“We have now seen together the wonderful mysteries of the phantasmagoria. I have unveiled to you the secrets of the priests of Memphis. I have shown you every mystery of optical science; you have witnessed scenes that in the ages of credulity would have been considered supernatural. You have, perhaps, many of you, laughed at what I have shown you, and the gentler portion of my audience have possibly been terrified at many of my phantoms; but I can assure you, whoever you may be, powerful or weak, strong or feeble, believers or atheists, that there is but one truly terrible spectacle—the fate which is reserved for us all;” and at that instant a grisly skeleton was seen standing in the middle of the hall (fig. 54). [Illustration: FIG. 54.—Phantasmagoria (ROBERTSON). ] Even in those unbelieving days, when scepticism of every sort was riding rough-shod over the French people, Robertson had the greatest difficulty in disclaiming all approach to the possession of supernatural powers. Day after day he received applications from all quarters to reveal the secrets of the past, present, and future, to describe events that were passing in other countries; and it frequently happened, that after his entertainments, he would be asked by several members of his auditory to assist them in recovering property that had been lost or stolen from them. In the latter kind of cases he generally used to adopt the excellent plan of sending his would-be clients to the nearest police-office. ------------------------------------------------------------------------ CHAPTER III. OTHER OPTICAL ILLUSIONS. BY varying the disposition of mirrors, prisms, lenses, and light, an infinite number of the most surprising effects may be shown, with a comparatively small amount of trouble and expense. We shall, therefore, devote this chapter to the explanation of a large number of allusions, which have been devised by Robertson and other adepts in the art of honest deception. One of Robertson’s most famous delusions was the “Dance of Demons,” an effect he discovered quite accidentally. One evening, while experimenting with the phantasmagoria, he suddenly found himself in the dark, when two persons, each bearing a light, crossed the room on the other side of the screen. A little window which happened to be between the lights and the screen, immediately threw its double image on the cloth, and the method of multiplying shadows was discovered. [Illustration: FIG. 55.—Wizard Dance. ]