i2 4 PHYSICAL SCIENCE BK. HI 



2 from ; it is the fourth part of nature. Why, there- 

 fore, are you surprised that so great a portion 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 



1 WATER is, according to Thales, the most powerful 

 of the elements. 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. 1 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 



2 formed? In the separation of the elements [at 

 the 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 



1 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." 



