N the next place we have to consider that there are divers kinds of fire. There are, for example, first, flame; and secondly, those emanations of flame which do not burn but only give light to the eyes; thirdly, the remains of fire, which are seen in red-hot embers after the flame has been extinguished. There are similar differences in the air; of which the brightest part is called the aether, and the most turbid sort mist and darkness; and there are various other nameless kinds which arise from the inequality of the triangles. Water, again, admits in the first place of a division into two kinds; the one liquid and the other fusile. The liquid kind is composed of the small and unequal particles of water; and moves itself and is moved by other bodies owing to the want of uniformity and the shape of its particles; whereas the fusile kind, being formed of large and uniform particles, is more stable than the other, and is heavy and compact by reason of its uniformity. But when fire gets in and dissolves the particles and destroys the uniformity, it has greater mobility, and becoming fluid is thrust forth by the neighbouring air and spreads upon the earth; and this dissolution of the solid masses is called melting, and their spreading out upon the earth flowing. Again, when the fire goes out of the fusile substance, it does not pass into vacuum, but into the neighbouring air; and the air which is displaced forces together the liquid and still moveable mass into the place which was occupied by the fire, and unites it with itself. Thus compressed the mass resumes its equability, and is again at unity with itself, because the fire which was the author of the inequality has retreated; and this departure of the fire is called cooling, and the coming together which follows upon it is termed congealment.

γενῶν εἴδη

Μετὰ δὴ ταῦτα δεῖ νοεῖν ὅτι πυρός τε γένη πολλὰ γέγονεν͵ οἷον φλὸξ τό τε ἀπὸ τῆς φλογὸς ἀπιόν͵ ὃ κάει μὲν οὔ͵ φῶς δὲ τοῖς ὄμμασιν παρέχει͵ τό τε φλογὸς ἀποσβεσθείσης ἐν τοῖς διαπύροις καταλειπόμενον αὐτοῦ· [58d] κατὰ ταὐτὰ δὲ ἀέρος͵ τὸ μὲν εὐαγέστατον ἐπίκλην αἰθὴρ καλούμενος͵ ὁ δὲ θολερώτατος ὁμίχλη τε καὶ σκότος͵ ἕτερά τε ἀνώνυμα εἴδη͵ γεγονότα διὰ τὴν τῶν τριγώνων ἀνισότητα. τὰ δὲ ὕδατος διχῇ μὲν πρῶτον͵ τὸ μὲν ὑγρόν͵ τὸ δὲ χυτὸν γένος αὐτοῦ. τὸ μὲν οὖν ὑγρὸν διὰ τὸ μετέχον εἶναι τῶν γενῶν τῶν ὕδατος ὅσα σμικρά͵ ἀνίσων ὄντων͵ κινητικὸν αὐτό τε καθ΄ αὑτὸ καὶ ὑπ΄ ἄλλου διὰ τὴν ἀνωμαλότητα καὶ τὴν τοῦ σχήματος ἰδέαν γέγονεν· [58e] τὸ δὲ ἐκ μεγάλων καὶ ὁμαλῶν στασιμώτερον μὲν ἐκείνου καὶ βαρὺ πεπηγὸς ὑπὸ ὁμαλότητός ἐστιν͵ ὑπὸ δὲ πυρὸς εἰσιόντος καὶ διαλύοντος αὐτὸ τὴν ὁμαλότητα ἀποβάλλει͵ ταύτην δὲ ἀπολέσαν μετίσχει μᾶλλον κινήσεως͵ γενόμενον δὲ εὐκίνητον͵ ὑπὸ τοῦ πλησίον ἀέρος ὠθούμενον καὶ κατατεινόμενον ἐπὶ γῆν͵ τήκεσθαι μὲν τὴν τῶν ὄγκων καθαίρεσιν͵ ῥοὴν δὲ τὴν κατάτασιν ἐπὶ γῆν ἐπωνυμίαν ἑκατέρου τοῦ πάθους ἔλαβεν. [59a] πάλιν δ΄ ἐκπίπτοντος αὐτόθεν τοῦ πυρός͵ ἅτε οὐκ εἰς κενὸν ἐξιόντος͵ ὠθούμενος ὁ πλησίον ἀὴρ εὐκίνητον ὄντα ἔτι τὸν ὑγρὸν ὄγκον εἰς τὰς τοῦ πυρὸς ἕδρας συνωθῶν αὐτὸν αὑτῷ συμμείγνυσιν· ὁ δὲ συνωθούμενος ἀπολαμβάνων τε τὴν ὁμαλότητα πάλιν͵ ἅτε τοῦ τῆς ἀνωμαλότητος δημιουργοῦ πυρὸς ἀπιόντος͵ εἰς ταὐτὸν αὑτῷ καθίσταται. καὶ τὴν μὲν τοῦ πυρὸς ἀπαλλαγὴν ψῦξιν͵ τὴν δὲ σύνοδον ἀπελθόντος ἐκείνου πεπηγὸς εἶναι γένος προσερρήθη.