§25.13. . . ἢ ὅτι ὁ ἀὴρ ἄνω φέρεται;
... or is it because the air is carried upward?
ὁ γὰρ ἀσκὸς ὅταν μὲν κενὸς ᾖ κάτω φέρεται, ὅταν δὲ φυσηθῇ, ἄνω ἐπιμένει διὰ τὸ τοῦτον ἀναφέρειν.
For when the skin is empty, it is carried downward, but when it is blown up, it remains upward because this air carries it up.
εἰ δὲ ὁ ἀὴρ ἀνακουφίζει καὶ κωλύει κάτω φέρεσθαι, διὰ τί βαρύτεροι γίνονται φυσηθέντες;
But if the air lightens it and prevents it from being carried downward, why do they become heavier when blown up?
καὶ πῶς, ὅτε μὲν βαρύτερός ἐστιν, ἐπιμένει, κουφότερος δὲ γενόμενος καταφέρεται;
And how is it that, when it is heavier, it remains, but having become lighter, it is carried down?
§25.14Διὰ τί ὁ ἀὴρ. . . οὐκ ἄνω φέρεται;
Why does the air... not travel upward?
εἰ γὰρ τὰ πνεύματα τούτου κινουμένου ὑπὸ τοῦ θερμοῦ γίνεται, πέφυκεν δὲ τὸ πῦρ ἄνω φέρεσθαι, καὶ τὸ πνεῦμα εἰς τὸ ἄνω ἐβάδιζεν, εἴπερ τό τε κινοῦν εἰς τὸ ἄνω θεῖ καὶ τὸ κινούμενον οὕτω πέφυκε φέρεσθαι.
For if the winds occur when this is moved by the heat, and fire by nature travels upward, and the wind also went toward the upper region, if indeed the mover runs toward the upper region and the moved is by nature carried in this way.
νῦν δὲ φαίνεται λοξὴν τὴν φορὰν ποιούμενος.
But now it appears to make its motion slantwise.
§25.15Διὰ τί τὸ ἀφ’ ἕω ψυχρότερον ἢ τὸ ἀφ’ ἑσπέρας;
Why is the air of the morning colder than that of the evening?
ἢ ὅτι τὸ μὲν ἐγγύτερον μέσων νυκτῶν, τὸ δὲ μεσημβρίας;
Or is it because the former is closer to midnight, and the latter to midday?
ἔστι δὲ ἡ μεσημβρία θερμότατον διὰ τὸ εἶναι ἐγγύτατον ἡλίου, αἱ δὲ μέσαι νύκτες ψυχρότεραι διὰ τὸ ἐναντίον.
And midday is warmest because of being closest to the sun, while midnight is colder because of the opposite.
§25.16Διὰ τί αἱ νύκτες τῶν ἡμερῶν ἐν ταῖς ἀλέαις πνιγηρότεραι;
Why are nights more stifling than days in hot weather?
ἢ διὰ τὴν ἄπνοιαν;
Or is it because of the lack of wind?
οἱ γὰρ ἐτησίαι καὶ πρόδρομοι τὰς νύκτας ἧττον πνέουσιν.
For the Etesian winds and their precursors blow less during the nights.
§25.17Διὰ τί τὰ ἐν τοῖς ἀσκοῖς ἄσηπτα φυσηθεῖσιν, καὶ ἐν τοῖς περιπωματιζομένοις;
Why do things in skins remain uncorrupted when they are blown up, and also in those vessels that are tightly covered?
ἢ διότι σήπεται μὲν κινούμενα, ἅπαντα δὲ τὰ πλήρη ἀκίνητα, ταῦτα δὲ πλήρη.
Is it because they corrupt when moved, but all things that are full are motionless, and these are full?
§25.18Διὰ τί τῆς αἰθρίας μᾶλλον ψῦχος γίνεται ἢ ἐπινεφέλων ὄντων;
Why is there more cold in clear weather than when it is cloudy?
τὰ δὲ ἄστρα καὶ ὁ οὐρανὸς θερμός.
Yet the stars and the heaven are hot.
ἢ ὅτι οὐθὲν ἀποστέγει ἐν τῇ αἰθρίᾳ τὴν ἀτμίδα, ἀλλὰ διαχεῖται ἐν δὲ τοῖς ἐπινεφέλοις ἀποστέγεται;
Or is it because nothing shelters the vapor in clear weather, but it is dispersed, whereas in cloudy weather it is sheltered?
καὶ βορείων γε ἢ νοτίων διὰ τὸ αὐτό· ὁ μὲν γὰρ νότος ἄγει τὸ τοιοῦτον, ὁ δὲ ἀπωθεῖ.
And this is the same with northerly and southerly winds; for the south wind brings such a thing, but the north wind drives it away.
καὶ ἀτμίζειν δὲ φαίνεται βορείοις μᾶλλον ἢ νοτίοις, καὶ χειμῶνος ἢ θέρους.
And vapor seems to rise more during northerly winds than southerly ones, and in winter than in summer.
ἢ παρὰ τὸ ἀνόμοιον;
Or is it because of the dissimilarity?
ἢ ὅτι θερμοῦ ψυχομένου ἐστὶν ἡ ἀτμίς;
Or because vapor is of a hot thing being cooled?
§25.19Διὰ τί ἀὴρ ὁ ἐλάττων θερμότερος τοῦ πλείονος;
Why is a smaller amount of air hotter than a larger amount?
αἱ γὰρ στενοχωρίαι ἀλεεινότεραι.
