Ariel, in Shakespeare's Tempest, one of the spirits of the air, where, liberated from the tyranny of Sycorax and Caliban, he gratefully and loyally serves Prospero for sixteen years as a benign supernatural agency. Pope in The Rape of the Loch makes use of the same conception. Milton (Paradise Lost, vi. 371) introduces us to a fallen angel of this name. Isaiah (xxix. 1-7) used the word in speaking of Jerusalem, and in this sense it has been explained to mean either "lion of God" or "hearth of God."