(edited) dates from around 1960. An Atmos Perpetual Clock by Jaeger LeCoultre of Switzerland. It is powered by variations in air temperature and pressure and never needs winding. It's made of gold plated brass. The clocks are hand made and each one takes around 1 month from start to finish. New they cost between $3000 and $5000 (for this model and up to $40,000 for the top-of-the-line) so I would never own one if it weren't for the second hand market.
wouldn't that mean it would be inaccurate in the mountains were the air is thicker???????????It is powered by variations in air temperature and pressure and never needs winding.