And thus they fought: the iron clangor pierc'd
The airless ether and brazen vault of Heaven.
And, besides, in the following (I. i. 497):—
The vapor ascended to the great heaven and to Olympus.
The top part of the air is finer and more distant from the earth and its exhalations. Therefore it is said Olympus is called "wholly shining." Where the poet says Hera is the wife of Zeus, although she is his sister, he seems to speak in an allegory, since Hera stands for the air, which is a humid substance. Therefore he says (I. xxi. 6):—
Hera spread before their path clouds of thick darkness.
By Zeus is signified the ether, that is the fiery and heated substance (I. xv. 192):—
Broad Heav'n amid the sky and clouds, to Jove.
They seem brother and sister on account of a certain likeness and relationship, because both are light and mobile; they dwell together and are intimate, because from their intercourse all things are generated. Therefore they meet in Ida, and the land produces for them plants and flowers.
The same explanation have those words in which Zeus says he will, hang Hera and fasten two weights to her feet, namely, the land and the sea. He works out especially the principles of the elements in what Poseidon says to him (I. xv. 187):—
We were brethren, all of Rhaea born
To Saturn: Jove and I and Pluto third,
Who o'er the nether regions holds his sway,