KNOCKING A CARD OUT OF THE PACK.
When a chosen card is replaced in the pack, bring it to the middle as you pretend to shuffle them.
The backs of the cards will be uppermost, so that no one can see where you have placed it.
Upon any one striking the cards you have merely to tighten your grip on the others and entirely release the centre one, for it to fall on the floor, where it will be discovered to be the selected card itself.