Modern Magic: A Practical Treatise on the Art of Conjuring

The key is then again turned as if unlocking the box, when the tail of the bolt catches the stud, and secures the flap. The box will in this condition bear any amount of examination, but as soon as it is closed, and the key turned to lock it, the tail of the bolt, being again shot forward, no longer retains the stud, and the flap falls. When in actual use, a card (say the ace of spades) is placed upon the flap, and folded up with it against the front of the box. The card to be changed (suppose the nine of diamonds) is in due course openly placed in the box, which is then handed to some one with a request that he will himself lock it, that there may be no possibility of deception. The trick proceeds, and when the box is again opened, the card placed therein is found transformed to the ace of spades. Some card-boxes are so made, that the flap, instead of falling actually upon the bottom of the box, falls parallel to it, but at a distance of an inch or so above it, leaving a hollow space beneath capable of containing a lady’s handkerchief, a canary, or any other small article, which, being covered by the falling flap, is thus apparently changed into a card. The box in this case is somewhat taller in proportion than that above described.