This mercury-in-glass thermometer can be accurately dated to 1774-1793 because its English makers, Nairne and Blunt, were only in partnership for that period. It is marked in degrees Fahrenheit, a system in which water freezes at 32 degrees and boils at 212 degrees. Mercury was used in thermometers because it is a liquid over a wide temperature range and expands in volume ten times more than glass. Long-term temperature records have helped meteorologists and mathematicians understand and model o...
Thermometer, Fahrenheit, with case, glass / mercury / metal / wood / shagreen, Nairne and Blunt, London, England, 1774-1793