia talia dicuntur vaporabilia: sed potius exhalabilia dicuntur, quae processu temporis paulatim segregantur in aerem, sicut apparet in pomis antiquis, in quibus separato paulatim humido aereo, ipsa remanent sicca contrahentia rugas. Vapor autem est segregatio facta virtute calidi ustivi: et ideo vapor humectat vaporabile propter humiditatem segregatam foris, et colorat ipsum ratione calidi ustivi; et est principium spiritus, idest venti, si sit vapor sive segregatio sicca praedominio. Sed exhalatio non madefacit neque colorat sensibiliter, propter paucitatem et debilitatem sui, neque etiam est principium venti. Differt autem talis segregatio in diversis; quia in lignis, et his similibus, sicut sunt pili et cornua et alia, quae sunt similiter spissa et fumabilia, vocatur fumus; quia non est impositum nomen talibus diversis segregationibus, sicut dicebat Empedocles, licet secundum rem alius sit fumus lignorum et cornuum. In pinguibus autem vocatur in Graeco lignys, in unctuosis autem dicitur knisa. Et ex hoc oleum est exhalabile, quia est unctuosum; non tamen est vaporabile, quia eius humiditas non permittit: et ideo elixari non potest, quia elixata evaporant. Aqua autem est vaporabilis a calido propter humiditatem: non tamen est exhalabilis, quia caret siccitate, quae est materia exhalationis siccae et calidae. Simile est etiam de vino dulci quod est pingue et grossum, quod patitur exhalationem sicut oleum: nam sicut oleum non coagulatur a calido neque a frigido, ingrossatur tamen ab utroque, sic et istud vinum. Et si figantur calami parvi in ipso, inflammantur. Et si sublimetur, et permisceatur cum pulvere sulphuris et sale, praestat fomentum flammae subtili: quia a sulphure augetur in eo unctuositas, a sale augetur siccitas. Et ideo est vinum solo nomine, quia vini operationem non habet, quae est inebriare: eo quod non potest evaporare. Non est autem intelligendum quod tempus sit, illud quod per se facit sive segregat exhalationem: quia tempus nullius actionis potest esse per se causa, sed solum est per se mensura aliquarum actionum. Segregatur autem talis exhalatio vel a caliditate intrinseca, vel a caliditate solis, sive continentis, non cito et in magna multitudine sicut vapor, sed paulatim et quasi insensibiliter. Et ideo dicitur fieri a tempore, quia non fit nisi in multo et longo tempore.

Deinde cum dicit: ustibilia autem etc., ostendit quae sunt inflammabilia, et quae non. Sed quia inflammabilia sunt quaedam pars ustibilium, ut melius cognoscatur quae sint inflammabilia, iterum repetit sub brevitate quae sint ustibilia. Et dicit quod talia videntur esse quaecumque possunt resolvi in cinerem: huiusmodi autem sunt quae fuerunt coagulata a solo calido, vel ab utroque, scilicet a calido et frigido, in quibus abundat siccitas propter caliditatem quae in coagulatione evaporare fecit humiditatem. Non autem sunt inflammabiles lapides, et maxime lapis carbunculus qui vocatur sigillum lapidum (licet videatur ardere propter fulgorem suae lucis), quia in ipso est fortiter commixtum humidum cum sicco, ita quod non potest resolvi in cinerem. Sed ustibilium quaedam sunt inflammabilia et quaedam non: omnia enim corpora communia terrae et aquae, quae non habent multam humiditatem aqueam sed aeream, et sunt exhalabilia, inflammantur; nam talia exhalabilia exhalant fumum, qui accensus dicitur flamma. Istorum autem quaedam faciunt per se flammam, sicut ligna, quae habent siccitatem sufficientem et exhalant fumum. Aliqua vero per se quidem non faciunt flammam, sed apposita siccis faciunt, sicut oleum, pix et huiusmodi: et ratio huius est, quia talia unctuosa, licet habeant humiditatem aeream multam quae est bene inflammabilis, deficiunt tamen in sicco. E converso autem sunt aliqua quae abundant in sicco, sed deficiunt in humido unctuoso, et ideo apposito eis unctuoso faciunt flammam meliorem. Sunt etiam quaedam quae sunt liquabilia et non inflammabilia, sicut metalla: quaedam sunt e converso inflammabilia et non liquabilia, sicut ligna: aliqua autem patiuntur utrumque, sicut thus. Causa autem quare ligna sunt inflammabilia, est quia habent humidum aereum bene diffusum et continuum in toto ligno: hoc autem humidum est materia ignis. Non sunt autem liquabilia, tum quia coagulata sunt ab utroque, tum quia liquabilium materia est humidum aqueum, non aereum quod praedominatur in lignis. Metalla autem non inflammantur, quia habent humidum aqueum multum quod repugnat igni, et aereum paucum quod est materia ignis: et propter eandem rationem sunt liquabilia. Thus autem patitur utrumque: nam ratione humidi aerei inflammatur, ratione vero humidi aquei quod in ipso est commixtum cum aereo, liquatur. Universaliter igitur quae sunt sicca, sive terrea sive etiam humida humiditate aerea, sunt bene inflammabilia; et propter hoc flamma non est aliud quam spiritus sive fumus ardens: fumus enim est segregatio aerea, et ideo est materia flammae. Eorum autem quae sunt ustibilia et non sunt inflammabilia, quaedam sunt carbonabilia: et talia sunt quaecumque habent plus terrae quam aeris, sive fumi qui est exhalatio aerea, sicut ligna viridia et ossa. Nam talia ratione sicci terrestris sunt passibilia ab igne, propter defectum vero humidi aerei non inflammantur.

