LeCoultre Atmospheric Perpetual Clock

For centuries, many scientists—including Leonardo da Vinci—had experimented with the idea of a Perpetual Motion mechanical devise. The energy to power such a devise is all around us, light from the Sun, gravity, water currents in streams, rivers and oceans. But utilizing that power has proven to be elusive, albeit a fascinating and tantalizing problem. In fact, watchmakers and clockmakers have struggled to overcome the problems caused by these natural atmospheric occurrences.

In the late 1920s Jean-Leon Reutter, a young Paris engineer, experimented with a clock that needed no direct mechanical or electrical intervention to keep it wound; in short a clock powered only by perpetual motion. His idea was to utilize barometric pressure, changes in temperature and humidity.

Through out his life, J.L. Reutter dreamed of a perpetual motion timepiece. This led him to produce a clock with a timekeeping mechanism designed to consume the smallest possible amount of power to keep the clock running satisfactorily.

Reutter studied the design of the 400-Day Anniversary Clock. He then made changes to the escapement, to meet the miniscule power requirement he was looking for in his new clock design. Reutter’s modified the escapement leverage to reduce the arc of the escapement, as well as adding jewels to the bearings of the movement. This time-consuming endeavor proved very successful, and his new clock not only ran, but was extremely accurate.

His new clock design would be powered by an atmospheric barometric bellows. He utilized mercury in a glass tube, similar to that of a thermometer, and encased it all inside a metal cylinder

Reutter’s ingenious new clock was unlike any other, past or present; a timepiece that could run independently and continuously, rewound by the slightest fluctuations in the atmosphere or temperature.

Mercury is inherently dangerous and unstable, and was later replaced with a more stable saturated gas, Ethyl Chloride. The bellows in an Atmos contains a mixture of gas and liquid, which expands as the temperature rises and contracts as it falls, moving the drum face back and forth like an accordion. This motion constantly winds the mainspring, as you would wind your watch, keeping the mainspring constantly wound. A small temperature change of just one degree will wind the clock is sufficient for two day’s timekeeping. Such a temperature variation occurs naturally, so the Atmos clock will continue to run and keep time “perpetually.”

Reutter’s Perpetual Motion Clock was in its initial production during the early 1930’s, but only in small quantities. The lack of enthusiasm from manufactures made production of his clock difficult.

While Reutter was struggling with production of his Atmospheric clock, the manager of LeCoultre was strolling down a street in Paris one day and noticed one of Reutter’s Atmos clocks in a shop window for sale. He was so fascinated with the clock, he walked in and purchased it. Soon after Reutter was contacted by LeCoultre, and he sold his license and, eventually, his patent to the Atmos clock to the LeCoultre Watch Company.

LeCoultre was in fierce competition with another watch company, Ed Jaeger of Paris. Eventually LeCoultre merged with Jaeger to form Jaeger-LeCoultre.

Jaeger & LeCoultre poured considerable investments, collective research and development into Reutter’s Atmos clock. Soon after major production of the newly revamped Atmos clock was launched under the Jaeger-LeCoultre name exclusively. No other watch or clock company produces anything like this very unique “perpetual motion” clock.

The LeCoultre Atmos clock soon became a very fashionable, prestigious gift in Switzerland and, eventually, worldwide. By 1979, Jaeger-LeCoultre had produced 500,000 Atmos clocks.

  • Chris

    What’s the secret to keeping it running?

    • steve

      if you’ve ever seen a barometer you’ll notice that it has moving parts. these work with air pressure. now this clock works by harnessing the power of a barometer in order to wind the spring rather then turn a dial displaying the weather

  • My “LeCoultre Atmospheric Perpetual Clock” was stolen from my house last week. It was in perfect condition in all ways. It looked like the day it was made and it was handed down to me back in the very early 70’s. It has remained as a center piece on my mantel till now. What is it worth at this time? The police want to know worth because they caught the person but no clock. They were caught on 5 video cameras stealing much from my house. Please help me. Thank you. Can I get another one anywhere?

  • Dan Goodson

    I have one and I had it repaired, wife moved without locking down, about 20 or more years ago and they told me it was worth at least $1,500.00. Remember this was at least twenty years ago (I won it in a sales contest in 1978) years ago. The jewelry store was Brown’s jewelry in Charlottesville, Virginia. You might wont to call them. Sorry do not have their number currently.

    Mine is still running good.

    Dan Goodson

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