Atmos watch by Jaeger- LeCoultre, Switzerland.

Atmos watch by Jaeger- LeCoultre, Switzerland.
Gilded metal and glass case. Porcelain enameled dial.
Signed and numbered S0001.
Enclosed guarantee book and original box with complements for its use.
In running condition.
Measurements: 22.5 x 19 x 15 cm. (clock), 24 x 21 x 17 cm. (box).
The Atmos table clock, from the Swiss firm Jaeger-LeCoultre, is a luxury piece of extraordinary precision and quality. Its open structure invites to study its mechanism to understand its secret. Made of bronze, it has a round white dial with bronze profile, with sword-type hands and applied numerals, with Arabic numerals at 3, 6, 9 and 12 o'clock. The particularity of this watch is that it works by taking energy from changes in ambient temperature and atmospheric pressure, so that it can run for years without human intervention. Its energy source is a hermetically sealed capsule containing a mixture of chloroethane gas and liquid, which expands in an expansion chamber when the temperature rises, compressing a coiled spring. When the temperature drops, the gas condenses and the spring decompresses. This constant motion coils the mainspring. A single degree of temperature variation (in the range of 15 to 30°C) or a pressure variation of 3 mm Hg is enough to keep the watch operational for two days. The little added energy needed for its operation requires the mechanism to work with the least possible amount of friction, hence a torsion pendulum is used as a regulating mechanism, which consumes less energy than the ordinary pendulum, since it oscillates only twice a minute (1/60th the number of oscillations of a conventional pendulum clock). The first clock powered by changes in temperature and atmospheric pressure was invented by Cornelis Drebbel in the early 17th century, and his experiments were continued during the Enlightenment by Pierre de Rivaz and the watchmaking couple James Cox and John Joseph Merlin. The oldest clock of this type still in operation is the Beverly Clock, built in 1864. In 1928 the Swiss engineer Jean-Léon Reuter created the first Atmos clock, a non-commercial prototype that still lacked the mercury expansion glass. In 1929 the French firm CGR produced the first commercial model, and in 1935 Jaeger-LeCoultre produced the Atmos 1, while developing the current chloroethane-based system (Atmos 2, 1936).