Where light and darkness in perpetual round

Lodge and dislodge by turns, which makes through heaven

Grateful vicissitude, like day and night:

Light issues forth, and at the other door

Obsequious darkness enters, till her hour

To veil the heaven.

[219] Sleep, Death’s half brother.] Virg. Æn. vi. 278:

Here Toils and Death, and Death’s half-brother Sleep,

Forms terrible to view, their sentry keep.

Dryden.