A treatise of 1875 on the 'principle of continuity', which attempted to prove the immortality of the soul.In this second edition (1875), of their treatise, P. G. Tait and the Balfour Stewart claim that science and religion could agree on such matters as the immortality of the soul on the basis of the law of the conservation of energy operating between the visible and the invisible realms.In this second edition (1875), of their treatise, P. G. Tait and the Balfour Stewart claim that science and religion could agree on such matters as the immortality of the soul on the basis of the law of the conservation of energy operating between the visible and the invisible realms.In 1875, the geophysicist Balfour Stewart and the mathematician P. G. Tait published the second edition of The Unseen Universe. The book's aim had been 'to overthrow materialism by a purely scientific argument', and its initial success, and the controversy it aroused, prompted this revised edition. The treatise suggests that science and religion could be reconciled, and that by using science, it could be proved that the soul survives after death. The book begins with a historical account of the beliefs about the afterlife of ancient Egypt, the Greeks, Buddhism and Christianity. The authors then refine a Ptolemaic vision of the universe in which the material universe is surrounded by concentric, invisible universes. The Unseen Universe discusses the nature of matter and ether, Newton's laws, and the idea that, through electromagnetism, the soul upon death transfers molecularly from the visible to the invisible universe.Preface to the Second Edition; Preface to the First Edition; 1. Introductory sketch; 2. Position taken by the authorsphysical axioms; 3. The present physical universe; 4. Matter and ether; 5. Development; 6. Speculations as to the possibility of superior intelligences in the visible universe; 7. The unseen universe.