One of the hollows of the earth, which is also the biggest, pierces through the whole earth; it is that which Homer mentioned when he said: “Far down where is the deepest pit below the earth . . .,”18 and which he elsewhere, and many other poets, call Tartarus; into this chasm all the rivers flow together, and again flow out of it, and each [b] river is affected by the nature of the land through which it flows.
