With the Atmos, the drive energy is generated by fluctuations in temperature and air pressure.
A large pressurized can (at the back) is filled with chloroethane. A spring mechanism opens its expansion (switching). A temperature change of 1 degree is sufficient for 48 hours of operation. The torsion pendulum oscillates for 1 minute. The manufacturer is Jaeger-LeCoultre (Le Sentier, Switzerland). The watch was invented by the Swiss engineer Jean-Léon Reutter around 1928.