That hour-glass which there you see
With water fill'd, sirs, credit me,
The humour was, as I have read,
But lovers' tears incrystalled.
Which, as they drop by drop do pass
From th' upper to the under-glass,
Do in a trickling manner tell,
By many a watery syllable,
That lovers' tears in lifetime shed
Do restless run when they are dead.

Robert Herrick

http://www.poemhunter.com/poem/the-hour-glass/