I wonder why Chloroethane / ethyl chloride was chosen. I don't think I've ever seen this for anything, other than a synthesis precursor to useful stuff.
My guess: it is a relatively safe compound with the right properties to act as a working fluid for this movement. The text linked below mentions the working fluid and the property that the vapor pressure is highly variable over the range of normal room temperatures.
My guess: it is a relatively safe compound with the right properties to act as a working fluid for this movement. The text linked below mentions the working fluid and the property that the vapor pressure is highly variable over the range of normal room temperatures.
Here is a document with details and history about these clocks: https://www.physics.rutgers.edu/~matilsky/documents/Atmos/At...