Atmos – the virtual PERPETUAL MOTION clock

A look into the fascinating device that is the Atmos Clock

Some of the most important developments in the evolution of manufacturing and industrial production resulted from a fascination with measuring passage of time.  Once it was realized there was a pattern to daylight hours sundials were developed to measure and project time.  To extend into the hours of darkness one solution was the clypsedra (water clock) using the transfer of liquid either into or out of a container at a controlled flow rate. Another employed insense burned at a measurable rate to yield results satisfactory for the measured period.  Gallileo is credited with developing the pendulum to further refine timekeeping (though he did not actually build the first pendulum clock; his drawings exist). Applying the pendulum to regulate energy from falling weights was done by a Dutchman, Christian Huygaans).  Later, springs were incorporated to power clocks, and to enable navigators to tell time on shipboard where a pendulum would not function, John Harrison invented the hairspring, which led to smaller clocks and ultimately to wrist (and even ring) watches.  As accuracy demanded, timepieces were developed to operate with electricity then quartz and computer chips.  
Concurrently, man’s fascination with the prospect of perpetual motion – a device that virtually consumes no more energy than it produces – attracted horologists (clockmakers).  Several examples of perpetual motion clocks were produced and at least two – the Cox clock made in 1763 and currently displayed in London’s Victoria and Albert museum and the Beverly clock, a timekeeping experiment from 1860 displayed in the Science building at Octago University in New Zealand are currently still operational.

The only known “perpetual motion” clock actually manufactured and sold on a large scale is called the Atmos.  Invented in France in 1928 by John Leon Reutter, the Atmos incorporated a “motor” comprised of two glass bulbs and a small interconnecting tube charged with mercury and anhydrous ammonia.  Changes in temperature caused shifting of the liquid from one bulb to the other.  The glass container, balanced on a pivot rocks back and forth, pulls a chain that turns a ratcheted cam wheel and winds the clock’s mainspring.

Mr. Reutter ultimately turned to watchmaker LeCoultre in Switzerland to enhance distribution of the Atmos, and after some modifications the LeCoultre Atmos began its life in about 1936.  One significant change was a re-design of the motor to replace the very fragile glass bulb assembly, and eliminate the potential hazard of shipping clocks around the world with the charge of mercury. The new design, using a metal bellows containing ethyl chloride gas that is very susceptible to changes in temperature and atmospheric pressure remains essentially unchanged through models of the Atmos still sold. 

LeCoultre literature describing ” The clock that runs on air” points out that a two degree temperature change will wind the Atmos for 48 hours. There is no practical means for the owner to wind it.  It is assembled with a full wind on the mainspring which is then maintained by the operation of the automatic winding mechanism. The design incorporates safety to prevent over-winding, but as the clock is always operating fully wound it provides very reliable timekeeping.  

Much more to follow, including inside looks at the Atmos and maintenance, operating and service information directed at owners and clock repairers.

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