Imagine a device you use every day, whether that’s a remote control, an electric toothbrush, or your smartphone.
Now imagine you never had to change or charge up the batteries. How freeing would that be?
Our toothbrushes would never fizzle out, our smartphones would never hit 0%, and that beeping from the smoke detector would stop forever.

In the watch world, we think of watches without batteries simply as automatics. They wind by movement from your wrist and arm throughout the day. The Atmos clock, however, doesn’t need movement from a human and surely doesn’t require a battery.
Additionally, is not powered by a suspended weight, like a pendulum clock.
The Atmos, produced by Jaeger-LeCoultre with a history dating back to 1928, is run by temperature and atmospheric pressure changes in the environment.

In fact, a single change in degree (between 59 and 86 Fahrenheit) or pressure variation of 3 mmHg can power the clock for two days. The clock’s balance swings just twice per minute, conserving energy.
And because the entire machine runs on little energy, everything must work free of friction.
Clocks running on atmospheric pressure changes isn’t a new idea — in fact, that technology dates back to the 17th century.

The clock works by having an ethylene chloride gas-filled capsule in its interior. When the temperature rises or falls, the capsule expands or contracts.
The capsule’s wall is connected to a chain, which moves in a back-and-forth motion, winding the mainspring.
This clock, despite being an engineering marvel with quite its own history, can be found affordably. However, more expensive and elaborate models can run north of $200,000.
Mark Sirianni Watch Repair
25 Fraley Street
Kane, Pa. 16735
814-837-9435
814-558-4818 (cell)
watchdoctorpa@gmail.com

13 Comments
Bissell Patrick
Wow! Really interesting lesson. Thanks Nark
Mike Graves
Wow! Beautiful! Both in concept and design!
John Heagerty
Cool. Hey, Mark, do you ever work on Atmos clocks?
Franz Fleischli
WOW! is my reply as well. Impressive on all conceivable levels.
Juha Airio
Beautiful piece of art ! Thanks Mark !
Johnny
Had no idea a clock was invented to run on temperature and atmospheric pressure.
Antonio Palermo
Truly brilliant! Thank you for explaining it in great detail Mark.
Greg Millard
I have one my Dad bought in 1956 and it has been operating very accurately since – the greatest hazard to their health is movement (eg ‘helpful’ cleaners) without locking down the mechanism. Oh, & don’t expect a tic-toc, or any noise as they are perfectly silent
Todd Dean
That is just another fascinating, well written article by the Watch Doctor.
Clint Edwards
I have one and it ran well for about 11 years after it’s last repair. It no longer runs, and the man who serviced and repaired it just retired. So it is now just a display piece.
Super cool when it was running.
Justin
When I was little my family would stop at Cakfwell’s in Philadelphia (next door to Wanamakers) and my dad would explain how the Atmos clocks worked. It was like magic!
Justin
Oops! Caldwell’s
Sarah Smith
It’s fascinating that clocks can run automatically off atmospheric pressure changes! The pictures in your article remind me of the clock I’ve seen on my mom’s piano. However, hers has stopped working. Since it doesn’t run off batteries, should I find a clock repair specialist who understands the workings of an Atmos clock?