by Percy Bysshe Shelley
We are as clouds that veil the midnight moon;
How restlessly they speed, and gleam, and quiver,
Streaking the darkness radiantly!—yet soon
Night closes round, and they are lost for ever:
Or like forgotten lyres, whose dissonant strings
Give various response to each varying blast,
To whose frail frame no second motion brings
One mood or modulation like the last.
We rest.—A dream has power to poison sleep;
We rise.—One wandering thought pollutes the day;
We feel, conceive or reason, laugh or weep;
Embrace fond woe, or cast our cares away:
It is the same!—For, be it joy or sorrow,
The path of its departure still is free:
Man's yesterday may ne'er be like his morrow;
Nought may endure but Mutability.
This poem is quoted and alluded to several times in Mary Shelley's Frankenstein.