December 20, 2023 Atmos Clock!
Wow! Bill got me something I’ve wanted for literally decades, about 4 of them - a Jaeger-LeCoultre Atmos Clock!!! It’s an older model that Christopher had restored perfectly. Weirdly enough, these clocks don’t really hold their value, so it was quite affordable. Unlike most torsion wire clocks, this one’s pendulum lock actually works, so it wasn’t even difficult to transport.
The most amazing thing about an Atmos clock is that it does not need winding! You read that correctly, you never need to wind one of these!
How can that be?? Well, that big drum at the rear contains a bellows that expands and contracts as the temperature changes slightly, that motion winds the main spring! Here’s the details https://www.jaeger-lecoultre.com/us-en/jaeger-lecoultre-atmos-history. There have even been scientific papers published about the Atmos clock https://tigerprints.clemson.edu/cgi/viewcontent.cgi?article=1007&context=mecheng_pubs.
Martin, being unscripted didn’t quite get it right. That was just a half beat in the video. The full beat of a pendulum clock is defined to be the motion from a point until it returns to that same point. In this amazing clock, the period is one full minute!
The period of a torsional pendulum can be found using:
The units for the torsion constant are [k] = N • m = (kg • m/s2)m = kg • m2/s2 and the units for the moment of inertial are [I] = kg • m2, which show that the unit for the period is the second.
The only identification number that Martin has been able to find is on the bottom of the clock. The lever you can see that goes from the center to the front of the clock, is the pendulum locking lever, used to transport the clock safely.
Ah ha! There’s the serial number 229750, just had to get the right light to see that it is on the right side of the fast-slow adjustment. From this page we can see these serial numbers:
Bellows Date Serial #
12/8/1966 232685
229750
10/25/1966 226097
So we know that this clock was manufactured in November of 1966 so it is about 57 years old now. That page also shows it to have a caliber 528-8/6 movement.