Buckle has asserted that the highest of our so called laws of nature are as yet purely empirical; and that, until some law is discovered which is connected with the laws of the mind that made it, our knowledge has no sure basis. So saturated has Mr. Keely's mind been with his discovery of this law that he has contented himself to remain ignorant in physics, as taught by the schools; and also with simpler matters it would seem; while testing and building up his hypotheses into a system which no one but himself can complete, and which without completion must be lost to the world. I should form a very poor opinion of the mind that would accept an hypothesis as anything more than the signpost at cross roads, which points to the direction that may be taken. In physics the very first fact to which the learner is introduced is already sophisticated by hypotheses. Every experiment in chemistry is but a member of a series, all based upon some one or other of many hypotheses; which are as necessary to the construction of a system as is the scaffolding which is used in building an edifice. If the scaffolding proves unsound it does not affect the edifice, as it can be at once replaced with material more solid. So an hypothesis, which is merely a conjecture or a suggestion, cannot affect the solidity of a philosophy or a system. It must be tested and found to support all the facts which bear upon it, and capable of accounting for them, before it can be accepted as a theory. It is my wish to have the professors of the University of Pennsylvania meet at my house the founder of a system which, in my opinion, embraces a pure philosophy: to listen to his theories, and to elicit from him such information as to the nature of his researches, in what is called electro-magnetic radiation, as I trust will convince them that I have not been pursuing a will-o'-the-wisp during the years that my mind has been concentrated on the work in which Mr. Keely is engaged. The bearings of this work are so various that I shall not have time to touch upon more than the one which interests me beyond any or all of the others; namely, its connection with the medical art. Appreciating as I do the life of self-denial which physicians who are devoted to their profession must lead, and having in their ranks relatives and many warm friends on both sides of the ocean (one of them, my nephew, Dr. Jessup, is here to-night) I trust that what I say of the medical art will not be misconstrued.