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Lectio 14

10	10
τούτοις δὲ τοῖς παθήμασιν καὶ ταύταις ταῖς διαφοραῖς τὰ ὁμοιομερῆ τῶν σωμάτων, ὥσπερ εἴρηται, διαφέρει ἀλλήλων κατὰ τὴν ἁφήν, καὶ ἔτι χυμοῖς καὶ ὀσμαῖς καὶ χρώμασιν λέγω δ' ὁμοιομερῆ οἷον τά τε μεταλλευόμενα—χαλκόν, χρυσόν, ἄργυρον, καττίτερον, σίδηρον, λίθον, καὶ τἆλλα τὰ τοιαῦτα, καὶ ὅσα ἐκ τούτων γίγνεται ἐκκρινόμενα—καὶ τὰ ἐν τοῖς ζῴοις καὶ φυτοῖς, οἷον σάρκες, ὀστᾶ, νεῦρον, δέρμα, σπλάγχνον, τρίχες, ἶνες, φλέβες, ἐξ ὧν ἤδη συνέστηκε τὰ ἀνομοιομερῆ, οἷον πρόσωπον, χείρ, πούς, καὶ τἆλλα τὰ τοιαῦτα, καὶ ἐν φυτοῖς ξύλον, φλοιός, φύλλον, ῥίζα, καὶ ὅσα τοιαῦτα. ἐπεὶ δὲ ταῦτα μὲν ὑπ' ἄλλης αἰτίας συνέστηκεν, ἐξ ὧν δὲ ταῦτα ὕλη μὲν τὸ ξηρὸν καὶ ὑγρόν, ὥστε ὕδωρ καὶ γῆ (ταῦτα γὰρ προφανεστάτην ἔχει τὴν δύναμιν ἑκάτερον ἑκατέρου), τὰ δὲ ποιοῦντα τὸ θερμὸν καὶ ψυχρόν (ταῦτα γὰρ συνίστησιν καὶ πήγνυσιν ἐξ ἐκείνων), λάβωμεν τῶν ὁμοιομερῶν ποῖα γῆς εἴδη καὶ ποῖα ὕδατος καὶ ποῖα κοινά.	Homogeneous bodies differ to touch—by these affections and differences, as we have said. They also differ in respect of their smell, taste, and colour. By homogeneous bodies I mean, for instance, 'metals', gold, copper, silver, tin, iron, stone, and everything else of this kind and the bodies that are extracted from them; also the substances found in animals and plants, for instance, flesh, bones, sinew, skin, viscera, hair, fibres, veins (these are the elements of which the non-homogeneous bodies like the face, a hand, a foot, and everything of that kind are made up), and in plants, wood, bark, leaves, roots, and the rest like them. The homogeneous bodies, it is true, are constituted by a different cause, but the matter of which they are composed is the dry and the moist, that is, water and earth (for these bodies exhibit those qualities most clearly). The agents are the hot and the cold, for they constitute and make concrete the homogeneous bodies out of earth and water as matter. Let us consider, then, which of the homogeneous bodies are made of earth and which of water, and which of both.
ἔστι δὴ τῶν σωμάτων τῶν δεδημιουργημένων τὰ μὲν ὑγρά, τὰ δὲ μαλακά, τὰ δὲ σκληρά τούτων δὲ ὁπόσα σκληρὰ ἢ μαλακὰ πήξει ἐστίν, εἴρηται πρότερον. τῶν μὲν οὖν ὑγρῶν ὅσα μὲν ἐξατμίζεται, ὕδατος, ὅσα δὲ μή, ἢ γῆς ἢ κοινὰ γῆς καὶ ὕδατος, οἷον γάλα, ἢ γῆς καὶ ἀέρος, οἷον ξύλον, ἢ ὕδατος καὶ ἀέρος, οἷον ἔλαιον. καὶ ὅσα μὲν ὑπὸ θερμοῦ παχύνεται, κοινά (ἀπορήσειε δ' ἄν τις περὶ οἴνου τῶν ὑγρῶν τοῦτο (388b.) γὰρ καὶ ἐξατμισθείη ἄν, καὶ παχύνεται ὥσπερ ὁ νέος αἴτιον δ' ὅτι οὔτε ἐν ἑνὶ εἴδει λέγεται ὁ οἶνος, καὶ ὅτι ἄλλος ἄλλως ὁ γὰρ νέος μᾶλλον γῆς ἢ ὁ παλαιός διὸ καὶ παχύνεται τῷ θερμῷ μάλιστα καὶ πήγνυται ἧττον ὑπὸ τοῦ ψυχροῦ ἔχει γὰρ καὶ θερμὸν πολὺ καὶ γῆς, ὥσπερ ὁ ἐν Ἀρκαδίᾳ οὕτως ἀποξηραίνεται ὑπὲρ τοῦ καπνοῦ ἐν τοῖς ἀσκοῖς ὥστε ξυόμενος πίνεσθαι εἰ δὴ ἅπας ἰλὺν ἔχει, οὕτως ἑκατέρου ἐστίν, ἢ γῆς ἢ ὕδατος, ὡς ταύτης ἔχει πλῆθος) ὅσα δὲ ὑπὸ ψυχροῦ παχύνεται, γῆς ὅσα δ' ὑπ' ἀμφοῖν, κοινὰ πλειόνων, οἷον ἔλαιον καὶ μέλι καὶ ὁ γλυκὺς οἶνος.	Of organized bodies some are liquid, some soft, some hard. The soft and the hard are constituted by a process of solidification, as we have already explained. Those liquids that go off in vapour are made of water, those that do not are either of the nature of earth, or a mixture either of earth and water, like milk, or of earth and air, like wood, or of water and air, like oil. Those liquids which are thickened by heat are a mixture. (Wine is a liquid which raises a difficulty: for it is both liable to evaporation and it also thickens; for instance new wine does. The reason is that the word 'wine' is ambiguous and different 'wines' behave in different ways. New wine is more earthy than old, and for this reason it is more apt to be thickened by heat and less apt to be congealed by cold. For it contains much heat and a great proportion of earth, as in Arcadia, where it is so dried up in its skins by the smoke that you scrape it to drink. If all wine has some sediment in it then it will belong to earth or to water according to the quantity of the sediment it possesses.) The liquids that are thickened by cold are of the nature of earth; those that are thickened either by heat or by cold consist of more than one element, like oil and honey, and 'sweet wine'.
