And there is a sort of swing in the interior of the earth which moves all this up and down. Now the swing is in this wise: There is a chasm which is the vastest of them all, and pierces right through the whole earth; this is that which Homer describes in the words, - "Far off, where is the inmost depth beneath the earth"; - and which he in other places, and many other poets, have called Tartarus. And the swing is caused by the streams flowing into and out of this chasm, and they each have the nature of the soil through which they flow. And the reason why the streams are always flowing in and out is that the watery element has no bed or bottom, and is surging and swinging up and down, and the surrounding wind and air do the same; they follow the water up and down, hither and thither, over the earth-just as in respiring the air is always in process of inhalation and exhalation; and the wind swinging with the water in and out produces fearful and irresistible blasts: when the waters retire with a rush into the lower parts of the earth, as they are called, they flow through the earth into those regions, and fill them up as with the alternate motion of a pump, and then when they leave those regions and rush back hither, they again fill the hollows here, and when these are filled, flow through subterranean channels and find their way to their several places, forming seas, and lakes, and rivers, and springs. Thence they again enter the earth, some of them making a long circuit into many lands, others going to few places and those not distant, and again fall into Tartarus, some at a point a good deal lower than that at which they rose, and others not much lower, but all in some degree lower than the point of issue. And some burst forth again on the opposite side, and some on the same side, and some wind round the earth with one or many folds, like the coils of a serpent, and descend as far as they can, but always return and fall into the lake. The rivers on either side can descend only to the center and no further, for to the rivers on both sides the opposite side is a precipice.

ταῦτα δὲ πάντα κινεῖν ἄνω καὶ κάτω ὥσπερ αἰώραν τινὰ ἐνοῦσαν ἐν τῇ γῇ· ἔστι δὲ ἄρα αὕτη ἡ αἰώρα διὰ φύσιν τοιάνδε τινά. ἕν τι τῶν χασμάτων τῆς γῆς ἄλλως τε μέγιστον τυγχάνει ὂν καὶ διαμπερὲς τετρημένον δι΄ ὅλης τῆς γῆς͵ τοῦτο ὅπερ Ὅμηρος εἶπε͵ λέγων αὐτό τῆλε μάλ΄͵ ᾗχι βάθιστον ὑπὸ χθονός ἐστι βέρεθρον· ὃ καὶ ἄλλοθι καὶ ἐκεῖνος καὶ ἄλλοι πολλοὶ τῶν ποιητῶν Τάρταρον κεκλήκασιν. εἰς γὰρ τοῦτο τὸ χάσμα συρρέουσί τε πάντες οἱ ποταμοὶ καὶ ἐκ τούτου πάλιν ἐκρέουσιν· γίγνονται δὲ ἕκαστοι τοιοῦτοι δι΄ οἵας ἂν καὶ τῆς γῆς ῥέωσιν. ἡ δὲ αἰτία ἐστὶν τοῦ ἐκρεῖν τε ἐντεῦθεν καὶ εἰσρεῖν πάντα τὰ ῥεύματα͵ ὅτι πυθμένα οὐκ ἔχει οὐδὲ βάσιν τὸ ὑγρὸν τοῦτο. αἰωρεῖται δὴ καὶ κυμαίνει ἄνω καὶ κάτω͵ καὶ ὁ ἀὴρ καὶ τὸ πνεῦμα τὸ περὶ αὐτὸ ταὐτὸν ποιεῖ· συνέπεται γὰρ αὐτῷ καὶ ὅταν εἰς τὸ ἐπ΄ ἐκεῖνα τῆς γῆς ὁρμήσῃ καὶ ὅταν εἰς τὸ ἐπὶ τάδε͵ καὶ ὥσπερ τῶν ἀναπνεόντων ἀεὶ ἐκπνεῖ τε καὶ ἀναπνεῖ ῥέον τὸ πνεῦμα͵ οὕτω καὶ ἐκεῖ συναιωρούμενον τῷ ὑγρῷ τὸ πνεῦμα δεινούς τινας ἀνέμους καὶ ἀμηχάνους παρέχεται καὶ εἰσιὸν καὶ ἐξιόν. ὅταν τε οὖν ὑποχωρήσῃ τὸ ὕδωρ εἰς τὸν τόπον τὸν δὴ κάτω καλούμενον͵ τοῖς κατ΄ ἐκεῖνα τὰ ῥεύματα [διὰ] τῆς γῆς εἰσρεῖ τε καὶ πληροῖ αὐτὰ ὥσπερ οἱ ἐπαντλοῦντες· ὅταν τε αὖ ἐκεῖθεν μὲν ἀπολίπῃ͵ δεῦρο δὲ ὁρμήσῃ͵ τὰ ἐνθάδε πληροῖ αὖθις͵ τὰ δὲ πληρωθέντα ῥεῖ διὰ τῶν ὀχετῶν καὶ διὰ τῆς γῆς͵ καὶ εἰς τοὺς τόπους ἕκαστα ἀφικνούμενα͵ εἰς οὓς ἑκάστοις ὡδοποίηται͵ θαλάττας τε καὶ λίμνας καὶ ποταμοὺς καὶ κρήνας ποιεῖ· ἐντεῦθεν δὲ πάλιν δυόμενα κατὰ τῆς γῆς͵ τὰ μὲν μακροτέρους τόπους περιελθόντα καὶ πλείους͵ τὰ δὲ ἐλάττους καὶ βραχυτέρους͵ πάλιν εἰς τὸν Τάρταρον ἐμβάλλει͵ τὰ μὲν πολὺ κατωτέρω ἢ ᾗ ἐπηντλεῖτο͵ τὰ δὲ ὀλίγον· πάντα δὲ ὑποκάτω εἰσρεῖ τῆς ἐκροῆς͵ καὶ ἔνια μὲν καταντικρὺ ἢ ᾗ [εἰσρεῖ] ἐξέπεσεν͵ ἔνια δὲ κατὰ τὸ αὐτὸ μέρος· ἔστι δὲ ἃ παντάπασιν κύκλῳ περιελθόντα͵ ἢ ἅπαξ ἢ καὶ πλεονάκις περιελιχθέντα περὶ τὴν γῆν ὥσπερ οἱ ὄφεις͵ εἰς τὸ δυνατὸν κάτω καθέντα πάλιν ἐμβάλλει. δυνατὸν δέ ἐστιν ἑκατέρωσε μέχρι τοῦ μέσου καθιέναι͵ πέρα δ΄ οὔ· ἄναντες γὰρ ἀμφοτέροις τοῖς ῥεύμασι τὸ ἑκατέρωθεν γίγνεται μέρος.