VI
Well, then, I take it, in water there resides some vital principle. In water, did I say? Why, fire, the universal destroyer, has a creative function; it may not seem a likely thing, but all the same it is but the truth that some animals are generated by fire. The atmosphere, then, possesses some power of this kind; and that is why it sometimes grows thick, sometimes expands and throws off impurities, sometimes contracts, at others opens up and disperses. There is thus the same difference between air and wind as between lake and river.72 There are occasions when the sun is the sole cause of wind, as he rarefies the stiff atmosphere and opens it out from its thick contracted state.