τῶν δὲ συνεστώτων ὅσα μὲν πέπηγεν ὑπὸ ψυχροῦ, ὕδατος, οἷον κρύσταλλος, χιών, χάλαζα, πάχνη ὅσα δ' ὑπὸ θερμοῦ, γῆς, οἷον κέραμος, τυρός, νίτρον, ἅλες ὅσα δ' ὑπ' ἀμφοῖν (τοιαῦτα δ' ἐστὶν ὅσα ψύξει ταῦτα δ' ἐστὶν ὅσα ἀμφοῖν στερήσει, καὶ θερμοῦ καὶ ὑγροῦ συνεξιόντος τῷ θερμῷ οἱ μὲν γὰρ ἅλες ὑγροῦ μόνου στερήσει πήγνυνται, καὶ ὅσα εἰλικρινῆ γῆς, ὁ δὲ κρύσταλλος θερμοῦ μόνου), ταῦτα δ' ἀμφοῖν. διὸ καὶ ὑπ' ἀμφοῖν καὶ εἶχεν ἄμφω. ὅσων μὲν οὖν ἅπαν ἐξικμάσθη, οἷον κέραμος ἢ ἤλεκτρον (καὶ γὰρ τὸ ἤλεκτρον, καὶ ὅσα λέγεται ὡς δάκρυα, ψύξει ἐστίν, οἷον σμύρνα, λιβανωτός, κόμμι καὶ τὸ ἤλεκτρον δὲ τούτου τοῦ γένους ἔοικεν, καὶ πήγνυται ἐμπεριειλημμένα γοῦν ζῷα ἐν αὐτῷ φαίνεται ὑπὸ δὲ τοῦ ποταμοῦ τὸ θερμὸν ἐξιὸν ὥσπερ τοῦ ἑψομένου μέλιτος, ὅταν εἰς ὕδωρ ἀφεθῇ, ἐξατμίζει τὸ ὑγρόν), ταῦτα πάντα γῆς. καὶ τὰ μὲν ἄτηκτα καὶ ἀμάλακτα, οἷον τὸ ἤλεκτρον καὶ λίθοι ἔνιοι, ὥσπερ οἱ πῶροι οἱ ἐν τοῖς σπηλαίοις καὶ γὰρ οὗτοι ὁμοίως γίγνονται τούτοις, καὶ οὐχ ὡς ὑπὸ πυρὸς ἀλλ' ὡς ὑπὸ τοῦ ψυχροῦ διεξιόντος τοῦ θερμοῦ συνεξέρχεται τὸ ὑγρὸν ὑπὸ τοῦ ἐξ αὐτοῦ ἐξιόντος θερμοῦ ἐν δὲ τοῖς ἑτέροις ὑπὸ τοῦ ἔξωθεν πυρός. ὅσα δὲ μὴ ὅλα, γῆς μέν ἐστι μᾶλλον, μαλακτὰ δέ, οἷον σίδηρος καὶ κέρας.	Of solid bodies those that have been solidified by cold are of water, e.g. ice, snow, hail, hoar-frost. Those solidified by heat are of earth, e.g. pottery, cheese, natron, salt. Some bodies are solidified by both heat and cold. Of this kind are those solidified by refrigeration, that is by the privation both of heat and of the moisture which departs with the heat. For salt and the bodies that are purely of earth solidify by the privation of moisture only, ice by that of heat only, these bodies by that of both. So both the active qualities and both kinds of matter were involved in the process. Of these bodies those from which all the moisture has gone are all of them of earth, like pottery or amber. (For amber, also, and the bodies called 'tears' are formed by refrigeration, like myrrh, frankincense, gum. Amber, too, appears to belong to this class of things: the animals enclosed in it show that it is formed by solidification. The heat is driven out of it by the cold of the river and causes the moisture to evaporate with it, as in the case of honey when it has been heated and is immersed in water.) Some of these bodies cannot be melted or softened; for instance, amber and certain stones, e.g. the stalactites in caves. (For these stalactites, too, are formed in the same way: the agent is not fire, but cold which drives out the heat, which, as it leaves the body, draws out the moisture with it: in the other class of bodies the agent is external fire.) In those from which the moisture has not wholly gone earth still preponderates, but they admit of softening by heat, e.g. iron and horn.
(λιβανωτοὶ δὲ καὶ τὰ τοιαῦτα παραπλησίως τοῖς ξύλοις ἀτμίζει.) ἐπεὶ οὖν τηκτά γε θετέον καὶ ὅσα τήκεται ὑπὸ πυρός, ταῦτ' ἐστὶν ὑδατωδέστερα, ἔνια (389a.) δὲ καὶ κοινά, οἷον κηρός ὅσα δὲ ὑπὸ ὕδατος, ταῦτα δὲ γῆς ὅσα δὲ μηδ' ὑφ' ἑτέρου, ταῦτα ἢ γῆς ἢ ἀμφοῖν. εἰ οὖν ἅπαντα μὲν ἢ ὑγρὰ ἢ πεπηγότα, τούτων δὲ τὰ ἐν τοῖς εἰρημένοις πάθεσιν, καὶ οὐκ ἔστιν μεταξύ, ἅπαντ' ἂν εἴη εἰρημένα οἷς διαγνωσόμεθα πότερον γῆς ἢ ὕδατος ἢ πλειόνων κοινόν, καὶ πότερον ὑπὸ πυρὸς συνέστηκεν ἢ ψυχροῦ ἢ ἀμφοῖν.	Now since we must include among 'meltables' those bodies which are melted by fire, these contain some water: indeed some of them, like wax, are common to earth and water alike. But those that are melted by water are of earth. Those that are not melted either by fire or water are of earth, or of earth and water. Since, then, all bodies are either liquid or solid, and since the things that display the affections we have enumerated belong to these two classes and there is nothing intermediate, it follows that we have given a complete account of the criteria for distinguishing whether a body consists of earth or of water or of more elements than one, and whether fire was the agent in its formation, or cold, or both.
χρυσὸς μὲν δὴ καὶ ἄργυρος καὶ χαλκὸς καὶ καττίτερος καὶ μόλυβδος καὶ ὕαλος καὶ λίθοι πολλοὶ ἀνώνυμοι ὕδατος πάντα γὰρ τήκεται ταῦτα θερμῷ. ἔτι οἶνοι ἔνιοι καὶ οὖρον καὶ ὄξος καὶ κονία καὶ ὀρὸς καὶ ἰχὼρ ὕδατος πάντα γὰρ πήγνυται ψυχρῷ. σίδηρος δὲ καὶ κέρας καὶ ὄνυξ καὶ ὀστοῦν καὶ νεῦρον καὶ ξύλον καὶ τρίχες καὶ φύλλα καὶ φλοιὸς γῆς μᾶλλον ἔτι ἤλεκτρον, σμύρνα, λίβανος, καὶ πάντα τὰ δάκρυα λεγόμενα, καὶ πῶρος, καὶ οἱ καρποί, οἷον τὰ χεδροπά, καὶ σῖτος (τὰ τοιαῦτα γὰρ τὰ μὲν σφόδρα, τὰ δὲ ἧττον μὲν τούτων, ὅμως δὲ γῆς τὰ μὲν γὰρ μαλακτά, τὰ δὲ θυμιατὰ καὶ ψύξει γεγενημένα) ἔτι νίτρον, ἅλες, λίθων γένη, ὅσα μήτε ψύξει μήτε τηκτά. αἷμα δὲ καὶ γονὴ κοινὰ γῆς καὶ ὕδατος καὶ ἀέρος, τὸ μὲν ἔχον αἷμα ἶνας μᾶλλον γῆς (διὸ ψύχει πήγνυται καὶ ὑγρῷ τήκεται), τὰ δὲ μὴ ἔχοντα ἶνας ὕδατος (διὸ καὶ οὐ πήγνυται). γονὴ δὲ πήγνυται ψύξει ἐξιόντος τοῦ ὑγροῦ μετὰ τοῦ θερμοῦ.	Gold, then, and silver and copper and tin and lead and glass and many nameless stone are of water: for they are all melted by heat. Of water, too, are some wines and urine and vinegar and lye and whey and serum: for they are all congealed by cold. In iron, horn, nails, bones, sinews, wood, hair, leaves, bark, earth preponderates. So, too, in amber, myrrh, frankincense, and all the substances called 'tears', and stalactites, and fruits, such as leguminous plants and corn. For things of this kind are, to a greater or less degree, of earth. For of all these bodies some admit of softening by heat, the rest give off fumes and are formed by refrigeration. So again in natron, salt, and those kinds of stones that are not formed by refrigeration and cannot be melted. Blood, on the other hand, and semen, are made up of earth and water and air. If the blood contains fibres, earth preponderates in it: consequently its solidifies by refrigeration and is melted by liquids; if not, it is of water and therefore does not solidify. Semen solidifies by refrigeration, its moisture leaving it together with its heat.

