"I have at last brought you to the point of my narrative," he continued, rising, "where the chief interest may be said to begin. It has seemed best to touch on many points which may have appeared of little or no importance, and to leave out a few which you might have considered more interesting. It is a far more difficult matter than you can well understand, to deal in an intelligible manner with the forces brought into play through an unrecognized sense; especially as we have at present no names either for its effect upon the mind, or for the subjects of which, through the medium of its power, we are for the first time conscious. I propose, therefore, before continuing my story, to show you a few experiments, and to throw as much light as possible on the remarkable changes in our whole life, which a perfect knowledge of this sixth sense would bring about." "First," he continued, throwing back the curtain, "you, in your condition, are permanently tied to what we call the body, and bound down to its limitation. You can see only by the aid of light, and your vision cannot pass through what we call opaque substances. The reason why the animal eye is thus constructed must be obvious. Had it been formed in such a way as to enable it to focus only on the object it wished to observe, and were able to disregard any material obstruction which lay in the way, an animal would dash into the intervening material, even as a bird strikes itself against a clear sheet of glass. "It was doubtless for this reason that nature mercifully deals but seldom in transparent solids, allowing the eye only to penetrate matter in its liquid or gaseous forms. But you must not for a moment suppose that there is anything more miraculous in a vision which is constructed in such a way that it can reverse the process, one form being as easily developed as the other. Moreover, what we call solid, is only the term for describing matter which in its present condition resists the pressure of other material bodies to a certain extent. For as we know, heat, electricity, sound, etc., can pass even through steel. "Now, if you will come this way, I will show you an instrument which was perfected by me some years ago, but which I no longer require to use; it may possibly explain my meaning more fully. "Here," said Sydney, pointing to a small instrument which looked like a very delicate binocular telescope, "is an invention of lenses which neutralizes the effect of the greater part of the services of the eye on the brain. It is very imperfect, but it will do as an example. I will focus it at twenty yards from here, and turn it in this direction. Now what can you see?" I looked through, and saw a servant in the dining-room removing some of the things off the table. "That is a wonderful invention," I said. "Why have you never made it known?"