Page:Early Greek philosophy by John Burnet, 3rd edition, 1920.djvu/243

Rh confusion with what had hitherto been meant by the former word. He had, in fact, made the discovery that atmospheric air is a distinct corporeal substance, and is not to be identified with empty space on the one hand or rarefied mist on the other. Water is not liquid air, but something quite different. This truth Empedokles demonstrated by means of the klepsydya, and we still possess the verses in which he applied his discovery to the explanation of respiration and the motion of the blood (fr. 100). Aristotle laughs at those who try to show there is no empty space by shutting up air in water-clocks and torturing wineskins. They only prove, he says, that air is a thing. That, however, is exactly what Empedokles intended to prove, and it was one of the most important discoveries in the history of science. It will be convenient for us to translate the αἰθήρ Empedokles by "air"; but we must be careful in that case not to render the word ἀήρ in the same way. Anaxagoras seems to have been the first to use it of atmospheric air.

Empedokles also called the "four roots" by the names of certain divinities—"shining Zeus, life-bringing Hera, Aidoneus, and Nestis" (fr. 6)—though there is some doubt as to how these names are to be apportioned among the elements. Nestis is said to have been a Sicilian water-goddess, and the description of her shows that she stands for Water; but there is a conflict of opinion as to the other three. This, however, need not detain us. We are