An Experimental Determination of the Change in Temperature Accompanying Change in Magnetization of Iron

Apparatus.—An apparatus is described which permits the measurement of the change in temperature of a ferromagnetic material consequent upon a change in its magnetization. The test specimen, of peculiar form and construction, is placed in a specially designed calorimeter. Around this is wound a solenoid which furnished the magnetizing field. Changes in temperature are measured by means of 102 thermocouples connected in series to a sensitive galvanometer. Methods are described for minimizing thermal and thermoelectric disturbances. The sensitivity of the system is such that a temperature change of 2.26×${10}^{-6\mathrm{}}$°C can be detected. This corresponds to a thermal energy change of 87 ergs per ${\mathrm{cm}}^3$ for steel.