35 Mantel202 A mid 20th century Atmos clock by Jaeger le Coultre. #39751. It runs and is original and complete, but not recently overhauled. In 1928 a Neuchatel engineer called Jean-Leon Reutter built a clock driven quite literally by air. But it took the Jaeger-LeCoultre workshop a few more years to convert this idea into a technical form that could be patented. And to perfect it to such a degree that the Atmos practically achieved perpetual motion. In 1936 the Manufacture began production of the Atmos. The technical principle is a beguiling one: inside a hermetically sealed capsule is a mixture of gas and liquid (ethyl chloride) which expands as the temperature rises and contracts as it falls, making the capsule move like a concertina. This motion constantly winds the mainspring, a variation in temperature of only one degree in the range between 15 and 30 degrees centigrade being sufficient for two days' operation. To convert this small amount of energy into motion, everything inside the Atmos naturally has to work as smoothly and quietly as possible. The balance, for example, executes only two torsional oscillations per minute, which is 150 times slower that the pendulum in a conventional clock. So it's not surprising that 60 million Atmos clocks together consume no more energy that one 15-watt light bulb. All its other parts, too, are not only of the highest precision, but also practically wear-free. An Atmos can therefore expect to enjoy a service life of a good 600 years, although with today's air pollution we regrettably have to recommend a through cleaning every 20 years or so. Admirers of advanced technology, however, aren't the only ones who get their money's worth. Connoisseurs of elegant forms, precious materials and traditional craftsmanship, do so as well. Because every Atmos is still made entirely by hand; and with some models a single clock takes a whole month to produce. Not counting the five weeks of trial and adjustment that every Atmos has to undergo. Only then, are the Jaeger-LeCoultre master-watchmakers happy enough with the state of things to confirm it with a signature and allow another Atmos to leave the workshop. After which, many end up in the very best homes, because for decades now the world's most celebrated watch-making country has been presenting its distinguished guests with this masterpiece of Swiss artistry. The Atmos has had the honour to be associated with great statesmen, royalty, and other renowned people including John F. Kennedy, Sir Winston Churchill, General Charles De Gaulle, and Charlie Chaplin. http://www.jaeger-lecoultre.com/collection/atmos/atmos.html