Note 756 — Chapter V · (continued 2)

The theory of the indestructibility of force has been applied to the law of gravitation by Professor Faraday, in his Discourse on the Conservation of Force, 1857; an essay full of thought and power, and which should be carefully studied by every one who wishes to understand the direction which the highest speculations of physical science are now taking. I will quote only one passage from the opening, to give the reader an idea of its general scope, irrespective of the more special question of gravitation. ‘The progress of the strict science of modern times has tended more and more to produce the conviction that force can neither be created nor destroyed; and to render daily more manifest the value of the knowledge of that truth in experimental research.’ … ‘Agreeing with those who admit the conservation of force to be a principle in physics, as large and sure as that of the indestructibility of matter, or the invariability of gravity, I think that no particular idea of force has a right to unlimited or unqualified acceptance, that does not include assent to it.’