It is difficult to imagine to what a pitch audacity of certain tricksters will carry them. I once attended a series of experiments, which interested me greatly from that point of view. The group included three young men, one of whom is a most remarkable medium. The other two, intelligent and well-educated young fellows, appeared to me to have some medianic faculties, but I withhold my judgment, because they tried so hard to cheat, that it would not be prudent to seriously notice those facts, where fraud did not strike me as coming into play; for it was always possible. These young men had nothing to gain by cheating; in any case, I have not yet understood what aim they wished to attain. The levitations of the table were splendid—in obscurity—and all the furniture in the seance-room was more or less jostled about and displaced. This was all very fine; it was all very well done; and novices were easily taken in. The ‘spirits’ caressed or struck the sitters, and I have seen sincere but inexperienced persons convinced of the reality of facts, for which the legerdemain of one of the young men present was alone responsible. One of these youths, a medical student, presents symptoms of nervous troubles, and will become a hysteric if he is not one already. Notwithstanding my reproaches and exhortations, he could not stop himself from cheating; and I have the impression that fraud is, in his case, almost impulsive. I did not think I was authorised to examine him from a medical point of view, but I observed him carefully. He has manufactured spirit photographs very cleverly; they were wonderfully well done, and only a professional eye would detect the trick. He proceeded by double exposure. With this group, as soon as the room was lighted up, the phenomena, which were so violent in obscurity, ceased almost entirely. This circumstance alone was suspicious; for the action of light is not such as to constitute an insurmountable obstacle to the production of telekinetic movements. Whenever phenomena are intense in obscurity, we ought to be able to obtain weaker ones of the same kind in light. This is a rule without an exception, as far as my experience goes. Needless to add that the table, under the normal impetus which the young men gave it, insisted upon total darkness. Now, in truly good seances, on the contrary, I have always seen the table ask for light, if purely motor phenomena were desired. Naturally, it is otherwise with luminous phenomena, of which I am now going to speak. CHAPTER IV LUMINOUS PHENOMENA The curious glimmering lights, which I am going to describe in this chapter, can only be obtained in total obscurity. They are generally feeble, and appear to be at the limit of visibility. I will begin by describing a rather curious phenomenon, which is easily observable. I am not quite sure of its objective reality; nevertheless, I will point it out, and give my reasons for doing so.