Modern Magic: A Practical Treatise on the Art of Conjuring

A closer inspection of the target, which is sometimes of wood, but more often of tin, japanned, would disclose the fact that the bull’s-eye is moveable, revolving perpendicularly on its own axis. It is coloured alike on both sides, and each side is provided with such a hook as already mentioned, so that whichever side of the bull’s-eye is for the time being level with the face of the target, no difference is perceptible to the spectator. There is a little projecting pin, or stop, at one point of the diameter of the bull’s-eye, which prevents its making more than a half revolution, and a little spiral spring, attached to one of the two pivots on which it moves, compels it to turn, when at liberty, always in one particular direction until stopped by the pin, so that its normal condition is to have one particular side, which we will call, for greater clearness, side a, always turned towards the face of the target. The bull’s-eye may, however, be turned round, so that the opposite side, b, is towards the face of the target, and there is a little catch which retains it as so turned; but the instant the catch is withdrawn, the action of the spring makes it fly round again to its old position. The catch is released by means of a stiff wire passing through the pillar on which the target rests, and terminating in a round disc of metal in the foot. The mode of connection between the wire and the catch varies according to the fancy of the maker; but, whatever this may be, the catch is invariably released by an upward pressure of the disc from below. If the target is held in the hand of the assistant, this is effected by the direct pressure of the fingers; but in stage performances, where the target is placed on a table, this, as indeed almost every other mechanical piece, is set in motion by the upward movement of a wire rod (known as a piston), made, by the pulling of a string, to rise through the upper surface of the table.