§4.5#2ἐὰν δὲ δύο, τὰ μεταξὺ πῶς ἔσται ποιοῦντα ἃ ποιεῖ ἀήρ τε καὶ ὕδωρ;
But if there are two, how will the intermediates act as air and water act?
οἷον εἴ τις φαίη εἶναι κενὸν καὶ πλῆρες.
As, for instance, if one should say that there are the void and the full.
τὸ μὲν οὖν πῦρ κενόν, διὸ ἄνω, τὴν δὲ γῆν πλῆρες, διὸ κάτω.
Fire indeed is the void, wherefore it is carried upward, and earth is the full, wherefore downward.
ἀέρα δὲ πλεῖον πυρὸς ἔχειν, ὕδωρ δὲ γῆς·
And air is said to have more of fire, and water of earth.
ἔσται γάρ τι ὕδωρ ὃ πλεῖον ἕξει πῦρ ὀλίγου ἀέρος, καὶ ἀὴρ πολὺς ὀλίγου ὕδατος γῆν πλείω, ὥστε δεήσει ἀέρος τι πλῆθος θᾶττον φέρεσθαι κάτω ὕδατος ὀλίγου.
For there will be some water which will have more fire than a small quantity of air, and a large quantity of air will have more earth than a small quantity of water; so that it will be necessary that some quantity of air is carried downward more quickly than a small quantity of water.
τοῦτο δʼ οὐ φαίνεται οὐδαμοῦ οὐδέποτε.
But this is never seen anywhere.
ἀνάγκη τοίνυν, ὥσπερ καὶ τὸ πῦρ ἄνω, ὅτι τοδὶ ἔχει, οἷον τὸ κενόν, τὰ δʼ ἄλλα οὔ, καὶ τὴν γῆν κάτω, ὅτι τὸ πλῆρες ἔχει, καὶ τὸν ἀέρα εἰς τὸν αὑτοῦ καὶ ἀνώτερον τοῦ ὕδατος, ὅτι τοδί τι ἔχει, καὶ τὸ ὕδωρ κάτω, ὅτι τοιόνδε τι.
It is necessary, therefore, just as fire is carried upward because it has this particular thing, such as the void, while the others do not, and earth is carried downward because it has the full, so also air is carried to its own place and above water because it has this particular thing, and water is carried downward because it has such a thing.
εἰ δὲ ἦν ἕν τι ἄμφω ἢ δύο, ἄμφω δʼ ὑπάρξει ταῦτα ἑκατέρω, ἔσται τι πλῆθος ἑκατέρου οὗ ὑπερέξει ὕδωρ τε ἀέρος ὀλίγου τῷ ἄνω καὶ ἀὴρ ὕδατος τῷ κάτω, καθάπερ εἴρηται πολλάκις.
But if there were some one thing for both or if there were two, and both of these belonged to each, there would be some quantity of each which water would exceed a small quantity of air in upward motion, and air would exceed water in downward motion, just as has been said many times.
Τὰ δὲ σχήματα οὐκ αἴτια τοῦ φέρεσθαι ἁπλῶς ἢ κάτω ἢ ἄνω, ἀλλὰ τοῦ θάττον ἢ βραδύτερον.
Shapes are not the causes of being carried simply either downward or upward, but of being carried more quickly or more slowly.
διʼ ἃς δʼ αἰτίας, οὐ χαλεπὸν ἰδεῖν·
Through what causes this is so is not difficult to see.
ἀπορεῖται γὰρ νύν διὰ τί τὰ πλατέα σιδήρια καὶ μόλιβδος ἐπιπλεῖ ἐπὶ τοῦ ὕδατος, ἄλλα δὲ ἐλάττω καὶ ἧττον βαρέα, ἂν ᾖ στρογγύλα ἢ μακρά, οἷον βελόνη, κάτω φέρεται, καὶ ὅτι ἔνια διὰ μικρότητα ἐπιπλεῖ, οἷον τὸ ψῆγμα καὶ ἄλλα γεώδη καὶ κονιορτώδη ἐπὶ τοῦ ἀέρος.
For it is now asked why flat pieces of iron and lead float upon water, while other things which are smaller and less heavy, if they are round or long, such as a needle, are carried downward; and why some things float because of their smallness, such as filings and other earthy and dusty things upon the air.
περὶ δὴ τούτων ἀπάντων τὸ μὲν νομίζειν αἴτιον εἶναι ὥσπερ Δημόκριτος οὐκ ὀρθῶς ἔχει.
