Three years previously, Rankine also had put forth some very remarkable ideas the full meaning of which was not at first well understood.

He it was who comprehended the utility of employing a more inclusive term, and invented the phrase energetics.

He also endeavoured to create a new doctrine of which rational mechanics should be only a particular case; and he showed that it was possible to abandon the ideas of atoms and central forces, and to construct a more general system by substituting for the ordinary consideration of forces that of the energy which exists in all bodies, partly in an actual, partly in a potential state.
By giving more precision to the conceptions of Rankine, the physicists of the end of the nineteenth century were brought to consider that in all physical phenomena there occur apparitions and disappearances which are balanced by various energies.

It is natural, however, to suppose that these equivalent apparitions and disappearances correspond to transformations and not to simultaneous creations and destructions.

We thus represent energy to ourselves as taking different forms--mechanical, electrical, calorific, and chemical-- capable of changing one into the other, but in such a way that the quantitative value always remains the same.