Postquam philosophus determinavit de qualitatibus activis et passivis secundum se, tam in generali quam in speciali de singulis speciebus eorum, nunc determinat de eis per comparationem ad corpora. Et circa hoc duo facit: primo determinat de qualitatibus passivis; secundo de qualitatibus activis, ibi: qualia autem calida et cetera. Circa primum duo facit: primo praemittit quaedam necessaria ad propositum; secundo determinat de qualitatibus passivis per comparationem ad corpora, ibi: humidorum quidem igitur et cetera. Quantum ad primum igitur, primum quod reassumit ex superioribus, est quod corpora sunt in duplici differentia. Quaedam enim sunt homoeomera sive homogenea: et talia sunt in quibus partes sunt eiusdem rationis et nominis cum toto, sicut aqua, terra, lignum, lapis, et in animalibus caro, sanguis et huiusmodi; alia autem sunt anomoeomera sive heterogenea, quae sunt diversarum rationum in toto et in partibus, sicut animal, homo, facies, manus et similia: partes enim hominis aut manus non sunt homo aut manus. Et omnia talia differunt abinvicem qualitatibus passivis, et maxime tangibilibus; differunt etiam odoribus, saporibus et coloribus et similibus: quamvis istis qualitatibus magis differant corpora homoeomera quam anomoeomera. Secundum quod reassumit, est quod causa talium corporum instrumentalis est duplex. Causa enim instrumentalis ex parte materiae est humidum et siccum: et ex consequenti causa materialis istorum est aqua et terra, quia aqua est primo humida, et terra est primo sicca. Causae vero ex parte agentis sunt calidum et frigidum: quia talia faciunt constare et coagulant talia corpora, et ex consequenti sunt activa. Et ideo considerandum est qualia sunt corpora homoeomera, scilicet species terrae et aquae et communes utrique, inquantum substant talibus qualitatibus. Tertium vero est, quod corporum constantium alia sunt humida, alia sunt dura, alia mollia. Sed de duro et molli superius satis dictum est, quomodo scilicet coagulentur: nunc autem restat dicendum de reliquis.

Deinde cum dicit: humidorum quidem igitur etc., prosequitur intentum suum, et determinat de qualitatibus corporum mixtorum per comparationem ad talia corpora. Primo ergo determinat de qualitatibus passivis, ostendendo quae corpora sunt magis humida, et quae magis sicca a praedominio. Et dicit quod omnium corporum mixtorum est triplex diversitas: nam quaedam sunt humida, ut species aquae: aliqua sunt mollia, sicut caro et nervus: aliqua autem sunt sicca vel dura, ut ossa. Et istorum ea quae coagulantur vel ingrossantur, aut coagulantur sive ingrossantur a calido, aut a frigido, aut ab utroque. Similiter etiam dicendum est de liquefactis humidorum. Igitur quaedam sunt vaporantia: et talia sunt aquea a praedominio, nam vapor est humor aqueus resolutus a calido; aut non vaporantia: et talia sunt communia terrae et aquae, ut lac, aut sunt communia terrae et aeri, sicut ligna, aut aquae et aeri, sicut oleum. Quae autem ingrossantur a calido, sunt communia terrae et aquae: nam ingrossatio facta a calido est separatio humidi superflui, et terminatio humidi derelicti cum sicco terrestri. Ingrossata vero a frigido sunt terrea a praedominio: nam in talibus est parva humiditas compressa cum multo sicco terrestri. Quae autem ingrossantur ab utroque, aut sunt communia terrae et aquae, aut terrae et aeris, sicut apparet de oleo, melle et dulci vino. Sed dubitatio oritur de vino. Nam ex ea parte qua evaporat, videtur aqueum a praedominio: ex ea vero parte qua ingrossatur a calido, videtur terreum a praedominio. Sed dicendum quod de vino tripliciter loquimur. Nam quoddam vinum est grossum terrestre, ratione cuius ingrossatur et etiam coagulatur a calido: unde si ponatur ad fumum vel solem, humido resoluto desiccatur ad modum salis; est etiam calidum, ratione cuius a frigido coagulari non potest. Et tale est vinum quod nascitur in Corinthio et apud Arcadas, et est terreum a praedominio. Quoddam vero est vinum album et debile: et istud est aquae magis. Vina vero nova ante purificationem, quae faciunt faeces, sunt communia terrae et aquae secundum magis et minus, sicut musta. Coagulata vero, aut coagulantur a frigido, et sunt aquea a praedominio, sicut nix, glacies et grando: coagulata vero a calido sunt terrea, sicut later, caseus et similia: coagulata autem ab ambobus, sunt communia terrae et aquae; quia coagulata a frigido coagulantur per solam privationem calidi, et talia sunt aquea: calido coagulantur per privationem humidi, et sunt terrea: ab ambobus autem coagulata coagulantur per privationem utriusque, et ideo sunt communia terrae et aquae. Sed coagulata ab utroque differunt inter se: quia quaedam sunt in quibus totum humidum exhalavit relicto solo humido continuante, sicut in lapidibus. Et ista sunt magis terrea et mollificari non possunt, sicut lapides et electrum: nam et electrum videtur esse huius generis coagulatorum ab utroque; sed lacrimae, et similia, sicut myrrha, thus, gumma et pori, qui sunt quasi lapides geniti ex humiditate montium distillante in speluncis, coagulantur magis per infrigidationem. Quaedam autem sunt a quibus non totum humidum exhalavit, sed aliquid remansit quod siccum fluere facit: et talia non sunt totaliter terrea, et mollificari possunt, sicut ferrum et cornu. Liquabilia vero aut liquantur ab igne, idest a calido: et talia aut sunt aquea a praedominio, sicut glacies, aut sunt