Note 59 — ON THE PRINCIPLE OF THE CONSERVATION OF ENERGY.[39]

A better terminology appears highly desirable in the place of the usual misleading one. Sir William Thomson (1852) appears to have felt this need, and it has been clearly expressed by F. Wald (1889). We should call the work which corresponds to a vanished quantity of heat its mechanical substitution-value; while that work which can be actually performed in the passage of a thermal condition A to a condition B, alone deserves the name of the energy-value of this change of condition. In this way the arbitrary substantial conception of the processes would be preserved and misapprehensions forestalled.