The first clock powered by changes in atmospheric pressure and temperature was invented by
Cornelis Drebbel in the early 17th century. Drebbel built as many as 18 of these, the two most notable being for King
James VI & I of Britain, and
Rudolf II of Bohemia. The King James clock was known as the Eltham Perpetuum, and was famous throughout Europe. It is mentioned in two works of
Ben Jonson. Clocks powered by atmospheric pressure and temperature changes were subsequently developed by
Pierre de Rivaz in 1740, On 1 June 1929, Compagnie Générale de Radio (CGR) in France began manufacturing the first commercial model, Atmos 1, which used a mercury and
ammonia bellows power source. On 27 July 1935, Jaeger-LeCoultre took over production of Atmos 1 while it developed a second design which used the present ethyl chloride power source. This model later named the Atmos 2, was announced on 15 January 1936, but problems delayed full production until mid-1939. Subsequent models were based on this design. To date, over 500,000 Atmos clocks have been produced. ==See also==