§1.12#2ὅτι μὲν οὖν οὐ τῷ ἀπωθεῖσθαι εἰς τὸν ἄνω τόπον τὸν ψυχρὸν ἡ πῆξις συμβαίνει, δῆλον· ἀλλʼ 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, ὥστʼ 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 ἐπαν έλθῃ φησὶ τοῦτο πάσχειν, ἡμεῖς δʼ ὅταν εἰς τὸν θερμὸν κατέλθῃ, καὶ μάλιστα ὅταν μάλιστα.
It is clear, then, that freezing does not occur by [the cloud] being thrust up into the cold upper region; but since we see that mutual repulsion (antiperistasis) occurs between heat and cold (which is why in warm weather the parts below the earth are cold, and in freezing weather they are warm), we must believe that this also occurs in the upper region, so that in the warmer seasons, the cold, being compressed inwards because of the surrounding warmth, sometimes quickly produces water from a cloud; wherefore also the drops are much larger on warm days than in winter, and the rains more violent; for rains are said to be more violent when they are more concentrated, and they are more concentrated because of the rapidity of the condensation. (This happens in the exact opposite way to what Anaxagoras says; for he says that this happens when [the cloud] rises up into the cold air, whereas we say it happens when it descends into the warm air, and especially when it is warmest.) But when the cold is even more compressed inwards by the heat outside, it freezes [the water] after having produced it, and hail occurs.
) ὅταν δʼ ἔτι μᾶλλον ἀντιπεριστῇ ἐντὸς τὸ ψυχρὸν ὑπὸ τοῦ ἔξω θερμοῦ, ὕδωρ ποιῆσαν ἔπηξεν καὶ γίγνεται χάλαζα. 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.
This happens when the freezing is faster than the downward movement of the water; for if it is carried down in such-and-such a time, but the cold, being intense, freezes it in less, nothing prevents it from freezing in the air, provided that the freezing occurs in a shorter time than the downward movement.
καὶ ὅσῳ δʼ ἂν ἐγγύτερον καὶ ἀθροωτέρα γένηται ἡ πῆξις, τά τε ὕδατα λαβρότερα γίγνεται καὶ αἱ ψακάδες καὶ αἱ χάλαζαι μείζους διὰ τὸ βραχὺν φέρεσθαι τόπον.
And the nearer and more concentrated the freezing occurs, the more violent the rains become, and both the drops and the hail become larger because of being carried over a short distance.
καὶ οὐ πυκναὶ αἱ ψακάδες αἱ μεγάλαι πίπτουσιν διὰ τὴν αὐτὴν αἰτίαν.
And large drops do not fall close together for the same reason.
ἧττον δὲ τοῦ θέρους γίγνεται ἢ ἔαρος καὶ μετοπώρου, μᾶλλ\ν μέντοι ἢ χειμῶνος, ὅτι ξηρότερος ὁ ἀὴρ τοῦ θέρους· ἐν δὲ τῷ ἔαρι ἔτι ὑγρός, ἐν δὲ τῷ μετοπώρῳ ἤδη ὑγραίνεται.
It occurs less in summer than in spring and autumn, but more than in winter, because the air is drier in summer; but in spring it is still moist, and in autumn it is already becoming moist.
γίγνονται δέ ποτε, καθάπερ εἴρηται, καὶ τῆς ὀπώρας χάλαζαι διὰ τὴν αὐτὴν αἰτίαν.
But sometimes, as has been said, hail also occurs in late summer for the same reason.
συμβάλλεται δʼ ἔτι πρὸς τὴν ταχυτῆτα τῆς πήξεως καὶ τὸ προτεθερμάνθαι τὸ ὕδωρ· θᾶττον γὰρ ψύχεται.
Furthermore, the fact that water has been previously warmed contributes to the rapidity of freezing; for it cools more quickly.
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 περιχέουσι τοῖς καλάμοις διὰ τὸ θᾶττον πήγνυσθαι· χρῶνται γὰρ τῷ κρυστάλλῳ ὥσπερ τῷ μολύβδῳ, ἵνʼ ἠρεμῶσιν οἱ κάλαμοι.
Therefore, many people, when they want to cool water quickly, place it in the sun first; and the people around the Pontus, when they build huts on the ice for the purpose of fishing (for they fish by cutting through the ice), pour warm water around their reeds so that it will freeze faster; for they use the ice like lead, in order that the reeds may remain steady.
θερμὸν δὲ γίγνεται ταχὺ τὸ συνιστάμενον ὕδωρ ἔν τε ταῖς χώραις καὶ ταῖς ὥραις ταῖς ἀλεειναῖς.
And the water that is condensing quickly becomes warm in warm countries and seasons.
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, ἢ γίγνεται διὰ τὸ ἀλεεινὴν εἶναι τὴν χώραν ἰσχυρῶς.
And rain occurs in Arabia and Ethiopia in summer and not in winter, and this is violent, and often on the same day, for the same reason; for it is quickly cooled by mutual repulsion (antiperistasis), or it occurs because the country is extremely warm.
περὶ μὲν οὖν ὑετοῦ καὶ δρόσου καὶ νιφετοῦ καὶ πάχνης καὶ χαλάζης, διὰ τίνʼ αἰτίαν γίγνεται καὶ τίς ἡ φύσις αὐτῶν ἐστιν, εἰρήσθω τοσαῦτα.
So, concerning rain, dew, snow, hoar-frost, and hail, as to what cause produces them and what their nature is, let so much be said.