The explanation of the device is made simple by the enlarged [cross section]. To the two rollers journaled in the standards are attached the ends of a strip of black cloth which is wound around both rollers in opposite directions, so as to about evenly divide the cloth between the rollers. The gudgeons of the rollers are squared to receive an ordinary clock key, by means of which either may be turned. To prepare the machine for operation, the cloth is wound upon one of the rollers while it is partly unwound from the other; then the key is transferred to the gudgeon of the partly filled roller, and as it is turned, crisp new bank bills are fed into the machine and are wrapped with the black cloth upon the roller between the convolutions of the cloth; one bill after another is thus inserted until three, four, or more bills are hidden in the roll, and the rollers present about the same appearance as to size. This preparation, of course, takes place aside, and is not seen by the persons to whom the trick is to be shown. The key is shifted from the roller containing the bills (the upper one in the present case) to the lower one. Now, as the lower roller is turned so as to unwind the cloth from the upper roll, a piece of plain paper of the width and length of a bank note is inserted at the moment the first bill is about to emerge from the layers of cloth on the upper roll. The paper begins to be rolled upon the lower roll under the outer layer of cloth, so that while the paper appears to be simply rolled through between the rollers, coming out upon the opposite side a complete bill, it is in reality only hidden by the cloth on the lower roller. After the first bill is discharged from the rollers another piece of paper must be supplied in such a manner that it will begin to enter the machine as the next bill emerges, and so on.
EXPERIMENTS IN CENTRIFUGAL FORCE AND GRAVITY.
The elasticity of torsion and tension, the storage of energy, centrifugal force, momentum, and friction are all concerned in the movement of the simple toy illustrated in [Fig. 1]; and yet, perhaps, not one in a thousand of the people who see the toy realizes the composite nature of its action. Barring the well-known return ball, nothing can be simpler than this toy, which consists of two wooden balls of the same diameter connected by a slender rubber band attached by staples, as shown in the lower figure.
FIG. 1.—GYRATING BALLS.
To prepare the toy for operation, it is only necessary to twist the rubber band by holding one of the balls in the hand and rolling the other round in a circular path upon the floor by giving to the hand a gyratory motion. As soon as the band is twisted, the free ball is grasped in the hand, then both are released at once.
The untwisting of the rubber band causes the balls to roll in opposite directions in a circular path, and centrifugal force causes the balls to fly outward. By virtue of the acquired momentum, the balls continue to rotate after the rubber band is untwisted, so that the band is again twisted, but in the opposite direction. As soon as the resistance of the band overcomes the momentum of the balls, the rotation ceases for an instant, when the band again untwisting revolves the balls in the opposite direction, and the operation is repeated until the stored energy is exhausted.