William Bower Taylor

“ In defining atoms as centers of pressure, they are thus no less distinguished on the one hand from centers of force than from the little hard bodies of the ordinary theories; for such centers of force are just as absolute and self-existent in the ordinary conception of them as those little bodies ; and in a scientific theory there can (except as temporary conveniences) be no absolute existences, entities. Hence (mechanical) force, or the cause of motion, is conceived not as an entity but as a condition, — the condition namely of a difference of pressure ”

“ Commencing with the generalization that " a mechanical force, or the cause of a mechanical motion, we know to be in general the condition of a difference of pressure," he infers, "hence it appears that if a general mechanical theory is possible, the ultimate property of matter must be conceived to be a mutual repulsion of its parts, and the indubitable Newtonian law of universal attraction be deduced herefrom, under the actual conditions of the world. ”

“ This is the fundamental conception (not hypothesis) of the theory.... Now in a system of atoms as above defined, let the centers be of equal mass and at equal distances; there will be no difference of pressure on any one center, no moving force will be developed, and the conditions of equilibrium will be satisfied. ”