Galvanometers can also be used to measure temperature because, as noted above, an electric current is formed when metals are heated. The current thus produced is proportional to the temperature to which the metal is heated. Consequently, a galvanometer reading in current indirectly measures the temperature.
Galvanometers are used for the measurement of lower temperatures up to 1100° F. They are hung vertically, and the scale and finger are made very bold, so as to enable the operator or workman to recognize the temperature at a glance, without having to go close to the instrument.
When used for scientific and other work requiring exactness and precision, galvanometers constructed to register up to 1100° F. can be used only in a horizontal position on a table or in a bracket. This limited use is also common to galvanometers constructed to register higher temperatures up to 2900° C, and to those designed to register very low temperatures.