14

is completely destroyed, being parched by the heat, so that not even a small remnant is left behind, as the flame has dried up the moisture. And this can no longer be explained by the argument concerning vapors. For the region above the clouds, which lies over this murky and windy air, does not admit anything heavier into the subtlety of its own nature; but all vapors and all exhalations have as the limit of their upward motion the density of the terrestrial air in that region, which they are not by nature able to pass through to what is above. For none of the denser things would be left behind in what is subtle and ethereal. Thus, indeed, those who have recorded these things say that the peaks of some exceedingly high mountains are always above the clouds and inaccessible to winds, and that it is impossible for birds to fly over them, no less than for sea creatures to live in the air, so that it is clearly demonstrated through all these things that there is some boundary in the air toward the region lying above, which sets a limit for all the denser exhalations from the earth; for which reason also, until the season of summer, the snow on the peaks remains unmelted, as the condensation of vapors in that region continuously cools the air. But also the fiery trails, which some call shooting stars, those wise in these matters explain as occurring from the same cause, when by the force of certain winds some of the thicker and more material air is pushed up into the ethereal place, it immediately bursts into flame upon reaching the upper region; and according to the impulse given by the wind, the flame is carried along as it streams; but when the wind is extinguished, the flame also dies out with it. Therefore, concerning the wind, it is not possible to say again that vapors are formed in the disappearance of the cloud; so that through them one might hope, in a manner similar to what was said below, for the return of the moisture that was taken up, one is forced to agree with those who hold that the moisture is burned up, and passes away into non-existence. But I am persuaded that the moisture in the vapors is destroyed by the exceeding flame, judging it to be vain and contentious to fight against what is evident; but since it is fitting not to grow weary in tracking down the truth from every side, I say that although these things happen, the measure of the moist nature is nevertheless preserved undiminished, and what is expended is always in every way replaced for what is lacking. And what makes this supposition of mine firm, is this: In the working of fire among us, we learn this through experience, that fire does not consume