There has to be no other clock in the world as singularly unique as the Atmos from Jaeger-LeCoultre. Most of the time when we encounter one, it sits there, giving us the time; betraying no clue as to the groundbreaking idea that it holds — so that when we examine the clock more closely and are told the concept behind how it works, we consider what we have just heard scarcely believable. Indeed, it is an idea that is both simple and profound at the same time, and we are compelled to believe that it is true, for the object exists, and works quietly, in front of you.
It is the intersection of invisible elements in the Atmos that so beguiles us; that easily understood concepts like temperature and pressure could be linked together in such a startling way to produce a machine that runs forever.
How does the clock work? Simple.
The key is a capsule filled with ethyl chloride gas, notable for its property of responding to changes in temperature with relatively large changes in volume. This is what enables the expansion and contraction of the capsule, a motion whose energy is transferred to a chain that moves back and forth, winding the mainspring in the process.
From here on, the power gathered by the mainspring is used to run the clock movement — one made as finely and as precisely as humanly possible to minimize friction and loss of power. In fact, the clock is so efficient that only a one-degree change of temperature is enough to run it for two whole days.