When all this is set up, as shown in Fig. 1, make a key and keyhole.  A 1/4 in. bolt or a large nail sharpened to a point, as at F, Fig. 3, will serve for the key.  To provide the keyhole, saw a piece of wood, I, 1 in. thick by 3 in. square, and bore a hole to fit the key in the center.  Make a somewhat larger block (E, Fig. 3) of thin wood with a 1/8-in. hole in its center.  On one side of this block tack a piece of tin (K, Fig. 3) directly over the hole.  Screw the two blocks together, being careful to bring the holes opposite each other.  Then, when the point of the key touches the tin, and the larger part (F, Fig. 3) strikes the bent wire L, a circuit is completed; the buzzer knocks catch A (Fig. 1), which rises at the opposite end and allows catch B to fly forward and release the piece of broom-stick C. The weight D then falls and jerks up the hook-lock M, which unlocks the door, and the heavier weight N immediately opens it.

Thus, with a switch as in Fig. 3, the door can only be opened by the person who has the key, for the circuit cannot be closed with an ordinary nail or wire.  B, Fig. 2, shows catch B, Fig. 1, enlarged; 0, Fig. 2, is the cut through which the rope runs; H, Fig. 1, is an elastic that snaps the catch back into place, and at G the wires run outside to the keyhole.

This arrangement is very convenient when one is carrying something in one hand and can only use the other.  Closing the door winds up the apparatus again.  —­Contributed by E. H. Klipstein, 116 Prospect St., East Orange, New Jersey.

** Parlor Magic for Winter Evenings [90] By C. H. Claudy

You are seated in a parlor at night, with the lights turned low.  In front of you, between the parlor and the room back of it, is an upright square of brightly burning lights, surrounding a perfectly black space.  The magician stands in front of this, in his shirt sleeves, and after a few words of introduction proceeds to show the wonders of his magic cave.

Showing you plainly that both hands are empty, he points with one finger to the box, where immediately appears a small white china bowl.  Holding his empty hand over this bowl, some oranges and apples drop from his empty hand into the bowl.  He removes the bowl from the black box, or cave, and hands its contents round to the audience.  Receiving the bowl again, he tosses it into the cave, but it never reaches the floor—­it disappears in midair.

The illusions he shows you are too many to retail at length.  Objects appear and disappear.  Heavy metal objects, such as forks, spoons and jackknives, which have been shown to the audience and which can have no strings attached to them, fly about in the box at the will of the operator.  One thing changes to another and back again, and black art reigns supreme.

Now all this “magic” is very simple and requires no more skill to prepare or execute than any clever boy or girl of fourteen may possess.  It is based on the performance of the famous Hermann, and relies on a principle of optics for its success.  To prepare such a magic cave, the requisites are a large soap box, a few simple tools, some black paint, some black cloth, and plenty of candles.