Time Standard of the Dark Ages: The H2O
Water clocks were among the earliest timekeepers
that didn't depend on the observation of celestial bodies. One of the
oldest was found in the tomb of Amenhotep I, buried around 1500 B.C.
Later named clepsydras ("water thief") by the Greeks, who began using
them about 325 B.C., these were stone vessels with sloping sides that
allowed water to drip at a nearly constant rate from a small hole near
the bottom. Markings on the inside surfaces measured the passage of
"hours" as the water level reached them. These clocks were used to determine
hours at night, but may have been used in daylight as well.