FIG. 3.—THE INVISIBLE GIRL EXPERIMENT.
Fig. 2 shows the arrangement of the original apparatus, which consisted of a glass case, X, about four feet long by about one in height, suspended from the ceiling by four chains at a distance of a foot from the window frame. From the extremity of the case projected a speaking trumpet, and the entire apparatus was surrounded by a latticework of iron wire to prevent its being touched by the hands of the curious. The phenomenon, although a puzzling novelty at the time, did not attract much of a crowd, as it was not managed with sufficient address, and the surroundings were not of a nature to please fashionable people. This apparatus was improved upon and rendered more elegant in appearance by Prof. Robertson. Fig. 3, copied from an old engraving, shows this latter arrangement. A globe, A, made of glass or enameled sheet iron, and to which are attached four trumpets, is suspended from the middle of the room. This globe is not necessary for the experiment, but is only an accessory to impose upon the imagination. Around it is placed a framework, B, which is very necessary, for it is hollow, and it is through it that the voice of the invisible person is heard. A tin tube passes through the upright C and then runs to D, where there is a small slit or aperture opposite the trumpet. This tin tube passes under the floor of the room, and runs into the neighboring room, whence the pretended invisible person speaks, and sees everything through the keyhole or through an aperture in the wall. This is all there is of the mystery.
An Improved Psycho.
Let me explain to those who have not seen “Psycho” that it consists of a small figure dressed as a Turk, sitting cross-legged (as shown by dotted lines) on a chest; this chest is in turn supported on a glass tube, about 12 in. in diameter and 3 ft. long, which rests on a four-legged stool. The bottom of chest and top of stool are covered with green cloth, so as to make a tolerably air-tight joint. The right arm is extended as per drawing, and a semicircular rack, in which are placed the 13 cards dealt to “Psycho,” is fixed by means of a bracket (not shown) in such a position that the edges come between the finger and thumb, as shown at *. The arm turning horizontally on the pivot A, the hand can be brought over any card, and by closing the finger and thumb and raising the arm the card will be withdrawn from the rack and held in the air.
FIG. 1. a.
FIG. 1. b.
In Figs. 1a and 1b (elevation and plan) the wheels E and M have each a train of clockwork (left out for the sake of clearness), which would cause them to spin round if unchecked. M, however, has two pins, p p′, which catch on a projection on the lever, N. E is a crown-wheel escapement—like that in a bottle roasting-jack—which turns A alternately to the left and right, thus causing the hand to traverse the 13 cards. A little higher on A will be seen a quadrant B (see plan) near the edge of which are set 13 little pins. The end of the lever N drops between any two of them, thus causing the hand to stop at any desired card. The lever being pivoted at c it is obvious that by pressing the end, N, B will be set at liberty, and the hand will move along the cards; by slightly raising it this motion will be arrested; by raising it still more the pin p is released and M commences to revolve, and by again depressing N this wheel will in its turn be stopped. Near the bottom of the apparatus is a bellows O, which contains a spring tending to keep the lever N, with which it is connected by a rod X, in the position shown. This is connected with the tubular support, which may be connected by a tube through the leg of the stool, and another tube beneath the stage, with an assistant behind the scenes. By compressing or exhausting air through this tube it is obvious that the lever, N, will be raised or depressed, and the clockwork set going accordingly. a is a crankpin set in M, and connected with the head by catgut, T, and with the thumb by S.