As has already been said, Keely's researches have all been on the line of vibrations; and it was while pursuing them that he "stumbled over," to use his own words, the inter-atomic subdivision of the molecule, which released the Geni that for years thereafter was his master. Keely's attention not having been turned to molecules and atoms, he was not able, in the earliest years of his discovery of the existence of a "force of nature more powerful and more general even than electricity," to form any opinion as to the origin of the force. He was as one who, in the thick darkness of an underground labyrinth, found himself face to face with a giant, whose form even he could not see to lay hold of in a death grapple; but when a germ of the knowledge that he needed fell on his mind, he was quick to seize it, and the acorn grew into an oak. Here again, to use his own words: "I was as a boulder resting on the summit of a mountain, until an introductory impulse was given to start it on its course; then rushing onwards and carrying all before it, when the goal is reached its concussion will produce the crash that will awaken a sleeping world." Priestley proclaimed it as his belief that all discoveries are made by chance; but Providence sends chance, and the man of genius is he who is able to improve all opportunities and mould them to his own ends. In a discovery, says Edison, there must be an element of the accidental, and an important one too; discovery is an inspiration, while an invention is purely deductive. The story of the apple dropping from the tree, and Newton starting with a species of "Eureka," he rejects absolutely. Maintaining that an abstract idea or a natural law may, in one sense, be invented, he gives it as his opinion that Newton did not discover the theory of gravitation, but invented it; and that he might have been at work on the problem for years, inventing theory after theory, to which he found it impossible to fit his facts. That Keely claims to have discovered an unknown source of energy has not seemed to disturb the equilibriums of some of the men of science who have witnessed the demonstrations of the force, as much as that he should have invented theories in regard to the operation of the laws that control it. For a man who had lived more than half a century without troubling himself as to the existence of molecules and atoms to suddenly awaken to the knowledge of their existence, and to invent theories as to "what sort of things they are and how they vibrate," was sufficient proof, in their eyes, that he invented his discovery; but men who are, in thought, reaching out into unknown realms, are the very men who are most likely to lay hold of a discovery;--as did Bell, who, speculating upon the nature of sound, filed an invention for his telephone before he discovered that articulate speech could be conveyed along a wire. It was in the same way that Keely, speculating