Phys., 1895, 6, p. 296) heats three parts of the oxide with one part of magnesium powder.
He also showed that the difference of the specific heats at constant pressure and volume, S - s, must be the same for equal volumes of all gases at the same temperature and pressure, being represented by the expression R/TF'(t).
He remarks that ” the law according to which the motive power of heat varies at different points of the thermometric scale is intimately connected with that of the variations of the specific heats of gases at different temperatures - a law which experiment has not yet made known to us with sufficient exactness."
If he had ventured to assume the difference of the specific heats constant, it would have followed that F'(t) must vary inversely as T.
In the course of his inquiries he also noticed that different bodies in equal masses require different amounts of heat to raise them to the same temperature, and so founded the doctrine of specific heats; he also showed that equal additions or abstractions of heat produced equal variations of bulk in the liquid of his thermometers.