Water thief

Clepsydra or Klepshydra (Greek κλεψύδρα " water thief " ) referred to a common water clock in ancient Greece.

Function

A clepsydra consists of two containers. From the water-filled container outlet, the water flows into a lead container. The water level in the inlet reservoir shows the elapsed time. This principle after it is the sand-glass; both are made of two containers, flow "particles" between. This particle is related to the passage of time.

Later versions were built with gear drives that were connected to a float. These are a precursor to the modern clock.

Origin

Like the other major instruments in ancient Greece ( gnomon and polos ) it comes from the Middle East.

Use

In ancient Greece it was used not only for measuring the hours in general, but particularly to limit the speaking time of the contending parties before the court. However, they did not find in all kinds of processes application.

The clepsydra could have different designs. Some were a siphon, so a large pipette, similar. This is a pitcher- like vessel which is narrower toward the top. On the upper side has a larger opening at the bottom of many small holes. To draw water, the clepsydra is dipped into the water, locked the top opening and lifted the water-filled instrument out of the water. In the belly of the vessel is water that can be transported to any location.

With such a clepsydra has the Greek Anaxagoras by simple experiments in the context of its results, according to today's perspective, erroneously, the non-existence of empty space after. In the first experiment the clepsydra with closed upper opening is pushed into the water, so that no water can penetrate into the clepsydra; in the second experiment, the water-filled and sealed up clepsydra is carried out of the water. The first attempt suggests Anaxagoras as pressure of a substance in the clepsydra, which prevents the penetration of water into the vessel. For the Nichtausdringen the water from the clepsydra in the second experiment Anaxagoras blames the pressure of a material space outside of the vessel. These and similar experiments with the clepsydra were popular with the pre-Socratics.

Others

In the Moroccan Klepsydra the smaller containers in the middle has a small hole. As soon as he sinks into the larger container, a defined time period has elapsed.

In the Polish language klepsydra appoint an hourglass, but also an obituary notice.