It is claimed that there are about three hundred extinct volcanoes, and many facts indicate that the convulsions in the earth’s crust are much less frequent than formerly, yet one can easily conceive of its destruction by internal forces, when, as the poet has said, “The cloud-capped towers, the gorgeous palaces, The solemn temples, _the great globe itself_, Yea, all which it inherit, shall dissolve, And like the baseless fabric of a vision, Leave not a wreck behind.” Revelation clearly announces the destruction of the earth: “In the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat; the earth also and the works that are therein shall be burned up.” THE CIRCLE OF THE SCIENCES. MENTAL SCIENCE Is the mind’s knowledge of itself, of its faculties, and states. _Psychology_ is now generally accepted as the most appropriate term to indicate that knowledge, and the studies that lead to its attainment. The _psyche_, as used by those ignorant of man’s higher nature, means the vital principle supposed to animate all living bodies, whether of men or the lower animals. It is, with them, the same as _life_, and is regarded as a result of the organizations they see, and not their cause. Others more consistently hold that, even in the lowest sense, vital forces precede, secure, and determine the organisms they animate; and that in the case of man there is a nobler endowment, a superadded, distinct, self-conscious, personal intelligence. “There is a spirit in man, and the inspiration of the Almighty giveth him understanding.” This _psyche_, or living soul, is a distinct, spiritual existence, however closely, for a time, allied with matter, and acting through bodily organs. It is capable of a separate existence, and while in the body, presents for our study phenomena peculiarly its own. Intellectual processes may be more subtle, and their analysis more difficult, than that of things external, because in the attempt the mind is, at once, subject and object, the observer and the observed. And, moreover, when greatly excited, it does not submit to immediate and direct investigation, as the effort at once arrests the excited feeling, and lowers the temperature, so that the state can be analyzed only as it is remembered. But, difficult of attainment as it is, the science that discusses the mind, proposing to show all that is known or may be learned respecting it, certainly challenges the interested attention of all who desire to know themselves. Whatever may be thought of the substance, or immediate origin of the active, thinking soul, consciousness affirms its presence, and its power to know and feel. When in a calm, thoughtful state, the phenomena are as real and as manifest as anything in physics or material things that are open to scientific investigation. By thorough introspection, the inquirer finds _himself_ an invisible person, quite distinct from what is merely corporeal in