Home Continuing Series Historical Horology Historical Horology: The Jaeger-LeCoultre Atmos Clock

Historical Horology: The Jaeger-LeCoultre Atmos Clock




Perpetual motion. That’s been the dream, the myth, that so many have chased after in the past. Sure, we might think that we’ve gotten close with our automatic mechanical watches. While those certainly are an engineering marvel in their own right, they still rely on our input to store energy – and they will, at some point, require maintenance of their various small bits and pieces.

But, what if there were something that could keep running without any visible energy input (no winding, no cords), as well as maintain accuracy with some minimal maintenance? As you’re likely guessing from the title of this post, this is some JLC actually accomplished – back in the 1920s.


So, how does the Atmos keep itself running? It utilizes something that’s constantly changing – the temperature of the air. And it’s not like it needs the wild differentials, either. By relying on materials that are extremely sensitive to minor changes in the temperature (the modern Atmos utilizes a bellows filled with ethyl chloride), the clock can keep running so long as the temperature fluctuates one to two degrees Fahrenheit.

That’s only one part of the equation, of course. To keep things running as long as possible, friction and resistance has to be eliminated or reduced as much as possible. Additionally, the pendulum of the clock only beats twice per minute, further enhancing the longevity of the timepiece.


These clocks are rather quite interesting – and they’re not gimmicks, either. The Swiss hold them in such high regard that they’re given to visiting foreign dignitaries (such as Winston Churchill, JFK, and Ronald Reagan) – a mark of high honor, for both the gift and the recipient.

I find the unique methods utilized by this sort of clock completely engrossing, and point to them as a sign of what clever clock (and watch) makers can do when they set their minds to thinking outside of the normal conventions present in the industry, and across the decades. Of course, my writing here only scratches the surface of what there is to learn. If you’d like a more in-depth look at the history of this type of clock, check out this excellent article over at Gear Patrol.



Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.