John Carmichael wrote: >You couldn't use pure water in the sun to float a mirror because algae would >soon grow in the water. I don't know what kind of clear liquid is used in >my Silva compass that uses this liquid to dampen the needle. Perhaps there's >a little alcohol added to keep it sterile.
Arising from this, I have a WW1 military prismatic marching compass with a beautiful mother-of-pearl card which has lost some of its 'spirit' and so no longer floats level. Can anyone tell me what these instruments were originally filled with please as I'd like to replenish it? Best Wishes Tony Moss
