Critical Discussion of the Conception of Temperature

Abstract

It appears from what has preceded that the volume of a body may be employed as a mark or index of its thermal state, and that consequently change of volume may be looked upon as indicating a change of thermal state. It is understood that the changes of volume here involved are not such as are determined by alterations of pressure or electric force, or by any other circumstances inducing change of volume known from experience to be independent of the thermal state. Concomitantly with the heat sensation which a body provokes in us, other properties of the body also undergo alteration — as, for example, its electric resistance, its dielectric constant, its thermoelectric motive force, its index of refraction, and so on. And not only might these properties be employed as indicators of the thermal state, but they actually have occasionally been so used. In preference for volume, as a measure of states of heat, therefore, there is involved, despite the manifest practical advantages of the choice, a certain arbitrariness; and in the general adoption of this choice, a convention.