communia terrae et aquae, sicut cera. Liquata autem ab aqua sunt terrea, sicut sal, liquata ab utroque sunt aut terrea aut communia, sicut sulphur. Epilogat autem quae dicta sunt de humidis et coagulatis etc., dicens quod hoc modo, scilicet sicut supra dictum est, cognoscemus quae istorum sint terrea, et quae sint aquea. Deinde quasi corollarie concludit ex dictis, quod aurum et argentum, et tam metalla quam multa alia, quae cito liquescunt ab igne, sunt aquea a praedominio, sicut urina, vinum et cetera similia: ferrum autem et cornu, et talia quae aut non liquescunt per ignem, aut non cito liquescunt, sunt terrea magis. Adhuc legumina, lacrimae, electrum, myrrha et omnia huiusmodi quae mollificantur per aquam, sunt terrea: sed inter ipsa aliqua sunt magis terrea, aliqua minus, et quae sunt magis terrea, sunt exhalabilia, quae autem minus, sunt mollificabilia. Et universaliter sunt terrea omnia, quae non coagulantur a frigido. Sanguis vero, et ea quae liquefiunt humido et coagulantur frigido, ut semen animalis, sunt communia terrae et aquae; sed aliqua ipsorum sunt magis terrea, aliqua magis aquea: quae enim habent vias, idest poros, intra se sunt magis terrea, sed tamen habent multum de aqua, et ideo coagulantur, sive ingrossantur a frigido, sicut sanguis. Quae autem non habent vias, sunt magis aquea, sicut semen: quod tamen non coagulatur a frigido, propter viscositatem continentem humidum ne exeat.

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Lectio 15

11	11
ποῖα δὲ θερμὰ ἢ ψυχρὰ τῶν πεπηγότων ἢ τῶν ὑγρῶν, ἐκ τῶν εἰρημένων δεῖ μεταδιώκειν. ὅσα μὲν οὖν ὕδατος, ὡς ἐπὶ τὸ πολὺ ψυχρά, ἐὰν μὴ ἀλλοτρίαν ἔχῃ θερμότητα, οἷον κονία, οὖρον, οἶνος ὅσα δὲ γῆς, ὡς ἐπὶ τὸ πολὺ θερμὰ διὰ τὴν τοῦ θερμοῦ δημιουργίαν, οἷον τίτανος καὶ τέφρα.	We must investigate in the light of the results we have arrived at what solid or liquid bodies are hot and what cold. Bodies consisting of water are commonly cold, unless (like lye, urine, wine) they contain foreign heat. Bodies consisting of earth, on the other hand, are commonly hot because heat was active in forming them: for instance lime and ashes.
δεῖ δὲ λαβεῖν τὴν ὕλην ψυχρότητά τινα εἶναι ἐπεὶ γὰρ τὸ ξηρὸν καὶ τὸ ὑγρὸν ὕλη (ταῦτα γὰρ παθητικά), τούτων δὲ σώματα μάλιστα γῆ καὶ ὕδωρ ἐστίν (ταῦτα γὰρ ψυχρότητι ὥρισται), δῆλον ὅτι πάντα τὰ σώματα ὅσα ἑκατέρου ἁπλῶς (389b.) τοῦ στοιχείου, ψυχρὰ μᾶλλόν ἐστιν, ἐὰν μὴ ἔχῃ ἀλλοτρίαν θερμότητα, οἷον τὸ ζέον ὕδωρ ἢ τὸ διὰ τέφρας ἠθημένον καὶ γὰρ τοῦτο ἔχει τὴν ἐκ τῆς τέφρας θερμότητα ἐν ἅπασι γάρ ἐστι θερμότης, ἢ πλείων ἢ ἐλάττων, τοῖς πεπυρωμένοις διὸ καὶ ἐν τοῖς σαπροῖς ζῷα ἐγγίγνεται ἔνεστι γὰρ θερμότης ἡ φθείρασα τὴν ἑκάστου οἰκείαν θερμότητα.	We must recognize that cold is in a sense the matter of bodies. For the dry and the moist are matter (being passive) and earth and water are the elements that primarily embody them, and they are characterized by cold. Consequently cold must predominate in every body that consists of one or other of the elements simply, unless such a body contains foreign heat as water does when it boils or when it has been strained through ashes. This latter, too, has acquired heat from the ashes, for everything that has been burnt contains more or less heat. This explains the generation of animals in putrefying bodies: the putrefying body contains the heat which destroyed its proper heat.
ὅσα δὲ κοινά, ἔχει θερμότητα συνέστηκε γὰρ τὰ πλεῖστα ὑπὸ θερμότητος πεψάσης. ἔνια δὲ σήψεις εἰσίν, οἷον τὰ συντηκτά ὥστε ἔχοντα μὲν τὴν φύσιν θερμὰ καὶ αἷμα καὶ γονὴ καὶ μυελὸς καὶ ὀπὸς καὶ πάντα τὰ τοιαῦτα, φθειρόμενα δὲ καὶ ἐξιστάμενα τῆς φύσεως οὐκέτι λείπεται γὰρ ἡ ὕλη, γῆ οὖσα ἢ ὕδωρ διὸ ἀμφότερα δοκεῖ τισιν, καὶ οἱ μὲν ψυχρὰ οἱ δὲ θερμὰ ταῦτά φασιν εἶναι, ὁρῶντες, ὅταν μὲν ἐν τῇ φύσει ὦσιν, θερμά, ὅταν δὲ χωρισθῶσιν, πηγνύμενα. ἔχει μὲν οὖν οὕτως, ὅμως δέ, ὥσπερ διώρισται, ἐν οἷς μὲν ἡ ὕλη ὕδατος τὸ πλεῖστον, ψυχρά (ἀντίκειται γὰρ μάλιστα τοῦτο τῷ πυρί), ἐν οἷς δὲ γῆς ἢ ἀέρος, θερμότερα. συμβαίνει δέ ποτε ταὐτὰ γίγνεσθαι ψυχρότατα καὶ θερμότατα ἀλλοτρίᾳ θερμότητι ὅσα γὰρ μάλιστα πέπηγε καὶ στερεώτερά ἐστιν, ταῦτα ψυχρά τε μάλιστα, ἐὰν στερηθῇ θερμότητος, καὶ κάει μάλιστα, ἐὰν πυρωθῇ, οἷον ὕδωρ καπνοῦ καὶ ὁ λίθος ὕδατος καίει μᾶλλον.	Bodies made up of earth and water are hot, for most of them derive their existence from concoction and heat, though some, like the waste products of the body, are products of putrefaction. Thus blood, semen, marrow, figjuice, and all things of the kinds are hot as long as they are in their natural state, but when they perish and fall away from that state they are so no longer. For what is left of them is their matter and that is earth and water. Hence both views are held about them, some people maintaining them to be cold and others to be warm; for they are observed to be hot when they are in their natural state, but to solidify when they have fallen away from it. That, then, is the case of mixed bodies. However, the distinction we laid down holds good: if its matter is predominantly water a body is cold (water being the complete opposite of fire), but if earth or air it tends to be warm. It sometimes happens that the coldest bodies can be raised to the highest temperature by foreign heat; for the most solid and the hardest bodies are coldest when deprived of heat and most burning after exposure to fire: thus water is more burning than smoke and stone than water.

