All have numerous perforations, and there are passages broad and narrow in the interior of the earth, connecting them with one another; and there flows out of and into them, as into basins, a vast tide of water, and huge subterranean streams of perennial rivers, and springs hot and cold, and a great fire, and great rivers of fire, and streams of liquid mud, thin or thick (like the rivers of mud in Sicily, and the lava streams which follow them), and the regions about which they happen to flow are filled up with them. And there is a swinging or see-saw in the interior of the earth which moves all this up and down, and is due to the following cause:—There is a chasm which is the vastest of them all, and pierces right through the whole earth; this is that chasm 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 see-saw 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, but is swinging and surging 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 the act of respiration 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 in those regions,