what device did the chinese invent to keep track of time?
Outflow and inflow clepsydra
History of timekeeping devices
Joseph Needham speculated that the introduction of the outflow clepsydra to China, perhaps from Mesopotamia, occurred as far back as the 2nd millennium, during the Shang Dynasty, and at the latest by the 1st millennium. By the beginning of the Han Dynasty, in 202, the outflow clepsydra was gradually replaced by the inflow clepsydra, which featured an indicator rod on a float. 
who invented the first mechanical clock in 1300 Catholic monks which of the earliest civilizations used timekeeping devices? Hunter-gatherers, Prehistoric Europe, Mesoamericans, etc why did the monks invent the clock? To regulate daily prayer- and work-schedules strictly and to ensure accuracy can you give me examples of timekeeping devices? Astronomical bodies, sticks and bones to track the phases of the moon or the seasons, Stone circles, sexagesimal timekeeping, and vigesimal counting system name some of the innovations during the medieval period Clock, wristwatches, Clock of the Long Now, mechanical clock, and pendulum clock did ancient egypt use timekeeping devices? Yes, Shadow clocks and Sundials what about greece? They used water clocks, or clepsydrae, and water-based alarm clock name some of the innovations during the pre-modern period Mechanical clocks and pendulum clock is it possible to keep track of time underwater? Yes, by Marine chronometers how did the persians keep track of time? By using water clocks
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History of timekeeping devices [SEP] Ancient and medieval China
Joseph Needham speculated that the introduction of the outflow clepsydra to China, perhaps from Mesopotamia, occurred as far back as the 2nd millennium, during the Shang Dynasty, and at the latest by the 1st millennium. By the beginning of the Han Dynasty, in 202, the outflow clepsydra was gradually replaced by the inflow clepsydra, which featured an indicator rod on a float. To compensate for the falling pressure head in the reservoir, which slowed timekeeping as the vessel filled, Zhang Heng added an extra tank between the reservoir and the inflow vessel. Around 550 AD, Yin Gui was the first in China to write of the overflow or constant-level tank added to the series, which was later described in detail by the inventor Shen Kuo.