Time passing;Discovery Series

13th August 1999 at 01:00
How the face of time has changed

c2000 BC First Egyptian shadow clocks and water clocks appear

45 BC Julian Calendar introduced. Revised by Pope Gregory XIII in 1582 and became today's calendar. Adopted by this country in 1752

1283 First mechanical clock said to have been built at Dunstable Priory

1392 Wells Cathedral clock built

1657 First pendulum patented

1762 John Harrison's fourth chronometre solves the 50-year-old challenge to find longitude

1884 International Meridian Treaty signed

1905 Radio time signal transmitted by telegraph from Boston

1923-24 First "pips" and sound of Big Ben broadcast by the BBC

to usher in the new year

1929 First quartz clock

1955 First atomic clock built

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