A hypothetical theory is necessary, as a preliminary step, to reduce the expression of the phenomena to simplicity and order before it is possible to make any progress in framing an abstractive theory.

A hypothetical theory is necessary, as a preliminary step, to reduce the expression of the phenomena to simplicity and order before it is possible to make any progress in framing an abstractive theory.

The words 'theory' and 'practice' are of Greek origin; they carry our thoughts back to the ancient philosophers by whom they were contrived, and by whom they were also contrasted and placed in opposition, as denoting two mutually conflicting and mutually inconsistent ideas. ... [this fallacy] based on a double system of natural laws retarded for centuries the development of physical science, notably mechanics.

Discrepancy between theory and practice, which in sound physical and mechanical science is a delusion, has a real existence in the minds of men; and that fallacy, through rejected by their judgments, continues to exert and influence over their acts.

This law (regarding the theoretical efficiency of heat engines by Mr. Joule), and the law of the maximum efficiency of heat engines, are particular cases of a general law which regulates all transformation of energy, and is the basis of the Science of Energetics.

In thermodynamics as well as in other branches of molecular physics , the laws of phenomena have to a certain extent been anticipated, and their investigation facilitated, by the aid of hypotheses as to occult molecular structures and motions with which such phenomena are assumed to be connected. The hypothesis which has answered that purpose in the case of thermodynamics, is called that of "molecular vortices," or otherwise, the "centrifugal theory of elasticity.

The hypothesis of molecular vortices is defined to be that which assumes - that each atom of matter consists of a nucleus or central point enveloped by an elastic atmosphere, which is retained in its position by attractive forces, and that the elasticity due to heat arises from the centrifugal force of those atmospheres revolving or oscillating about their nuclei or central points.According to this hypothesis, quantity of heat is the vis viva of the molecular revolutions or oscillations.