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
