Let us begin with the beginning and creation of the whole universe, which Thales the Milesian refers to the substance water, and let us see whether Homer first discovered this when he said (I. xiv. 246):—
Even to the stream of old Oceanus Prime origin of all.
After him Xenophanes of Colophon, laying down that the first elements were water and land, seems to have taken this conception from the Homeric poems (I. vii. 99):—
To dust and water turn all ye who here inglorious sit.
For he indicates their dissolution into the original elements of the universe. But the most likely opinion makes four elements,—fire, air, water, earth. These Homer shows he knows, as in many places he makes mention of them.
He knew, too, the order of their arrangement. We shall see that the land is the lowest of them all, for as the world is spherical, the sky, which contains all things, can reasonably be said to have the highest position. The earth being in the midst everywhere is below what surrounds it. This the poet declares chiefly in the lines where he says if Zeus let a chain down from Olympus, he could turn over the land and sea so that everything would be in the air (I. viii. 23):—
But if I choose to make my pow'r be known,
The earth itself and ocean I could raise,
And binding round Olympus' ridge the cord
Leave them suspended so in middle air.
Although the air is around the earth, he says the ether is higher in the following lines (I. xiv. 287):—
And going up on a lofty pine, which then grew on the summit
of Ida and through the air reached into the ether.
But higher than the ether is heaven (I. xvii. 424):—