It is often asked whether under these circumstances a man sees always with this abnormal sight, or only when he wishes to do so. The answer is that if the faculty is perfectly developed it will be entirely under his control, and he can use that or his more ordinary vision at will. He changes from one to the other as readily and naturally as we now change the focus of our eyes when we look up from our book to follow the motions of some object a mile away. It is, as it were, a focussing of consciousness on the one or the other aspect of what is seen; and though the man would have quite clearly in his view the aspect upon which his attention was for the moment fixed, he would always be vaguely conscious of the other aspect too, just as when we focus our sight upon any object held in our hands we yet vaguely see the opposite wall of the room as a background. Another curious change, which comes from the possession of this sight, is that the solid ground upon which the man walks becomes to a certain extent transparent to him, so that he is able to see down into it to a considerable depth, much as we can now see into fairly clear water. This enables him to watch a creature burrowing underground, to distinguish a vein of coal or of metal if not too far below the surface, and so on. The limit of etheric sight when looking through solid matter appears to be analogous to that imposed upon us when looking through water or mist. We cannot see beyond a certain distance, because the medium through which we are looking is not perfectly transparent. The appearance of animate objects is also considerably altered for the man who has increased his visual powers to this extent. The bodies of men and animals are for him in the main transparent, so that he can watch the action of the various internal organs, and to some extent diagnose some of their diseases. The extended sight also enables him to perceive, more or less clearly, various classes of creatures, elemental and otherwise, whose bodies are not capable of reflecting any of the rays within the limit of the spectrum as ordinarily seen. Among the entities so seen will be some of the lower orders of nature-spirits--those whose bodies are composed of the denser etheric matter. To this class belong nearly all the fairies, gnomes, and brownies, about whom there are still so many stories remaining among Scotch and Irish mountains and in remote country places all over the world.