The end containing the movable panel being arranged, make up the rest of the box to it, taking care to make the rebates of the top and bottom frames to correspond with those of the end.
The other panels should not, however, depend on the grooves on two sides only, but at tops and bottoms as well.
FIG. 7. & FIG. 8.
The rebates are to be cut only to have all the framing inside look alike; and as the panel, B, is made to fit quite close into the rebate, it will not be surmised that it is not fitted in the usual way.
After the box is made and fitted together, the clamping must be done. The only necessity for this is in order that the bolt, D, which we have seen is made on the outside end exactly to match the screws used to fasten the clamps, should not be conspicuous, as it would be were it alone. As it is, it will not be specially observable, being apparently only one of the screws to fasten the clamps.
The clamps may be of thin brass or iron, shaped as shown at Fig. 9. One of the corner holes must be arranged to cover D exactly, and the others regulated to it. Let us suppose that A, Fig. 9, is the one through which the bolt goes; the other corner screw holes must be equally distant from the edges of the clamps. Twelve of these clamps will be needed. After they have been screwed on, put the bolt through, and let the claw of the lever hold it in place. Then mark and cut the bolt flush with the clamp, making a hollow on the end of it to imitate the screws, as D, Fig. 4. The other end of the bolt should either be made flush with the inside of frame and colored to match it, or, better, cut short and faced flush with a piece of wood to match the framing.
If a piece of wood with a knot be chosen for this side of the frame, so much the better. Immediately over the hole, L, a wooden pin should be fixed in the lid, and of such length that it will press the short arm of lever down sufficiently. It should fit the hole pretty closely.
At the other end, a corresponding pin and hole should be made, and, say, two along the front. These will then look as if they were intended merely as fittings to hold the lid in position. The lid at the other end of the box from the movable panel should have a stop of some sort; the ordinary brass joint stop will do as well as any, and should be strong. The reason for placing it at what I may call "the other end" is that, when the box is being examined, it will attract notice, and draw attention from the movable panel end.
We may now finally adjust the loose panel, which must fit tight at top and bottom, and be slightly beveled, as shown on section. Two holes must also be cut through it, at such a distance from each other that a finger and thumb can be put through them, so as to allow of the panel being moved. In the deep grooving in front also put a couple of springs, say pieces of clock springs, as shown, I, I, Fig, 2. These serve to assist the bolt, D, by pushing the panel into position.
Holes to match those in end panel must also be cut in the other panels, and when a lock, preferably a padlock, has been fitted, the box is complete.
I don't know whether it is necessary to say that the lid should be hinged at the back, and of course it will add to the appearance of the box if it be polished or oiled.
Now, for those who may not have seen the locked and corded box trick performed, a few words of caution may not be out of place. Don't forget to have something in a pocket easily got at that will serve to push the bolt out, before going into the box. A piece of stout wire, a small pencil case, or anything of that sort will do. Be careful when getting into the box to lie with your head toward the loose panel end, and face toward the front - as there will be no space to turn round; the right hand will then be uppermost and free to push the bolt out. Having done this, grasp the panel with the finger and thumb by means of the two holes, push it to the front of the box, when the back edge will be clear of the groove. It can now easily be pulled into the box, and the performer can creep out. When out, refix panel and bolt so that everything looks as it was. Any cording that may be over the end of the box will give sufficiently to allow of exit.
I have, I think, made it quite clear that padlock and ropes have nothing to do with the real performance of the trick, but they serve to mystify spectators, who may be allowed to knot the rope and seal the knots in any way they choose.
There must always be a screen or curtain to hide the box from the spectators while the performer is getting in or out. - D.B. Adamson, in Amateur Work.