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Jaeger leCoultre ATMOS Clocks

by Jason 25 April, 2011 View Comments

JLC Atmos

One of the most elusive and often-hoaxed technologies is the grail of perpetual motion. Many a crackpot has devoted their life to discovering the secret of unlimited energy and motion. What a lot of people don’t realize is that something very close to perpetual motion exists – and it is in the Swiss clock world. And it has existed since 1928.

JLC Atmos Front

The Jaeger leCoultre Atmos is a clock that uses temperature change to power the movement, allowing it to run indefinitely without any need for winding. It has its roots in a 1928 design by a fellow named Jean Leon Reutter. He was not the first to build an “atmospheric” clock driven by barometric pressure or temperature changes; such designs had existed since the 1600s and had been built in very small numbers over the centuries. Reutter’s design was more compact, more efficient, and was one of the first to be mass-produced in large numbers, first by the French firm Compagnie Generale de Radio in 1929 and then by Jaeger leCoultre from 1936 onward.

Atmos Diagram

The Atmos is one of the most fascinating mechanical devices available to the public - the only thing cooler might be a homebuilt nuclear fission reactor, but the Atmos is a lot safer and comes with a warranty. It uses a simple principle that is very complex in execution – the natural fluctuation of temperature in the atmosphere is harnessed as a way of producing energy to wind the spring of the movement. As long as the temperature changes by at least a degree, the Atmos will keep running. In fact Jaeger leCoultre claims that one degree of variation is enough to provide two days of power - efficiency is the real marvel of the Atmos design.

JLC Atmos Rhodium

The movement is driven by a spring that is moved by a bellows chamber filled with gas. When the temperature rises, the gas expands, and the spring is compressed. The reverse happens when it cools. The back and forth motion of the chamber spring is transferred to the mainspring of the clock which powers the gears. But all of this would be useless if the whole clock was not designed to consume only a tiny amount of energy.JLC Atmos Movement

In a normal mechanical movement, you can expect the balance (the heart of the movement) to beat back and forth several thousand times per hour. Even the most leisurely watch movements run at 18 000 beats per hour; some run 36 000 bph or more. This motion consumes a lot of energy to drive the various gears needed to tell the time. The Atmos beats at a near-comatose 120 bph. The pendulum (a rotating weight at the bottom of the clock) swings slowly back and forth every 30 seconds.

A slow beat is only part of the solution. There needs to be an absolute minimum amount of friction in the whole movement. Everything is simplified and stripped to the bare essentials. It uses no oil or lubrication. One of the most amazing things is the claimed service interval – because there is so little friction JLC claims that, in theory and without any dust or pollution in the air, the clock can run for 600 years without service. They do suggest more “frequent” adjustment, around every 20-30 years. Compared to the usual 3-5 year service intervals of a mechanical watch, going decades without service is downright miraculous.

All of the technical doohickery aside, the Atmos is a beautiful clock. Even the “classique” models like the two we have here are beautifully finished and skeletal in design. Everything is open and visible through the glass case; even at first glance you know this is not your run-of-the-mill mantle clock. JLC has made decorated and more complicated models of the Atmos (for a lot more money), but these examples have a stunning mechanical beauty even without the extra decoration. It’s a great piece for mechanically obsessed folks like myself. It’s fascinating to watch the movement function, if a bit slow – the parts move at a glacial pace, so don’t expect any mechanical fireworks going on in there. On the plus side, it is completely silent, so if a tick-tocking mantle clock keeps you up at night the Atmos is a perfect solution.

JLC Atmos RegulatorBoth models here are of the same design but with different finishes. Both are made of solid brass; the silver tone is rhodium plated to look like white gold, while the goldtone is – surprise – gold plated. The gold tone features a classic Roman numeral dial while the silver tone has an Arabic numeral design that is more modern. Both have a solid weight to them and built-in adjustable feet to keep them level. JLC puts a small levelling bubble on the base to make setup easy, a handy feature that should be on all clocks.

I’ve always been fascinated by the Atmos. It sounds like impossibility - a clock that never needs winding, the closest humanity has come to creating a perpetual motion machine. And you can buy one and stick it on your mantle! That sort of technical feat is enough to make any gear-head swoon, and if you love fine watches these clocks are just the ticket. Jaeger le Coultre has made a name for themselves by building superb watches and clocks throughout the 20th century, and these Atmos clocks are a worthy heir to the JLC legacy and the perfect accessory for a watch lover’s home. Both our Atmos clocks are new-in-box, if you are interested in either please feel free to give me a call at 514 845 8878 or visit our contact page.


Jason Cormier

Atmos Pendulum

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