The evolution of the human race, says Nesbit, has passed from the physiological into the psychological field; and it is in the latter alone that progress may be looked for. This is the realm into which Keely's efforts, to give to the world a costless motive power, have slowly conducted him through the black darkness of the region in which he has been fighting his way, for a score of years, in behalf of true science and humanity. Lord Derby has said that modern science, on its popular side, is really a great factory of popular fallacies; that its expounders in one decade are kept busy refuting the errors to which the preceding decade has given currency. There is hardly a branch of science, he says, susceptible of general and wide-reaching conclusions, which might not be revolutionized by some discovery to-morrow. If Keely is able to establish his theories, physical science will have to abandon the positions to which she clings, and forced to admit that there exists a purity of conditions in Vibratory Physics unknown in mechanical physics, undreamed of even in philosophy; for he will then be in a position to demonstrate the outflow of the Infinite mind as sympathetically associated with matter visible and invisible. Of this philosophy Professor Daniel G. Brinton has said, "It is so simple, beautiful and comprehensive in its vibratory theory that I hope it will be found experimentally to be true. To me all commercial and practical results, motors, air-ships, engines, are of no importance by the side of the theoretical truth of the demonstrations of this cosmic force. As soon as Dr. Koenig is prepared to report on the purely technical and physical character of the experiments, I shall be, in fact I am, ready to go into full details as to their significance in reference to both matter and mind. It will be enough for me if Dr. Koenig is able to say that the force handled by Keely is not gravity, electricity, magnetism, compressed air, nor other of the well-known forces. Let him say that, and I will undertake to say what the force is." Tests were made last year by Dr. Koenig and Dr. Tuttle, a Baltimore physicist, in the presence of other men of science with the most sensitive galvanometer belonging to the University of Pennsylvania, all of whom were satisfied that no known force had been detected. The abstract of Keely's philosophy, written by Dr. Brinton, has made Keely's theories intelligible for the first time. Each new discovery necessitates a new vocabulary; and Keely's writings are obscure because of his new nomenclature. When Faraday's ideas differed from those held by the authorities of his time, they were pronounced to be "untranslatable into scientific language;" and as was then said of Faraday, so can it now be said of Keely, with equal truth, that, working at the very boundaries of our knowledge, his mind habitually dwells "in the boundless contiguity of shade" by which that knowledge is surrounded.