The Hourglass

Not the flowing waters of time but the falling sands of time have given modern poets their favorite metaphor for the passing hours. In England, sandglasses were frequently placed in coffins as a symbol that life's time had run out. "The sands of time are sinking," went the hymn. "The dawn of heaven breaks." But the hourglass, measuring time by dripping sand, comes late in our story. Sand was, of course, less fluid than water, and hence less adapted to the subtle calibration required by the v...