Share |

Home Site Stats Advertise Contribute Add Link About Us Help/FAQ Contact Us Forum


Find Clocks By Keyword


Atmos Clocks

The "Atmos" brand clock is an ingenius contraption that comes closest yet to being a "perpetual motion" machine. It is a mechanical clock Produced by the Swiss firm of Jaeger-LeCoultre, it is a mechanical clock that runs without needing anyone to wind it up periodically. It runs on the energy produced by natural changes in temperature and barometric pressure in its environment. Left undisturbed it can run accurately for years without the need for winding from the outside. You'll never lose a winding key with this clock - it doesn't have one!

It's powered by the natural expansion and contraction of a mixture of gas and liquid ethyl chloirde contained in a sealed capsule. When the clock's surrounding temperature rises the gas expands into an expansion chamber which causes a spiral spring to be compressed. When the temperature falls the gas condenses, relieving pressure against the spring. This constant expansion and contraction of the spring keeps the mainspring wound, eliminating the need for human intervention. A one degree change in temperature between 59 and 86 degrees Fahrenheit (15 to 30 degrees Celcius) is enough to power the clock for two days. A change in the atmosphere's barometric pressure of 3mmHg or more produces the same effect.

Friction is the enemy of perpetual motion. In order to keep the friction of the operating movement to the least amount possible the Atmos clock uses a torsion pendulumIn order to run the clock on this small amount of energy, everything inside the Atmos has to work in as friction-free a manner as possible. For timekeeping it uses a torsion pendulum, a delicate device that functions using far less energy than the more odinary pendulum that swings in a left-right-left-right motion. A torsion pendulum is a weighted disk or wheel which hangs by a thin wire (called a torsion spring) attached to the center of the disk. If you were to look straight down on the disk from above, you would see the disk rotating in a clockwise/counterclockwise motion instead of the swinging motion of an ordinary pendulum. The rotation twists the suspension spring first one way, then the other twisting it, instead of swinging like an ordinary pendulum, releasing energy as it unwinds in each direction. The torsion pendulum of the Atmos clock makes only two oscillations per minute, keeping friction to a minimum. A conventional pendulum swings at 60 times that rate.

Atmos Development Timeline


A prototype of the first Atmos clock was produced by Jean-Léon Reutter, a Swiss engineer. It used encapsulated mercury as the expansion/contraction mechanism and relied solely on the changes of temperature to run the clock. This prototype was not used for commercial production and it predated the Atmos brand name, but it has become unofficially named the "Atmos O" model.

June 1, 1929.

A french firm, Compagnie Générale de Radio (CGR), began production of the first commercially sold Atmos model, the "Atmos 1". It used a chamber filled with mercury and ammonia as its power source.

July 27, 1935

The Swiss firm Jaeger-LeCoultre took over manufacture of Atmos 1.

January 15, 1936,

Jaeger-LeCoultre announced the next generation of Atmos clocks, the Atmos 2 model. It used the same gas and liquid ethyl chloride mixture found in Atmos clocks still currently made. Problems delayed the full production of the Atmos 2 until mid 1939. A long list of subsequent models are all based on this design. To date, Jaeger-LeCoultre has sold more than 500,000 Atmos clocks.

See all Atmos clocks listed in the Antique Clocks Identification and Price Guide

Find out what dealers and collectors have actually paid for antique grandfather, mantel or wall clocks like yours. Covers American, European and Continental clocks of all types.

We have 38,769 antique clock prices, images and descriptions as of March 1, 2024.


Learning More About Antique Clock Types

Signup Now

Have an account?
item14 item11 item10