Description

ELEGANT METALLIC THERMOMETER, French, c. first half 19th century. The large wall-mounting wood support is 9-5/8″ x 10″ x 5/8″ (24 x 25 x 1.6 cm) with a fine mahogany veneer and set with a Centigrade (Celsius) degree scale running from “Glace” at 0° up to 33° (equivalent to 91° Fahrenheit), the brass scale divided every degree. A short support arm has two little concave wells, the arm¹s tilt adjustable from behind. And there are two wall mounting lugs. The thermometer itself has two adjustable pins that sit in the wells and lead to a long index pointer, and to a side arm supporting the metal half-round which expands and contracts with the temperature. The end bears a ball weight, its position adjustable for calibration. The central area of the metal arc is filled with a thin wood panel. Condition is fine noting small cracks to this panel.

This professionally made instrument is the only one of its kind we have seen. Middleton (1966, A History of the Thermometer) discusses various “Deformation thermometers,” primarily bimetallic.