ATMOS CLOCK WITH GLASS DOME by Atmos Pendule Perpetuelle 6382 Ca. 1932-1835 France
ATMOS CLOCK WITH GLASS DOME
Signed: Atmos Pendule Perpetuelle 6382
The spring-driven movement of this beautiful Atmos clock has a going train only. It has a large chrome-plated brass balance with torsion wire suspension, visible below the movement. The movement is wound by a temperature-sensitive mechanism. Should the temperature remain stable, the clock will continue to run for 90 days. The drum is secured by a bar with the punched number 6382 and a plaquette with BREVETS J.L. REUTTER S.G.D.G.
The circular silvered skeleton dial has a Arabic chapter ring with five-minute and minute divisions. The maker has signed the dial ATMOS PENDULE PERPÉTUELLE. The time is indicated by a fine pair of steel hands. In the center the movement is numbered 5208 and on a small disc behind the movement is the text ATMOS, France, unadjusted fourteen jewels engraved.
This Atmos clock by J.L. Reutter is fixed on a black stone basement with a chrome-plated brass strip. The balance can be secured by a slide under the basement for transport purposes. The clock is protected by a glass dome.
Duration Infinite, in case of no temperature differences 90 days.
Height 27,5 cm
Width 34 cm
Depth 16 cm
*Price on request
– J. Zeeman, Het Klokkenlexicon, Zwolle, 2003, p. 17
– Jean Lebet, Von der Luft leben: die Geschichte der Pendeluhr Atmos, Jaeger-LeCoultre, 1997.
Jean-Léon Reutter (Neuchâtel, Switzerland, 1899-1971) is the inventor of Atmos clocks. In 1913 this engineer, based in Paris, started his experiments which would eventually result in the production of the Atmos clock. He actually developed ideas of James Cox who thought of a self-winding system as early as 1765. In 1926 the first commercially produced clock was introduced on the market. He applied for the first patent in 1929. Reutter made used of a U-shaped glass vessel, which is positioned in such a way that small deflections were possible which wound the main spring continually.
Note on the working
The horizontal arm of the U and part of the vertical tubes are filled with mercury. In the vacuum above the mercury is a fast evaporating liquid and saturated vapour. One of the vertical parts is insulated, whereas the other is not. When the temperature rises more in one leg than the other (because of the insulation) a small amount of mercury is moved, causing the U to slightly change shape, which is used to wind the main spring. A temperature fall has the same effect. Later models use an aneroid metal box which works like a barometer and causes mechanical displacements winding the main spring.