such facts leads one to at least faintly comprehend the possibility of space itself disappearing from the inner planes--space as we know it. The matter of each of the planes consists of seven classes. We are familiar with the solids, liquids and gases of the physical plane, and to them must be added four grades of the ether. The seven grades of matter of the astral and mental worlds constitute an important part of the mechanism for the soul's evolution, for they determine the state of consciousness in the life beyond the physical plane. But a study of those states of consciousness belongs to a later chapter. A difficulty which the student of theosophy should make an early effort to eliminate, is the tendency to think of invisible realms as unreal. It should not be forgotten that it is only the limitation of the physical senses that gives rise to the feeling of unreality beyond the visible. We should keep in mind the fact that the invisible realms are composed of matter as certainly as the air is matter, or a stone is matter. The water in a pan may evaporate, but it does not cease to be matter because it has passed beyond the ken of the physical senses. It will some time condense once more and play its part as the liquid, water, or as the solid, ice. Only when matter is in certain forms can we know of its existence through the physical senses. We frequently hear people who are students of the occult speak of a deceased person as having left the earth. But passing into the astral plane, or world, is not, of course, leaving the earth. Both the astral world and the mental world are divisions of the earth. As the atmosphere is invisible and yet is a part of the earth's physical matter, so the invisible astral and mental regions are other parts of the earth. They are properly called worlds because the activities in consciousness that make up existence there are as remote from ours as though they were upon another planet. We have erroneously supposed that with the physical senses we really see and know the earth, whereas we have known only that small fragment of the earth that consists of physical matter. Beyond the limitation of our poor senses stretch in unsuspected grandeur vaster regions of our earth, swept by the vibrations of an intenser life. CHAPTER VI. THE MECHANISM OF CONSCIOUSNESS