all the qualities of the matter, but only that which it seizes upon; for instance, in the case of the substance of oil, since it has been separated from the cold quality, in this substance the moisture was easily drawn out by the heat of the fire, and became a flame. But not only was the oil changed into flame by the fire, but also the moisture of the fire that came from the oil, he says, after the fire, becomes dry dust; which the soot from the lamp clearly shows, blackening what is above the flame; which, if it should happen to a greater extent, some mass also turns back to the place blackened by the soot. From which it is clear that the oil, having been dried out by the fire, is changed into fine and invisible particles, and thus comes to be in the air, and from there settles upon the earth. And that there is a fine diffusion of soot in the air is shown by the fact that the nostrils of those breathing this air are blackened. And often also what is spit up from within the chest is seen to be black, because it too is colored by the color of the soot that enters along with the breathing of the air. It is clear then from these things that the moisture of the oil was transformed into dryness, but the bulk of the substance did not vanish into non-existence, being scattered into the air in fine and invisible particles. What, therefore, we have learned in the case of this liquid through the action of what happens, that the liquid is only changed into dryness, the material substance does not completely disappear; this one also concerning

14

τὸ παντελὲς ἀφανίζεται καταφρυγέντα τῷ καύ σωνι, ὡς μηδὲ βραχύ τι λείψανον ὑπολειφθῆναι, τοῦ φλογμοῦ τὴν ἰκμάδα καταξηράναντος. Τοῦτο δὲ οὐκ έτι ἐστὶ τῷ τῶν ἀτμῶν λόγῳ παραμυθήσασθαι. Ἡ γὰρ ἄνω τῶν νεφῶν κατάστασις ἡ τοῦ θολεροῦ τούτου καὶ πνευματώδους ἀέρος ὑπερκειμένη, οὐδὲν τῶν βαρυτέ ρων ἐν τῇ λεπτότητι τῆς ἰδίας φύσεως καταδέχεται· ἀλλὰ πάντες ἀτμοὶ καὶ πᾶσαι ἀναθυμιάσεις ὅρον ἔχουσι τῆς ἐπὶ τὸ ἄνω φορᾶς τὴν τοῦ περιγείου ἀέρος κατὰ τὸ μέρος ἐκεῖνο παχύτητα, ἧς διαδῦναι ἐπὶ τὸ ἄνω φύσιν οὐκ ἔχει. Οὐ γὰρ ἂν ὑπολειφθείη ἐν τῷ λεπτῷ τε καὶ αἰθεροειδεῖ τῶν παχυμερεστέρων οὐδέν. Οὕτως οὖν καὶ ὀρῶν τινων ὑπερμεγεθῶν τὰς ἀκρωρείας οἱ ἱστορήσαν τες λέγουσιν ὑπερνεφεῖς μὲν εἶναι ἀεὶ καὶ ἀνεφίκτους τοῖς πνεύμασι, καὶ τοῖς πτηνοῖς ἀμήχανον τὴν ἐπ' ἐκεί νων γενέσθαι πτῆσιν, οὐχ ἧττον ἢ τοῖς ὑποβρυχίοις τὴν ἐν ἀέρι ζωὴν, ὡς διὰ πάντων σαφῶς ἀποδείκνυσθαι, εἶναί τι κατὰ τὸν ἀέρα πρὸς τὸν ὑπερκείμενον χῶ ρον μεθόριον, ὃ πᾶσι τοῖς παχυμερεστέροις τῶν ἐκ τῆς γῆς ἀναθυμιωμένων ὁρίζει τὴν στάσιν· οὗ χάριν καὶ μέχρι τῆς ὥρας τοῦ θέρους, ἄτηκτος ἡ ἐπὶ τῶν ἀκρωρειῶν διαμένει χιὼν, τῆς τῶν ἀτμῶν συστάσεως