In his _Fragments of Science_ Tyndall makes the following sad confession: “If you ask me whether science has solved, or is likely in our day to solve the problem of this universe, I must shake my head in doubt.” If moved by an afterthought, he corrects himself later, and assures his audience that experimental evidence has helped him to discover, in the opprobrium-covered matter, the “promise and potency of every quality of life,” he only jokes. It would be as difficult for Professor Tyndall to offer any ultimate and irrefutable proofs of what he asserts, as it was for Job to insert a hook into the nose of the leviathan. To avoid confusion that might easily arise by the frequent employment of certain terms in a sense different from that familiar to the reader, a few explanations will be timely. We desire to leave no pretext either for misunderstanding or misrepresentation. Magic may have one signification to one class of readers and another to another class. We shall give it the meaning which it has in the minds of its Oriental students and practitioners. And so with the words _Hermetic Science_, _Occultism_, _Hierophant_, _Adept_, _Sorcerer_, etc.; there has been little agreement of late as to their meaning. Though the distinctions {xxiii} between the terms are very often insignificant—merely ethnic—still, it may be useful to the general reader to know just what that is. We give a few alphabetically. ÆTHROBACY, is the Greek name for walking or being lifted in the air; _levitation_, so called, among modern spiritualists. It may be either conscious or unconscious; in the one case, it is magic; in the other, either disease or a power which requires a few words of elucidation. A symbolical explanation of æthrobacy is given in an old Syriac manuscript which was translated in the fifteenth century by one Malchus, an alchemist. In connection with the case of Simon Magus, one passage reads thus: “Simon, laying his face upon the ground, whispered in her ear, ‘O mother Earth, give me, I pray thee, some of thy breath; and I will give thee mine; _let me loose_, O mother, that I may carry thy words to the stars, and I will return faithfully to thee after a while.’ And the Earth strengthening her status, none to her detriment, sent her genius to breathe of her _breath_ on Simon, _while he breathed on her_; and the stars rejoiced to be visited by the mighty One.” The starting-point here is the recognized electro-chemical principle that bodies similarly electrified repel each other, while those differently electrified mutually attract. “The most elementary knowledge of chemistry,” says Professor Cooke, “shows that, while radicals of opposite natures combine most eagerly together, two metals, or two closely-allied metalloids, show but little affinity for each other.”