Determinat de qualitatibus activis per comparationem similiter ad corpora, ostendens quae sint calida et quae frigida a praedominio. Et dicit quod omnia quae sunt aquea a praedominio, sunt universaliter frigida, nisi recipiant caliditatem aliunde: sicut urina, quae recipit caliditatem a digerente caliditate, lixivium, quod recipit caliditatem a cineribus calidis per quos colatur, et vinum ab aere calido circumstante. Terrea autem universaliter sunt calidiora, sicut calx et cinis. Non est autem intelligendum, quod terrea sint calida ab intrinseco et secundum naturam suam, quia ratione materiae, scilicet tam terrae quam aquae, omnia mixta sunt frigida; quia materia mixtorum sunt humidum et siccum, sicut supra dictum est: humidum autem attribuitur aquae, quae est frigida et humida, siccum vero terrae, quae est frigida et sicca; et ita semper materia mixtorum est frigida, sive sit terra, sive aqua. Sed terra dicitur calidior aqua: tum quia frigidum convenit aquae per se primo, terrae autem per participationem: tum quia utrumque ipsorum recipit alienam caliditatem, sed aqua non ita cito transmutatur ab igne sicut terra, quia terra convenit cum igne in siccitate, aqua vero in nullo, et quia aqua est rarior terra, ideo calorem non recipit in cumulo nec receptum sic fortiter tenet, ut terra; et propter hoc universaliter omnia aquea et humida sunt minus calida quam sicca et terrea. Licet autem terra et aqua, sicut dictum est, ex natura sua sint frigida, tamen in omnibus tam terreis a praedominio quam aqueis est recepta aliqua caliditas extrinseca. In cuius signum in talibus generantur animalia ex putrefactione, quorum generatio non posset esse, nisi in tali materia esset recepta aliqua caliditas particularis coagens, et simul disponens materiam ad influxum caelestem, qui est universale generans talia animalia. Quaedam autem terrea vel aquea sunt sine putrefactione, ut metalla, et ideo in his non generantur animalia. Quae autem sunt communia terrae et aquae, sunt calida: quia talia coagulantur a calido separante humidum, terminando humidum cum reliquo sicco; et ideo talia quandiu retinent mixtam naturam a generantibus data, sunt calida. Corrupta vero et perdentia naturam sunt frigida magis, praesertim cum perditur natura nobilior et acquiritur forma ignobilior, sicut in mortuis hominibus apparet; et non solum perdentia naturam, sed etiam separata a proprio loco naturali sunt frigidiora, sicut semen, sanguis et lac, quando sunt extra propria loca. Et rationem huius reddit, quia talia per corruptionem revertuntur in naturam elementi praedominantis, scilicet aquae vel terrae, quae sicut dictum est, sunt frigida. Non autem determinat de igneis vel aereis, ostendendo utrum sint calida vel frigida, tum primo, quia fere in omnibus mixtis praedominatur aqua vel terra secundum existentiam vel quantitatem: licet in aliquibus praedominetur ignis aut aer secundum virtutem; tum secundo, quia manifestum est, quod talia in quibus praedominatur ignis vel aer, sunt calida, cum haec duo elementa respectu aliorum sint activa: calidum vero est maxime activum; propter quod etiam ignea sunt magis calida quam aerea.

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Lectio 16

12	12
ἐπεὶ δὲ περὶ τούτων διώρισται, καθ' ἕκαστον λέγωμεν τί σὰρξ ἢ ὀστοῦν ἢ τῶν ἄλλων τῶν ὁμοιομερῶν ἔχομεν γὰρ ἐξ ὧν ἡ τῶν ὁμοιομερῶν φύσις συνέστηκεν, τὰ γένη αὐτῶν, τίνος ἕκαστον γένους, διὰ τῆς γενέσεως ἐκ μὲν γὰρ τῶν στοιχείων τὰ ὁμοιομερῆ, ἐκ δὲ τούτων ὡς ὕλης τὰ ὅλα ἔργα τῆς φύσεως. ἔστιν δ' ἅπαντα ὡς μὲν ἐξ ὕλης ἐκ τῶν εἰρημένων, ὡς δὲ κατ' οὐσίαν τῷ λόγῳ. ἀεὶ δὲ μᾶλλον δῆλον ἐπὶ τῶν ὑστέρων καὶ ὅλως ὅσα οἷον ὄργανα καὶ ἕνεκά του. μᾶλλον γὰρ δῆλον ὅτι ὁ νεκρὸς ἄνθρωπος ὁμωνύμως. οὕτω τοίνυν καὶ χεὶρ τελευτήσαντος ὁμωνύμως, καθάπερ καὶ (390a.) αὐλοὶ λίθινοι λεχθείησαν οἷον γὰρ καὶ ταῦτα ὄργανα ἄττα ἔοικεν εἶναι. ἧττον δ' ἐπὶ σαρκὸς καὶ ὀστοῦ τὰ τοιαῦτα δῆλα. ἔτι δ' ἐπὶ πυρὸς καὶ ὕδατος ἧττον τὸ γὰρ οὗ ἕνεκα ἥκιστα ἐνταῦθα δῆλον, ὅπου δὴ πλεῖστον τῆς ὕλης ὥσπερ γὰρ εἰ καὶ τὰ ἔσχατα ληφθείη, ἡ μὲν ὕλη οὐδὲν ἄλλο παρ' αὐτήν, ἡ δ' οὐσία οὐδὲν ἄλλο ἢ λόγος, τὰ δὲ μεταξὺ ἀνάλογον τῷ ἐγγὺς εἶναι ἕκαστον, ἐπεὶ καὶ τούτων ὁτιοῦν ἐστιν ἕνεκά του, καὶ οὐ πάντως ἔχον ὕδωρ ἢ πῦρ, ὥσπερ οὐδὲ σὰρξ οὐδὲ σπλάγχνον. τούτων δ' ἔτι μᾶλλον πρόσωπον καὶ χείρ. ἅπαντα δ' ἐστὶν ὡρισμένα τῷ ἔργῳ τὰ μὲν γὰρ δυνάμενα ποιεῖν τὸ αὑτῶν ἔργον ἀληθῶς ἐστιν ἕκαστον, οἷον ὀφθαλμὸς εἰ ὁρᾷ, τὸ δὲ μὴ δυνάμενον ὁμωνύμως, οἷον ὁ τεθνεὼς ἢ ὁ λίθινος οὐδὲ γὰρ πρίων ὁ ξύλινος, ἀλλ' ἢ ὡς εἰκών. οὕτω τοίνυν καὶ σάρξ ἀλλὰ τὸ ἔργον αὐτῆς ἧττον δῆλον ἢ τὸ τῆς γλώττης. ὁμοίως δὲ καὶ πῦρ ἀλλ' ἔτι ἧττον ἴσως δῆλον φυσικῶς ἢ τὸ τῆς σαρκὸς ἔργον. ὁμοίως δὲ καὶ τὰ ἐν τοῖς φυτοῖς καὶ τὰ ἄψυχα, οἷον χαλκὸς καὶ ἄργυρος πάντα γὰρ δυνάμει τινί ἐστιν ἢ τοῦ ποιεῖν ἢ τοῦ πάσχειν, ὥσπερ σὰρξ καὶ νεῦρον ἀλλ' οἱ λόγοι αὐτῶν οὐκ ἀκριβεῖς. ὥστε πότε ὑπάρχει καὶ πότε οὔ, οὐ ῥᾴδιον διιδεῖν, ἂν μὴ σφόδρα ἐξίτηλον ᾖ καὶ τὰ σχήματα μόνα ᾖ λοιπά, οἷον καὶ τὰ τῶν παλαιουμένων νεκρῶν σώματα ἐξαίφνης τέφρα γίγνεται ἐν ταῖς θήκαις καὶ καρποὶ μόνον τῷ (390b.) σχήματι, τὴν δ' αἴσθησιν οὐ φαίνονται, παλαιούμενοι σφόδρα καὶ τὰ ἐκ τοῦ γάλακτος πηγνύμενα.	Having explained all this we must describe the nature of flesh, bone, and the other homogeneous bodies severally. Our account of the formation of the homogeneous bodies has given us the elements out of which they are compounded and the classes into which they fall, and has made it clear to which class each of those bodies belongs. The homogeneous bodies are made up of the elements, and all the works of nature in turn of the homogeneous bodies as matter. All the homogeneous bodies consist of the elements described, as matter, but their essential nature is determined by their definition. This fact is always clearer in the case of the later products of those, in fact, that are instruments, as it were, and have an end: it is clearer, for instance, that a dead man is a man only in name. And so the hand of a dead man, too, will in the same way be a hand in name only, just as stone flutes might still be called flutes: for these members, too, are instruments of a kind. But in the case of flesh and bone the fact is not so clear to see, and in that of fire and water even less. For the end is least obvious there where matter predominates most. If you take the extremes, matter is pure matter and the essence is pure definition; but the bodies intermediate between the two are matter or definition in proportion as they are near to either. For each of those elements has an end and is not water or fire in any and every condition of itself, just as flesh is not flesh nor viscera viscera, and the same is true in a higher degree with face and hand. What a thing is always determined by its function: a thing really is itself when it can perform its function; an eye, for instance, when it can see. When a thing cannot do so it is that thing only in name, like a dead eye or one made of stone, just as a wooden saw is no more a saw than one in a picture. The same, then, is true of flesh, except that its function is less clear than that of the tongue. So, too, with fire; but its function is perhaps even harder to specify by physical inquiry than that of flesh. The parts of plants, and inanimate bodies like copper and silver, are in the same case. They all are what they are in virtue of a certain power of action or passion—just like flesh and sinew. But we cannot state their form accurately, and so it is not easy to tell when they are really there and when they are not unless the body is thoroughly corrupted and its shape only remains. So ancient corpses suddenly become ashes in the grave and very old fruit preserves its shape only but not its taste: so, too, with the solids that form from milk.
