The Serial Number of an Atmos Clock is usually located on the top of the Movement, by the Speed Adjustment Lever. On some very older models, the serial number may actually be on the front of the Movement -near the hands and on Antique Reutter Clocks the serial number is often on the Back Drum portion.

What winds the Atmos clock up?

When the temperature falls, the gas contracts, which in turn reduces the size of the capsule. Each time the capsule changes, it activates a small chain, which winds the clock.