Let us, if you please, go into the matter a little more deeply, and 1 you will soon see that you have no cause to put further questions, once you reach the true origin of rivers. A river is, of course, formed by a supply of water that is always constant. If you ask me, therefore, how water is produced, I will ask in my turn how air or earth is produced. If there are four elements in nature, you are not entitled to ask where water, one of them, comes from; it _is_ the fourth part of nature. Why, therefore, are you surprised that so great a portion 2 of nature can furnish a perpetual supply of liquid from itself? Just as the atmosphere, which is likewise a fourth part of the universe, is the source of winds and breezes, so is water, of streams and rivers. If wind is atmosphere in motion, so is a river water in motion. I have given it strength enough in saying that it is one of the four elements. You must be aware that what has an element as its source can never run short. XIII Water is, according to Thales, the most powerful of the elements. 1 He thinks it was the first of them, and that all the others sprang from it. We Stoics, too, are also of the same opinion; or perhaps I should rather say that we think it is the last.[54] For we say that it is fire that lays hold upon the world and changes all things into its own nature. We suppose that fire eventually fades and sinks, and that, when the fire is quenched, nothing is left in nature save moisture, in which lies the hope of the world that is to come. So fire is the end, moisture the beginning, of the world. Can you wonder that rivers may always issue from this, which was before all things, and from which all things have been formed? In the separation of the elements [at the 2 beginning] the moisture was reduced to a fourth part, and was placed in such a situation that it could furnish a sufficient supply for rivers, streams, and fountains. The next opinion expressed by Thales is a silly one. The whole earth, he says, is upborne by water, and floats just like a boat; when it is spoken of as trembling, it is rolling by the movement of the water. It is no wonder, then, that there should be abundance of water to pour forth in rivers, since the world is itself wholly set in water. You should put out of court such an antiquated, unscientific idea. There is no ground for believing that the water comes in through the chinks in the earth’s sides, and forms bilge-water in her centre. [54] _I.e._ that to which all others may be reduced: the text seems corrupt, and the meaning is more or less conjectural. Gercke’s text reads, “are also of the same or an analogous opinion.” XIV