Rutherford maximum and minimum thermometer, 1794

Rutherford type maximum and minimum thermometer, by Lake & Son, Taunton, Somerset, England, 1794

The aspect that made the Rutherford maximum and minimum thermometer innovative was the way the temperatures reached were marked by a tiny steel spring inside the tube. This would be pushed up by the mercury or down by the spirit, and lodge at the extreme positions of the readings. This example was made by Lake of Taunton.