In this one trick, four cards selected by four different persons are readily discovered by the performer, in the following manner:
Four cards are given to a member of the company, a second four to another person, and a third and fourth four to two others. You direct each of those holding these cards to choose one mentally, and to shuffle his packet of four containing it as much as he pleases.
For your own part, you must take care to remember each of the four persons according to the order in which you now take back the cards.
You receive one of the packets and hold it in the left hand, face upward. Bear in mind that the person from whom you take these cards is number one. You similarly take a second packet, which you lay face upward on the first in the left hand. The one from whom you receive these is to be remembered as number two. The procedure is the same for the remaining two packets, taken from the persons whom you designate to yourself as number three and number four respectively.
You next deal the cards from the left hand, laying each face upward on the table. In this distribution, you place the cards from left to right in a row of four, and repeat this operation until all are displayed on the table. There are thus four heaps, with four cards in each heap.
A brief reflection at this point will explain the manner of the trick. The four cards received from number one were the first four cards laid down. Therefore, the card selected by number one is the bottom card in one of the four heaps. Similarly, the four cards held by number two now make the second card in each of the heaps, and the card chosen by him is the socond card in one of those piles. The card selected by number three is likewise the third card in one of the piles, and the card of number four is the fourth.
After the cards have been thus laid out, you ask each of the four persons to indicate the particular pile containing his card. You can then instantly name the cards selected, because the card of number one is the first or bottom one in the pile he points out; the card of number two is the second card in the pile pointed out by him, and the cards of number three and number four are respectively the third and the fourth cards in the heaps indicated.
This trick, may be performed also for three persons, giving three cards to each, and afterward distributing them in three piles. Or it might be done, if not too much of a tax on the memory, for a larger number of persons up to seven, making in each case the number of cards given to each person correspond to the number of persons, and having a like number of separate piles in the final arrangement.