The author then goes on to give minute directions for performing the ceremonies necessary for raising the Devil, so to speak, with which we have nothing to do at present; these quotations being made merely for the purpose of showing that the greatest and most philosophical magician of this century was fully aware that the shapes evoked by the Magi, whether they be of angels or of demons, whether they be perceptible to the objective senses or merely subjective hallucinations, tangible or intangible, are the creations of the mind of the magician. The phenomenon of crystal vision is another illustration of the power of the subjective mind to create visions. Ordinarily these visions are only perceptible to the operator; but cases are recorded where they were perfectly perceptible to the bystanders. The conditions necessary for successful crystal reading are practically the same as in all other cases, although the subjective condition is not ordinarily so pronounced. This phenomenon illustrates, however, the power of the subjective mind to create phantasms, and constitutes one of the many methods of bringing the operations of the subjective mind above the threshold of consciousness. It is one of the best methods known of exercising the power of telepathy, the visions being objective reproductions of what is real or perceived in the mind of the person who consults the medium. If no one is present besides the medium or operator, he sees merely what his own subjective mind creates. It is perhaps superfluous to remark that the phenomenon is governed by the same laws which pertain to all other subjective phenomena, and the intelligence displayed is hedged about by the same limitations. I have now enumerated several different sub-classes of the phenomena which are concerned in the creation of visions. In each sub-class instances are recorded of the visions being made perceptible to the objective senses of others. As remarked in the beginning of this chapter, we do not propose to stop to verify the phenomena of each class. It is sufficient to know that the phenomena of one of the sub-classes is verified by scientific authority. For present purposes the rest must stand or fall by that. At any rate, we shall assume the right to hold that any cognate phenomenon, alleged to have been produced under the same conditions as those which have been demonstrated to be veridical, is entitled to tentative consideration and credit. It is assumed, therefore, that the following propositions are sufficiently verified for the purpose of formulating a definite theory of proximate causation:-- 1. The alleged phenomena are all produced under the same conditions. 2. The one essential condition is that of the partial or total suspension of objective consciousness. 3. The more complete the extinction of the objective consciousness, the more pronounced the success of the experiment; that is, the more tangible to the objective senses of others do the creations become.