Although early methods were surprisingly accurate for measuring long amounts of time eventually man needed to know how to determine the short periods. Water clocks measure time based on how much water flows from one container to the next. The so called tower of winds in athens built in the early first century bc is a marvel of engineering containing both sun dials about which more in a future post and a water clock inside.
A water clock is a timekeeping device that uses a flow of water to measure time.
Water clocks became a common method of telling time in the ancient world. A water clock or clepsydra greek κλεψύδρα from κλέπτειν kleptein to steal. Clepsydra also called water clock ancient device for measuring time by the gradual flow of water one form used by the north american indians and some african peoples consisted of a small boat or floating vessel that shipped water through a hole until it sank. The clepsydra or water clock dates back to 1500 bc and was once a valuable time tracking tool used in various ancient societies.