Water clock, also called , was an instrument that recorded time by measuring water escaping from a vessel. Egyptians were using water clocks about 1400 B.C. People used it long before modern clocks were invented.
The water clock consisted of a container with a scale of markings on its side. These were so arranged that, as the water ran out, the water left in the jar marked the time. Various improvements were made in the device, such as having a floating figure point to the hour. Another design caused the dripping water to turn a small wheel that was connected to the hands on the face of a dial. The water clock was used in Rome as early as 159 B.C. It was used in Athens to regulate the length of speeches in the law courts.
