Jaeger LeCoultre 1950s Atmos Clock

A fine example of the classic ‘Atmos Clock’ by Jaeger LeCoultre in a gloss gilt case with rare black dial. Invented in 1928 by Jean-Léon Reutter, the ‘Atmos’ clock was designed to run almost perpetually, driven by a mainspring which is wound by changes in temperature and atmospheric pressure. In 1935, Jaeger LeCoultre took over production of the Atmos clock, developing a second, more reliable design – Atmos II. Contained in an airtight chamber, a liquid and gaseous ethyl chloride expands and contracts with changes in temperature, compressing and releasing a spring, which in turn slowly winds the mainspring. A 1 degree change in temperature is enough to run an Atmos clock for 4 days! The timekeeping is controlled by a torsion pendulum, suspended on a thin wire and ‘twisted’ one direction and then the other with power from the mainspring, moving much slower than a typical pendulum clock, and consuming far less energy. Being self powered, the clock can run completely independently, requiring virtually no human intervention, besides the occasional servicing or timekeeping adjustment. Non-striking, this design also means that the movement runs silently, no ticking! This clock would be an Atmos III, the movement stamped with serial number 48430, meaning it would’ve been manufactured somewhere between 1950 and 1959, most likely around 1954. The case is gloss gilt brass, in two parts, the removable top cover, with all glass panels in excellent condition, sitting securely on the stylish brass base. The base is supported by three hidden feet, which can be adjusted from within the case, centering the bubble of the spirit level built into the base plate to ensure perfect balance, and efficiency of the movement. Within the glass panels can be seen the black chapter ring, with Arabic numerals at 3, 6, 9, and 12, and faceted gilt batons between, as well as the fine Atmos movement, all in brilliant condition, with the suspended pendulum turning slowly below. To secure the pendulum during transport, there is a lever underneath the base, which, at the very end of a pendulum turn, just before it begins to spin the other way, can be moved all the way to the right to secure it in place, making it possible to move the clock without damaging the wire upon which the pendulum hangs. This clock has been recently overhauled and is sold with a 24 month gurantee.