τὰ μὲν οὖν τοιαῦτα μόρια θερμότητι καὶ ψυχρότητι καὶ ταῖς ὑπὸ τούτων κινήσεσιν ἐνδέχεται γίγνεσθαι, πηγνύμενα τῷ θερμῷ καὶ τῷ ψυχρῷ λέγω δ' ὅσα ὁμοιομερῆ, οἷον σάρκα, ὀστοῦν, τρίχας, νεῦρον, καὶ ὅσα τοιαῦτα πάντα γὰρ διαφέρει ταῖς πρότερον εἰρημέναις διαφοραῖς, τάσει, ἕλξει, θραύσει, σκληρότητι, μαλακότητι καὶ τοῖς ἄλλοις τοῖς τοιούτοις ταῦτα δὲ ὑπὸ θερμοῦ καὶ ψυχροῦ καὶ τῶν κινήσεων γίγνεται μειγνυμένων. τὰ δ' ἐκ τούτων συνεστῶτα οὐδενὶ ἂν ἔτι δόξειεν τὰ ἀνομοιομερῆ, οἷον κεφαλὴ ἢ χεὶρ ἢ πούς, ἀλλ' ὥσπερ καὶ τοῦ χαλκὸν μὲν ἢ ἄργυρον γενέσθαι αἰτία ψυχρότης καὶ θερμότης καὶ κίνησις, τοῦ δὲ πρίονα ἢ φιάλην ἢ κιβωτὸν οὐκέτι, ἀλλ' ἐνταῦθα μὲν τέχνη, ἐκεῖ δὲ φύσις ἢ ἄλλη τις αἰτία. εἰ οὖν ἔχομεν τίνος γένους ἕκαστον τῶν ὁμοιομερῶν, ληπτέον καθ' ἕκαστον τί ἐστιν, οἷον τί αἷμα ἢ σὰρξ ἢ σπέρμα καὶ τῶν ἄλλων ἕκαστον οὕτω γὰρ ἴσμεν ἕκαστον διὰ τί καὶ τί ἐστιν, ἐὰν ἢ τὴν ὕλην ἢ τὸν λόγον ἔχωμεν, μάλιστα δ' ὅταν ἄμφω τῆς τε γενέσεως καὶ φθορᾶς, καὶ πόθεν ἡ ἀρχὴ τῆς κινήσεως. δηλωθέντων δὲ τούτων ὁμοίως τὰ ἀνομοιομερῆ θεωρητέον, καὶ τέλος τὰ ἐκ τούτων συνεστῶτα, οἷον ἄνθρωπον, φυτόν, καὶ τἆλλα τὰ τοιαῦτα.	Now heat and cold and the motions they set up as the bodies are solidified by the hot and the cold are sufficient to form all such parts as are the homogeneous bodies, flesh, bone, hair, sinew, and the rest. For they are all of them differentiated by the various qualities enumerated above, tension, tractility, comminuibility, hardness, softness, and the rest of them: all of which are derived from the hot and the cold and the mixture of their motions. But no one would go as far as to consider them sufficient in the case of the non-homogeneous parts (like the head, the hand, or the foot) which these homogeneous parts go to make up. Cold and heat and their motion would be admitted to account for the formation of copper or silver, but not for that of a saw, a bowl, or a box. So here, save that in the examples given the cause is art, but in the nonhomogeneous bodies nature or some other cause. Since, then, we know to what element each of the homogeneous bodies belongs, we must now find the definition of each of them, the answer, that is, to the question, 'what is' flesh, semen, and the rest? For we know the cause of a thing and its definition when we know the material or the formal or, better, both the material and the formal conditions of its generation and destruction, and the efficient cause of it. After the homogeneous bodies have been explained we must consider the non-homogeneous too, and lastly the bodies made up of these, such as man, plants, and the rest.

Determinat de homoeomeris, idest homogeneis corporibus, ostendendo quomodo differant per passiones determinatas, et magis continuando ea quae determinata sunt ad libros sequentes. Primo igitur praemittit duo. Quorum primum est, quod determinando de homoeomeris de facili cognoscemus reliqua, quia omnia constant ex homoeomeris tanquam ex partibus. Ipsa autem homoeomera possunt cognosci ex dictis: quia determinatum est a quibus generentur tanquam ab agente, quia scilicet a calido et frigido, et ex quibus fiant tanquam ex materia, quia ex humido et sicco, et ex consequenti ex aqua et terra, quae sunt materia omnium mixtorum. Secundum est, quod formae homoeomerorum substantiales sunt nobis ignotae: et ex consequenti talia corpora non sunt nobis cognita, nisi per accidentia praedeterminata, quia cognitionis quidditativae principium est forma substantialis. Quod autem tales formae sint nobis ignotae manifestat, quia formae quanto sunt posteriores in via generationis, tanto magis sunt notae: sicut anima quae est ultima in via generationis et est principium diversarum operationum, est nota valde, et ideo discernimus inter animalia viva et mortua; sed forma carnis non est sic nobis nota, et ideo non ita bene discernimus inter carnem vivam et mortuam: adhuc etiam formae ignis et aeris sunt nobis minus notae. Quod autem ita sit, dupliciter probat. Primo, quia materia quae de se est pura potentia, non est cognoscibilis nisi per analogiam ad formam, forma vero quae est actus et perfectio, est cognoscibilis per se: formae igitur intermediae quanto sunt remotiores a materia et propinquiores ultimae formae, tanto magis sunt notae; sed formae homoeomerorum sunt propinquae materiae et elementis; igitur sunt minus notae. Secundo, omne corpus quod generatur ex materia, habet aliquam formam per quam determinatur ad speciem, et talis forma cognoscitur per propriam operationem: quia unumquodque tunc vere dicimus esse tale, quando potest facere proprium opus illius, sicut vere dicimus esse oculum cum videt, eum autem qui non videt, sicut oculus lapideus aut mortuus, non vocamus oculum nisi aequivoce et metaphorice, ut serra lapidea vel lignea quae non potest secare, est serra aequivoce; operationes autem animae sunt nobis magis notae quam operationes carnis vel ignis, et operationes plantarum sunt magis cognitae quam operationes inanimatorum, ut metallorum et aliorum homoeomerorum: quia omnia habent aliquam formam et virtutem, sed non cognoscimus recte rationem et formam ipsorum, quia operatio earum est nobis incognita. Ex hoc sequitur, quod omnis nostra cognitio quam habemus de formis substantialibus, est per operationem sive per alia accidentia et figuras, et ideo discernimus inter hominem mortuum et vivum; non autem discernimus ita bene inter carnem vivam et mortuam, quia operatio eius non est cognita, et figura videtur esse eadem: cuius autem operatio est incognita, illud non cognoscitur nisi per figuram, sicut antiquorum mortuorum corpora quae sunt redacta in cinerem, non cognoscimus nisi per aliquam figuram. Concludit igitur quod homoeomera, idest corpora quae habent partes eiusdem rationis cum toto, sicut caro, nervus, pili, fiunt tanquam ab agente, scilicet instrumentali, a caliditate et frigiditate per motum factum ab ipsis, tanquam ex materia fiunt ex humido et sicco, et differunt inter se per praedeterminatas passiones, scilicet duritie, mollitie, tractione, comminutione etc.: et ex hac oportet ea cognoscere quale sit unumquodque, ex talibus praedeterminatis, postquam forma substantialis est nobis incognita. Sed corpora dissimilium partium, ut facies, manus, non differunt per tales qualitates nisi ratione eorum ex quibus componuntur, sicut phialae vel arcae non est causa calidum vel frigidum, nisi inquantum sunt causa argenti vel ligni ex quibus talia componuntur: sed differunt formis naturalibus existentibus in eis, sicut artificialia differunt formis artis, licet materia eorum, ut metalla, differant passionibus istis. Deinde epilogat, dicens quod isto modo cognoscimus quid sint homoeomera, quia tunc cognoscimus aliquid, cum cognoscimus causam materialem eius vel formalem, et melius cum cognoscimus utramque. Maxime autem cognoscimus aliquid, cum cognoscimus omnes eius causas, quia perfecta cognitio habetur de rebus per omnes causas earum. Cum autem cognoscimus homogenea, quae sunt partes aliorum, considerandum erit de aliis, ut de animalibus et plantis, quae constituuntur ex his partibus.

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