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Sundial first used in Egypt
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Greeks use a water clock
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King Charles V of France decrees that all Paris church bells must ring at the same time as the Royal Palace, helping end the ringing of bells at prayer time decreed by the church.
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The mechanical clocks are built in Europe, using a mainspring and balance wheel.
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Galileo Galilei realizes that the frequency of a pendulum's swing depends on its length.
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Christiaan Huygens invents the first pendulum clock, capable of far greater accuracy than any preceding timekeeper. But the clock does not work at sea.
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John Harrison builds a clock, that loses only 5 seconds on a voyage from England to Jamaica.
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Telegraph invented, allowing instant transmission of time signals.
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Time ball is dropped at noon each day at the U.S. Naval Observatory. Ships in the harbor use the ball to set their clocks.
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Twenty-five countries accept Greenwich, England, as the prime meridian (0 degrees longitude). The prime meridian gradually becomes the basis for time throughout the world.
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Salespeople for the R.W. Sears Watch Company fan out across America selling affordable timepieces. The firm is later renamed Sears, Roebuck and Co.
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A radio time signal starts being transmitted from Washington DC to help ships find longitude.
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Time is more popular than ever: about half-a-billion watches are sold each year.
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Alfred the Great uses burning candles to measure time.