Modern Magic: A Practical Treatise on the Art of Conjuring

The trap for this purpose is a somewhat complicated arrangement, of the appearance shown in Figs. 270 and 271. The surface-plate, a a a a, is oblong, measuring about twelve inches by six, with a circular opening b b in the centre. Below it are fixed vertically two brass cylinders c and d, which are so arranged as to work backwards and forwards on a kind of railway e f e f, in the direction of the length of the surface-plate, just so far in either direction as to bring c or d in turn immediately under b. The two cylinders are soldered together, so that the one cannot move without the other. If, therefore, the cylinders are drawn back to the utmost by means of one of the bent iron rods or handles g h, the cylinder c will be below the opening b, as in Fig. 272. If, on the contrary, they be pushed forward, d will in turn be below the opening, as in Fig. 273. Each cylinder contains a brass piston, faced with zinc on its upper surface, and moved up and down by a lever attached at right angles to one or other of the iron handles g h already mentioned, and working through a vertical slot in the side of the cylinder. A piece of clock-spring, attached to the iron handle at the point of junction, gives the piston a gentle upward tendency, which is so regulated, that if either of the cylinders be brought under the opening b, the piston belonging to that cylinder is made to rise into the opening, its upper surface resting just flush with that of a a a a. The piston of the forward cylinder c is made to work very easily within it, so as to rise spontaneously by the action of the spring; but that of the hinder cylinder, d, for a reason which will presently appear, works a little more stiffly, so as to require a little assistance from the lever to make it rise into its proper position. The action of the handles g h is outwards, in the direction of the arrows in Fig. 274, the movement of either handle in the direction so indicated drawing down the piston to which it belongs.