The ceaseless mutability of the created elements has been thus magnificently described:—

“For know, whatever was created needs

To be sustain’d and fed; of elements

The grosser feeds the purer, earth the sea,

Earth and the sea feed air, the air those fires

Ethereal, and as lowest first the Moon;

Whence in her visage round those spots, unpurg’d

Vapours not yet into her substance turn’d.

Nor doth the Moon no nourishment exhale

From her moist continent to higher orbs.