In attempting to explain this second type of clairvoyance along these lines, there seem to be two main difficulties involved and these are admittedly very great. First, how is it that the four space vehicle possesses organs capable of perceiving three space objects and incidents? One would expect it to respond to four space impressions only. Secondly, as soon as the distances involved become more than quite small it is very difficult to conceive how the percipient can simultaneously describe the events by the use of physical speech mechanism and also perceive them from a point of view which must be supposed to be very considerably removed in the direction of the fourth dimension. A correspondent of my own who appears to possess this power of clairvoyance at a distance in a remarkable degree and to be able to exercise it at will, tells me that when she is seeing a distant scene, she is yet so closely in touch with her physical body that she is conscious of moving her hand, for example. It is difficult to account for this on the four dimensional or any other theory. I have no wish to minimise these difficulties or to claim that the introduction of the Higher space hypothesis clears up the whole matter. It does nothing of the sort. But it does give us a dim inkling of what the general nature of the causes at work may be, especially as regards the power of "internal vision" mentioned above and which I particularly wish to emphasise. This is more than can be said of any alternative theory with which I am acquainted. Future study will probably show that this class of phenomena is far from simple and is really capable of being resolved into a number of sub-classes, each requiring its own appropriate explanation. It is interesting to note that Mr. C.W. Leadbeater, the well-known Theosophical writer and clairvoyant, definitely introduces the four-dimensional concept in his book on Clairvoyance and ascribes the power of long-range perception to the intervention of what he calls an "astral telescope"; but there would appear to be no evidence in support of this idea beyond the _ipse dixit_ of the writer and even he is very vague on the point. The third form of clairvoyance, namely, the perception of non-physical things, is readily explicable on the hypothesis which we are considering. Just as the physical body has sense organs adapted for the perception of physical things, so the four-dimensional body or "vehicle" will presumably possess analogous organs adapted for the perception of four-dimensional things. In ordinary persons, we must suppose either that these organs are almost completely undeveloped, or else that the mechanism, whereby the impressions received are conveyed to the consciousness and recorded as memories, is defective or inhibited. In the clairvoyant on the contrary we may suppose that they are well developed and active and that he is able consciously to perceive by their aid.