Now, about all these things, it is not correct to think as Democritus did.
ἐκεῖνος γάρ φησι τὰ ἀναφερόμενα θερμὰ ἐκ τοῦ ὕδατος ἀνακωχεύειν τὰ πλατέα τῶν ἐχόντων βάρος, τὰ δὲ στενὰ διαπίπτειν· 313 b ὀλίγα γὰρ εἶναι τὰ ἀντικρούοντα αὐτοῖς.
For he says that the hot things rising up from the water support the flat ones of those having weight, but the narrow ones fall through, 313 b because the things resisting them are few.
ἔδει δʼ ἐν τῷ ἀέρι ἔτι μᾶλλον τοῦτο ποιεῖν, ὥσπερ ἐνίσταται κἀκεῖνος αὐτός.
But it would be necessary that this happens still more in the air, as indeed he himself objects.
ἀλλʼ ἐνστὰς λύει μαλακῶς· φησὶ γὰρ οὐκ εἰς ἓν ὁρμᾶν τὸν σοῦν, λέγων σοῦν τὴν κίνησιν τῶν ἄνω φερομένων σωμάτων.
But having objected, he solves it weakly; for he says that the rush (soūs) does not hasten in one direction, meaning by rush the motion of bodies carried upward.
ἐπεὶ δʼ ἐστὶ τὰ μὲν εὐδιαίρετα τῶν συνεχῶν τὰ δʼ ἧττον, καὶ διαιρετικὰ δὲ τὸν αὐτὸν τρόπον τὰ μὲν μᾶλλον τὰ δʼ ἧττον, ταύτας εἶναι νομιστέον αἰτίας.
But since some of continuous things are easily divided and others less so, and the dividing things are in the same way some more and others less so, these must be considered the causes.
εὐδιαίρετον μὲν οὖν τὸ εὐόριστον, καὶ μᾶλλον τὸ μᾶλλον· ἀὴρ δὲ μᾶλλον ὕδατος τοιοῦτον, ὕδωρ δὲ γῆς.
Now, that which is easily divided is that which is easily bounded, and the more so, the more it is so; and air is more of such a kind than water, and water than earth.
καὶ τὸ ἔλαττον δὴ ἐν ἑκάστῳ γένει εὐδιαιρετώτερον καὶ διασπᾶται ῥᾷον.
And indeed the smaller in each class is more easily divided and more easily rent.
τὰ μὲν οὖν ἔχοντα πλάτος διὰ τὸ πολὺ περιλαμβάνειν ἐπιμένει, διὰ τὸ μὴ διασπᾶσθαι τὸ πλεῖον ῥᾳδίως· τὰ δʼ ἐναντίως ἔχοντα τοῖς σχήμασι διὰ τὸ ὀλίγον περιλαμβάνειν φέρεται κάτω, διὰ τὸ διαιρεῖν ῥᾳδίως.
Therefore, things having breadth remain on the surface because they enclose much, since a larger quantity is not easily rent; while those which are contrary in shape, because they enclose little, are carried downward, because they divide easily.
καὶ ἐν ἀέρι πολύ μᾶλλον, ὅσῳ εὐδιαιρετώτερος ὕδατός ἐστιν.
And in the air much more so, in proportion as it is more easily divided than water.
ἐπεὶ δὲ τό τε βάρος ἔχει τινὰ ἰσχὺν καθʼ ἣν φέρεται κάτω, καὶ τὰ συνεχῆ πρὸς τὸ μὴ διασπᾶσθαι, ταῦτα δεῖ πρὸς ἄλληλα συμβάλλειν· ἐὰν γὰρ ὑπερβάλλῃ ἡ ἰσχὺς ἡ τοῦ βάρους τῆς ἐν τῷ συνεχεῖ πρὸς τὴν διάσπασιν καὶ διαίρεσιν, βιάσεται κάτω θᾶττον, ἐὰν δὲ ἀσθενεστέρα ᾖ, ἐπιπολάσει.
But since both heaviness has a certain force by which it is carried downward, and continuous things have a force to resist being rent, these must be compared with one another; for if the force of the heaviness exceeds that of the continuous thing to resist being rent and divided, it will force its way downward more quickly, but if it is weaker, it will float.
περὶ μὲν οὖν βαρέος καὶ κούφου καὶ τῶν περὶ αὐτὰ συμβεβηκότων διωρίσθω τοῦτον ἡμῖν τὸν τρόπον.
Concerning, then, the heavy and the light, and the properties associated with them, let them be defined by us in this manner.