A French Art Deco nickel plated Reutter Atmos clock, circa 1930
Reutter patent Atmos
In 1927 Jean-Léon Reutter created his first prototype clock which driving spring is wound by changes in temperature and barometric pressure. After a number of adaptions and improvements a commercial production line of the Reutter patent Atmos was started up in the middle of 1929. There were a number of inventions that made this technical marvel possible. He used a torsion pendulum, known from 400-day clocks, and by enlarging it ensuring a very low ticking count. He made the suspension wire from elivar, an alloy insusceptible to temperature changes, which improved the precision very much. The movement was finely made and executed with ruby end stones causing it to need very little energy. In fact, the clock only needs 1/1000 of the energy that a conventional movement needs. These improvements were combined with his winding mechanism. This consists of a drum which can turn between two blocking pins. In the drum there is a U-shaped glass tube filled with mercury and ammonia gas of which one part is insulated. By changes in temperature and barometric pressure the ammonia gas expands or retracts in comparison to the gas in the insulated half. This causes the mercury to shift which motion turns the drum. This turning winds a spring which drives the mechanism.
Between 1930 and 1938 these clocks were produced under the direction of Reutter. After this period Jaeger leCoultre took over the patent and modified the winding mechanism. The production of the modified Jaeger LeCoultre version commenced after the Second World War. Because of these developments, the number of Reutter patent clocks remained limited. These Reutter clocks were executed with different cases. These nickel plated Art Deco versions are fairly rare because they were too modern for the large public. Nowadays these clocks are wanted because they fit in any interior and have a timeless quality.
The dial has applied Arabic numerals and is signed Atmos below number 12. The blued steel hands are of the Breguet type. The dial is fitted in a nickel bezel.
The movement is driven by a spring. This spring is wound by a mechanism which functions on changes in temperature and barometric pressure. It causes a drum to turn. This turning motion winds the spring. The exceptional movement requires very little energy to run. With only one degree Centigrade temperature difference, the clock can run for 48 hours. The clock is regulated by a large horizontal balance wheel with adjusting screws which has a thirty second oscillation time. Since there are always changes of temperature during the course of the day, the clock is wound continually and will run continually. That is why Reutter called ‘Pendule perpetuelle’ (perpetual clock). The bracket with which the movement is fixed in the case is numbered 4350 and has a plaque inscribed ‘BREVETS J.L. REUTTER S.G.D.G. MADE IN FRANCE.
The nickel plated case has glass panels to all sides including the top which makes the movement visible. The straight lines and canted base are typical for the designs of the Art Deco period, the unadorned but balanced style of the 1920’s and 1930’s.