κατ' ἐκεῖνο τὸ μέρος διηνεκῶς τὸν ἀέρα καταψυχού σης. Ἀλλὰ καὶ τοὺς πυροειδεῖς ὁλκοὺς, οὕς τινες διάττοντας καλοῦσιν ἀστέρας, ἐκ τῆς αὐτῆς αἰτίας γίνεσθαι, φυσιολογοῦσιν οἱ ταῦτα σοφοὶ, ὅταν ἔκ τινων πνευμάτων βίας ὑπερχεθῇ τι τοῦ παχυτέρου καὶ ὑλωδεστέρου ἀέρος ἐπὶ τὸν αἰθέριον τόπον, εὐθὺς ἐκφλογοῦσθαι ἄνω γενόμενον· καὶ κατὰ τὴν ἐνδο θεῖσαν ἐκ τοῦ πνεύματος ὁρμὴν, τὴν φλόγα ῥέουσαν 97 φέρεσθαι· σβεσθέντος δὲ τοῦ πνεύματος, συναπομα ραίνεσθαι καὶ τὴν φλόγα. Τῷ πνεύματι τοίνυν οὐκ ἔστι δυνατὸν εἰπεῖν πάλιν ἀτμοὺς ἐν τῷ ἀφανισμῷ τοῦ νέφους συνίστασθαι· ὡς δι' ἐκείνων ἐλπίσαι, καθ' ὁμοιότητα τῶν κάτωθεν ῥηθέντων, τοῦ ἀναλη φθέντος ὑγροῦ τὴν ἐπάνοδον, ἀνάγκη συντίθεσθαι τοῖς ἐκκαίεσθαι τὸ ὑγρὸν δογματίζουσι, καὶ εἰς τὸ μὴ ὂν περιΐστασθαι. Ἀλλ' ἐγὼ τὸ μὲν ἀφανίζεσθαι τῷ ὑπερβάλλοντι φλογμῷ τὴν ἐν τοῖς ἀτμοῖς ὑγρό τητα πείθομαι, μάταιον καὶ ἐριστικὸν εἶναι κρίνων, τὸ τοῖς φανεροῖς ἀντιμάχεσθαι· ἐπεὶ δὲ προσήκει μὴ καμεῖν πανταχόθεν ἀνιχνεύοντας τὴν ἀλήθειαν, οὐδὲν ἧττον τούτων γινομένων, φημὶ τὸ μέτρον τῆς ὑγρᾶς φύσεως ἀμείωτον διασώζεσθαι, καὶ ἀεὶ τὸ δαπανώ μενον ἀντεισάγεσθαι πάντως τῷ λείποντι. Ὃ δέ μοι τὴν τοιαύτην ὑπόληψιν βεβαίαν ποιεῖ, τοῦτ' ἔστιν· Ἐν τῇ καθ' ἡμᾶς τοῦ πυρὸς ἐνεργείᾳ, τοῦτο διὰ τῆς πείρας μανθάνομεν, ὅτι οὐ πάσας τὰς ποιότητας τῆς ὕλης τὸ πῦρ ἐπιβόσκεται, ἀλλ' ἧς ἂν περιδράξηται· οἷον φέρε εἰπεῖν ἐπὶ τῆς τοῦ ἐλαίου ὕλης, ἐπειδὴ κε χώρισται τῆς ψυχρᾶς ποιότητος, ἐν τῇ ὕλῃ ταύτῃ τὸ ὑγρὸν εὐκόλως ὑπὸ τῆς θερμότητος τοῦ πυρὸς ἐξ ειλκύσθη, καὶ φλὸξ ἐγένετο. Ἀλλ' οὐ μόνον εἰς φλόγα τὸ ἔλαιον διὰ τοῦ πυρὸς ἠλλοιώθη, ἀλλὰ καὶ τὸ τοῦ πυρὸς τοῦ γενομένου ἀπὸ τοῦ ἐλαίου, φησὶν, ὑγρὸν μετὰ τὸ πῦρ, ξηρὰ γίνεται κόνις· ὅπερ σαφῶς δεί κνυσιν ἡ ἐκ τοῦ λύχνου λιγνὺς καταμελαίνουσα τὸ τῆς φλογὸς ὑπερκείμενον· ὅπερ εἰ ἐπὶ πλεῖον γί γνοιτο, καὶ ὄγκος τις ὑποστρέφεσθαι τῷ διὰ τῆς λι γνύος μελαινομένῳ τόπῳ. Ὅθεν δῆλόν ἐστιν, ὅτι εἰς λεπτά τε καὶ ἀφανῆ μόρια τὸ ἔλαιον διὰ τοῦ πυρὸς ἀποξηρανθὲν ἀλλοιοῦται, καὶ οὕτως ἐν τῷ ἀέρι γίνεται, κἀκεῖθεν ἐπὶ τὴν γῆν συνιζάνει. ∆είκνυσι δὲ τὸ ἐν τῷ ἀέρι τὴν λεπτομερῆ τῆς λιγνύος εἶναι διάχυσιν, ἐκ τοῦ τοὺς μυκτῆρας τῶν τὸν ἀέρα τοῦτον ἀναπνεόντων ὑπομελαίνεσθαι. Πολλάκις δὲ καὶ τὸ ἔνδοθεν ἐκ τοῦ θώρακος ἀναπτυόμενον, μέλαν ὁρᾶσθαι, διὰ τὸ τῷ χρώματι τῆς λιγνύος καὶ αὐτὸ καταχρώννυσθαι τῷ διὰ τῆς τοῦ ἀέρος ἀναπνοῆς συνεισπίπτοντι. Οὐκοῦν δῆλόν ἐστιν ἐκ τούτων, ὅτι τοῦ ἐλαίου τὸ μὲν ὑγρὸν εἰς ξηρότητα μετεποιήθη, ὁ δὲ κατὰ τὴν ὕλην ὄγκος οὐκ εἰς ἀνυπαρξίαν ἠφανίσθη διὰ τῶν λεπτῶν τε καὶ ἀφανῶν μορίων ἐνσκεδασθεὶς τῷ ἀέρι. Ὅπερ τοίνυν ἐπὶ τοῦ ὑγροῦ τούτου διὰ τῆς τῶν γινομένων ἐνεργείας ἐμάθομεν, ὅτι ἀλλοιοῦται μόνον τὸ ὑγρὸν εἰς ξηρότητα, οὐκ εἰς τὸ παντελὲς τὸ ὑλικὸν ἀφανίζεται· τοῦτό τις καὶ περὶ