Since we're talking about things electrical, I wonder what the opinion
is on open mercury switches. My orchestrion has two vials which, I
assume, contained mercury. When the coin drops, a metal wire falls into
the vials, completing the circuit. This switch is not enclosed. I have
a european wall box that works the same way. One fellow told me that
mercury evaporates, creating a poisonous gas around the piano! Is it
best to use a micro-switch?  Philip Jamison