What were water clocks?

Answer 1

"Throughout history, time has been measured by the movement of the earth in relation to the sun and stars. The earliest timekeeper dating from as far back as 3500 BC was the shadow clock, or gnomon, a vertical obelisk that cast a shadow. Devices almost as old as the shadow clock and sundial include the hourglass (in which the flow of sand is used to measure time intervals) and the water clock or clepsydra, in which the flow of water indicates passage of time. All time-pieces require a source of power and a means of transmitting and controlling it. In today's clocks the source of power may be produced by weights, a coiled spring or an electric current. The huge planetary clock-type models, driven by water that originated during the 13th century and discovered in China, the Middle East and North America are considered to be the forerunners of today's mechanical clocks. Eventually a weight falling under the force of gravity was substituted for the flow of water. Although the exact origin of this mechanical device remains a mystery to this day, the first recorded examples date from the 14th century. An original medieval clock dating from 1386 has been fully restored and can be seen at Salisbury Cathedral in England. These clocks were not very accurate and would loose up to 15 minutes a day!" FROM www.holtzhausen.com

Answer 2

A water clock or clepsydra (Greek kleptein, to steal; hydro, water) is any timekeeper operated by means of a regulated flow of liquid into (inflow type) or out from (outflow type) a vessel where the amount is then measured. Water clocks, along with sundials, are likely to be the oldest time-measuring instruments, with the only exceptions being the vertical gnomon and the day-counting tally stick.[1] Given their great antiquity, where and when they first existed are not known and may be unknowable. The bowl-shaped outflow is the simplest form of a water clock and is known to have existed in Babylon and in Egypt around the 16th century BC. Other regions of the world, including India and China, also have early evidence of water clocks, but the earliest dates are less certain. Some authors, however, write about water clocks appearing in China as early as 4000 BC.[2] The Greek and Roman civilizations are credited for initially advancing water clock design to include the inflow clepsydra with the earliest feedback system and complex gearing, which was connected to fanciful automata and also resulted in improved accuracy. These advances were passed on through Byzantium and Islamic times, eventually making their way to Europe. Independently, the Chinese developed their own advanced water clocks, passing their ideas on to Korea and Japan. Some water clock designs were developed independently and some knowledge was transferred through the spread of trade. It is important to point out that the need for the common person to 'know what time it is' largely did not exist until the Industrial Revolution, when it became important to keep track of hours worked. In the earliest of times, however, the water clocks were mainly used for astronomical and astrological purposes. These early water clocks were calibrated with a sundial. Through the centuries, water clocks were used for timing lawyer's speeches during a trial, labors of prostitutes, night watches of guards, sermons and Masses in church, to name only a few.[citation needed] While never reaching a level of accuracy comparable to today's standards of timekeeping, the water clock was the most accurate and commonly used timekeeping device for millennia, until it was replaced by more accurate pendulum clocks in 18th century Europe.

SOURCES: WWW.WIKIPEDIA.COM