You now take a set in each hand, presenting them to the two persons, requesting them to replace the drawn cards. You must pretend to present to each person the set from which he drew his card, but in reality you present the red set to the person who drew the black card, and the black set to the person who drew the red card.
Each person having replaced his card, you get each set shuffled. Then you take them in hand, and by running them over you easily find the red card amongst the black, and the black card amongst the red.
Of course you will have prepared the sets beforehand, and take care to alter the arrangement as soon as possible after the trick. But you can prepare the pack in the presence of others without their detecting it. Distribute the cards by dealing according to the two colours; take them up, and having placed the red set a little projecting over the black, set them down, and, pretending to cut them, separate the sets.
6. Twenty cards being arranged upon a table, a person thinks of two, and you undertake to guess them.
Lay out twenty cards of any kind, two by two,
| c | i | c | o | s |
| d | e | d | i | t |
| t | u | m | u | s |
| n | e | m | o | n |
and request a party to think of two in a line; that is, one of the ten sets formed by the twenty cards. This done you take up the sets in the order in which they lie, and place them in rows according to the letters of the words. You may use a diagram like the preceding, but as the words are easily retained it had better be dispensed with, distributing the cards on the table just as though upon the diagram, which will make the trick more puzzling and extraordinary. Proceed as follows:—Place the cards two by two on similar letters: thus, place the two cards of the first set on the two d's in dedit; the two cards of the second set on the two i's of cicos and dedit; the two of the third set on the two c's, and so on with the ten sets.
All the letters of the words being thus covered, ask the party who has thought of the cards to tell you in which lines these cards are. If both are in the first line (cicos), they must be those on the two c's; if they are both in the second line, they cover the d's in dedit; both in the third line, they cover the u's in tumus; both in the fourth, they cover the n's in nemon.
If one be in the first line and the other in the second, they cover the i's in cicos and dedit, and thus of the rest—the two cards thought of NECESSARILY covering two SIMILAR LETTERS, whilst each of the letters occurs only TWICE in the diagram.
7. To tell a card thought of without even looking at the cards.