dollar is hollow and the other fits into it; that the box has a double bottom; that the nail has been substituted for one that fits around the finger, and that one half of the card is printed on flap which by falling down shows another aspect. All these are technical devices which amuse us by the ingenuity of their construction and provoke about the same kind of mental interest as does a puzzle or an automaton. Ignorance of this technical knowledge or lack of confidence in its existence may convert these devices into real deceptions by changing the mental attitude of the spectator. However, the plausibility of such performances depends so much upon their general presentation that they seldom depend for their effectiveness solely upon the objective appearances they present. Asking the reader, then, to remember the very great number and ingenuity of such devices, and insisting once more that the only complete safeguard against being deceived by them is the acquisition of the purely technical knowledge that underlies their success, I will cite in detail a trick combining illustrations of several of the principles to be discussed. A number of rings are collected from the audience upon the performer's wand. He takes the rings back to the stage and throws them upon a platter. A pistol is needed, and is handed to the performer from behind the scenes. "With conspicuous indifference he hammers the precious trinkets until they fit into the pistol. A chest is hanging on a nail at the side of the stage. The pistol is fired at this chest, which is thereupon taken down and placed upon a table toward the rear of the stage. The chest is unlocked and found to contain a second chest. This is unlocked and contains a third; this a fourth. As the chests emerge they are placed upon the table; and now from the fourth chest there comes a fifth, which the performer carries to the front of the stage and shows to contain bonbons, around each of which is tied one of the rings taken from the audience. The effect is indescribably startling. Now for the real modus operandi. In the hand holding the wand are as many brass rings as are to be collected. In walking back to the stage the genuine rings are allowed to slip off the wand and the false rings to take their places. This excites no suspicion, as the walking back to the stage is evidently necessary, and never impresses one as part of the performance. The pistol is not ready upon the stage, but must be gone for, and as the assistant hands the performer the pistol, the latter hands the assistant the true rings. The hammering of the rings is now deliberately undertaken, thus giving the assistant ample time to tie the rings to the bonbons, and, while all attention is concentrated upon the firing of the pistol, the assistant unobtrusively pushes a small table on to the rear of the stage. This table has a small fringe hanging about it, certainly an insignificant detail, but none
