Modern Magic: A Practical Treatise on the Art of Conjuring

The opposite edge of the top of the box is arranged as follows: b b is a metal tube, with an opening of about half-an-inch in length between d d; c c are two metal hooks or rings by which the apparatus is suspended, and through which the current passes. Each of these communicates with a piece of insulated copper wire, extending from c to d. The space between d d is filled up by a round plug or pencil of wood (see enlarged view in Fig. 310), along which lies a small piece of very fine platinum wire e e, connecting the ends of the two copper wires. The moveable glass flap is held up against the top by means of a little piece of black cotton f, which, passing through a minute hole in the outer edge of the flap, is made to pass round the wooden plug, and thus to cross the platinum wire at right angles, and in immediate contact with it. The practical application of the scientific principle to which we have alluded will now be obvious. At the moment of completing the circuit, the platinum, becoming red-hot, instantly severs the cotton, when down falls the flap, not altering in the least the general appearance of the box, but allowing the half-crowns to fall loose into its interior. In order to prepare the apparatus for use, it is necessary first to remove the sliding lid, to place the moveable flap in position, and to fasten it with cotton as already described. The lid should then be turned upside down, and the half-crowns placed in position, after which the box also is turned upside down, and the lid allowed to slide gently into its place. The half-crowns are now secure, and the box may be brought forward and set swinging, without any danger of their making a premature appearance.