For narrow places are warmer.
ἢ διότι κινεῖται μᾶλλον ὁ πολύς, ἡ δὲ κίνησις ποιεῖ ψυχρόν;
Or is it because a large amount of air moves more, and movement produces cold?
σημεῖον δὲ τούτου, ὅτι κινούμενα ψύχεται τὰ θερμά.
And a sign of this is that hot things are cooled when moved.
§25.20Διὰ τί ὕδωρ μὲν καὶ γῆ σήπεται, ἀὴρ δὲ καὶ πῦρ οὐ σήπεται;
Why do water and earth corrupt, but air and fire do not?
ἢ ὅτι θερμότατον γίνεται τὸ σηπόμενον ἅπαν, πυρὸς δὲ οὐδὲν θερμότερον;
Is it because everything that corrupts becomes extremely hot, and nothing is hotter than fire?
ἢ ὅτι ψυχθῆναι δεῖ πρότερον, τὸ δὲ πῦρ ἀεὶ θερμόν, ὁ δὲ ἀὴρ πυρὸς πλήρης.
Or is it because it must first be cooled, but fire is always hot, and air is full of fire?
σήπεται δὲ οὐδὲν θερμόν, ἀλλὰ ψυχθέν· γῆ δὲ καὶ ὕδωρ καὶ ἀὴρ καὶ θερμὰ καὶ ψυχρὰ γίνεται.
And nothing that is hot corrupts, but rather what is cooled; while earth, water, and air become both hot and cold.
§25.21Διὰ τί τὰ ἐπινέφελα ἀλεεινότερα τῶν αἰθρίων;
Why are cloudy days warmer than clear ones?
πότερον ὡς οἱ ἀρχαῖοι ἔλεγον ὅτι τὰ ἄστρα ψυχρά;
Is it, as the ancients used to say, because the stars are cold?
ἢ λίαν τοῦτό γε ἄτοπον, ἀλλὰ διότι ἀτμίζει;
Or is this indeed too absurd, but rather because vapor rises?
ἐπισημαντέον δὲ ὅτι ἐν νηνεμίᾳ ἡ δρόσος καὶ ἡ πάχνη γίνεται.
And it should be noted that dew and hoarfrost occur in calm weather.
ὅταν μὲν οὖν αἰθρία ᾖ, διαπνεῖ τὸ θερμόν, ὑφ’ οὑ ἀνάγεται τὸ ὑγρόν, ὥστε ψυχρὸς ὁ ἀήρ· διὸ καὶ δροσίζει ἀφιέμενον τὸ ὑγρὸν ἀπὸ τοῦ θερμοῦ.
When, therefore, it is clear, the heat breathes through, by which the moisture is carried up, so that the air is cold; therefore, the moisture, when released from the heat, falls as dew.
ὅταν δὲ ἐπινέφελον ᾖ, ἀποστέγεται, διὸ οὐ γίνεται δρόσος οὐδὲ πάχνη ὄντων ἐπινεφέλων.
But when it is cloudy, it is sheltered, which is why neither dew nor hoarfrost occurs when it is cloudy.
περὶ οὖν τὴν γῆν ὑπομένον τὸ θερμὸν ποιεῖ τὴν ἀλέαν.
Therefore, the heat remaining around the earth produces the warmth.
§25.22Διὰ τί ἐν τοῖς ὑψηλοῖς τῶν οἴκων ὁ ἀὴρ διευριπίζει, καὶ μάλιστα ταῖς εὐδίαις;
Why does the air fluctuate violently in the high parts of houses, and especially in calm weather?
ἢ διότι ὁ ἀὴρ πολύκενός τίς ἐστι τὴν σύγκρισιν.
Is it because the air is very porous in its composition?
ὅταν οὖν ἄρξηται εἴσω ῥεῖν, συγχωρεῖ ὁ ἐν τῷ οἰκήματι ἀὴρ καὶ συστέλλεται.
When, therefore, it begins to flow inward, the air in the room gives way and contracts.
τούτου δὲ συμπίπτοντος τῷ χρόνῳ πολυκενώτερος γίνεται ὁ ἔξωθεν.
When this falls together, in course of time the air outside becomes more porous.
καὶ χώραν πολλὴν ἴσχει.
And it occupies a large space.
εἰς ταύτην οὖν τὴν χώραν πίπτει ὁ ἐκ τοῦ οἰκήματος ἀήρ, ὢν πλησίον, καὶ φέρεται εἰς ταύτην τὴν χώραν διὰ τὸ κρέμασθαι καὶ τὴν τοῦ κενοῦ φύσιν μὴ δύνασθαι ἀντιστηρίζειν.
Therefore, the air from the room, being near, falls into this space, and is carried into this space because it is suspended and the nature of the void cannot support it.
κατὰ πολλὰ δὲ αὐτοῦ μέρη τούτου συμβαίνοντος, ἕπεται αὐτῷ ὁ πλησίον διὰ τὴν πρόσοψιν· εἶτα πολλοῦ ἔξωθεν φερομένου ὁ μὲν ἔσω τόπος πολύκενος γίνεται, ὁ δὲ ἔξω πυκνότερος, καὶ πάλιν ἔξωθεν εἴσω φέρεται.
And since this happens in many of its parts, the neighboring air follows it because of its appearance; then, as much air is carried outside, the place inside becomes very porous, and the outside denser, and again air is carried from the outside inward.
καὶ ταῦτα ἀλλάσσονται.
And these alternate.