Force is an attribute of mind or spirit, and of mind or spirit alone. Spirit-force is the only force in the universe. It is a doctrine as old as the hills that mind is the first cause of motion. Νοῦς μὲν ἀρχὴν κινησέως.[338] It is a doctrine toward which all modern science tends with remarkable unanimity that all motion is the product of mind; and, though continued and transformed and transmitted through various means, it never commences except in a volition either of the Supreme Mind or of a created mind. "The deep-seated instincts of humanity and the profoundest researches of philosophy alike point to _Mind as the one and only source of power_."[339] "The conception of force as the originator of motion in matter, without bodily contact or the intervention of any intermedium, is essential to the right interpretation of physical phenomena;... its exertion makes itself manifest to our personal consciousness by the peculiar sensation of _effort_;... and it [force] affords a point of contact, a connecting link between the two great departments of being--between mind and matter--the one as its _originator_, the other as its _recipient_."[340] 3. All the forms of energy manifested in the universe are only transformations of the one omnipresent force issuing from the one fountain-head of power--_the Divine Will_. The final disclosure of modern science is the convertibility and homogeneity of all forms of physical energy--"a dynamical self-identification masked by transmigration." Of this wonderful transformation of energy many striking illustrations may be given; we select the following from the "Lecture Notes" of Dr. A. F. Mayer (p. 64): "The heat developed by the 'falling force' of a weight striking the terminals of a compound thermal battery (formed by pieces of iron and German-silver wire twisted together at alternate ends) caused a current of electricity through the wire which, being conducted through a helix, magnetized a needle (which then attracted iron particles), caused light to appear in a portion of the circuit formed of Wollaston's fine wire, decomposed iodide of potassium, and finally moved the needles of a galvanometer."[341] Here we have visible kinetic energy transformed into sensible heat, then absorbed heat converted into electricity, then electricity transformed into magnetism, also into light, and still further into the energy of chemical separation, while some portion of it returns to the form of visible energy of motion. Of course, some of the energy is dissipated in the form of radiance (radiant light and heat), but no energy is either created or destroyed. All the various forms of energy are thus reducible to _unity_; they are one force transformed by mechanical arrangements. "Electricity and magnetism, heat and light, muscular energy and chemical action, motion and mechanical work, are only different forms of one and the same power.... Moreover, chemical union of the elements of matter,