I know that Madame Blavatsky, in alluding to the theory of the fourth dimension, has expressed an opinion that it is only a clumsy way of stating the idea of the entire permeability of matter, and that Mr. W. T. Stead has followed along the same lines, presenting the conception to his readers under the name of _throughth_. Careful, oft-repeated and detailed investigation does, however, seem to show quite conclusively that this explanation does not cover all the facts. It is a perfect description of etheric vision, but the further and quite different idea of the fourth dimension as expounded by Mr. Hinton is the only one which gives any kind of explanation down here of the constantly-observed facts of astral vision. I would therefore venture deferentially to suggest that when Madame Blavatsky wrote as she did, she had in mind etheric vision and not astral, and that the extreme applicability of the phrase to this other and higher faculty, of which she was not at the moment thinking, did not occur to her. The possession of this extraordinary and scarcely expressible power, then, must always be borne in mind through all that follows. It lays every point in the interior of every solid body absolutely open to the gaze of the seer, just as every point in the interior of a circle lies open to the gaze of a man looking down upon it. But even this is by no means all that it gives to its possessor. He sees not only the inside as well as the outside of every object, but also its astral counterpart. Every atom and molecule of physical matter has its corresponding astral atoms and molecules, and the mass which is built up out of these is clearly visible to our clairvoyant. Usually the astral of any object projects somewhat beyond the physical part of it, and thus metals, stones and other things are seen surrounded by an astral aura. It will be seen at once that even in the study of inorganic matter a man gains immensely by the acquisition of this vision. Not only does he see the astral part of the object at which he looks, which before was wholly hidden from him; not only does he see much more of its physical constitution than he did before, but even what was visible to him before is now seen much more clearly and truly. A moment's consideration will show that his new vision approximates much more closely to true perception than does physical sight. For example, if he looks astrally at a glass cube, its sides will all appear equal, as we know they really are, whereas on the physical plane he sees the further side in perspective--that is, it appears smaller than the nearer side, which is, of course, a mere allusion due to his physical limitations.