The theory of Aristotle concerning heat, viz. that it is a condition of matter, together with the dicta of Locke, Davy, Rumford, and Tyndall, have been consigned of late by many to the tomb of exploded theories, and are replaced by those of Lavoisier and Black, which make caloric an actual substance. The Rev. J. J. Smith, M.A., D.D., tells us that the only way the great problem of the universe can ever be scientifically solved is by studying, and arriving at just conclusions with regard to, the true nature and character of force. He maintains, in his paper upon "The Unity and Origin of Force," that, as it is the great organizer of matter, it must not only be superior to it, but also must have been prior, as it existed before organization commenced, and immanent always. Newton, who scoffed at Epicurus's idea that "gravitation is essential and inherent in matter," asserted that gravity must be caused by an agent acting, constantly, according to certain laws. Heat, gravity, light, electricity, magnetism, chemical affinities, are all different phases of the primal force discovered by Keely, and all these forces, it is said, can be obtained from a single ray of sunlight. "The evidence of unity or oneness even between the physical, vital, mental, and spiritual is seen in the light of this law of correlation," says Smith. "A great portion of our muscles contract and relax in obedience to our wills, thereby proving that the mental force can be, and is, in every such instance actually converted into the muscular or the physical." Keely demonstrates the truth of this assertion, claiming that "all forces are indestructible, immaterial, and homogeneous entities, having their origin and unity in one great intelligent personal will force." The Duke of Argyll says:--"We know nothing of the ultimate seat of force. Science, in the modern doctrine of conservation of energy, and the convertibility of forces, is already getting something like a firm hold of the idea that all kinds of forces are but forms or manifestations of some one central force, issuing from some one fountain-head of power." It is Keely's province to prove to materialists--to the world--that this one fountain-head is none other than the Omnipotent and all-pervading Will-Force of the Almighty, "which upholds, guides, and governs, not only our world, but the entire universe. This important truth is destined to shiver the tottering fabric of materialism into fragments at no distant day."