The performer lays upon the table ten cards, side by side, face downwards. Anyone is then at liberty (the performer meanwhile retiring from the room) to shift any number of the cards (from one to nine inclusive) from the right hand end of the row to the left, but retaining the order of the cards so shifted. The performer, on his return, makes a little speech: “Ladies and gentlemen, you have shifted a certain number of these cards. Now, I don’t intend to ask you a single question. By a simple mental calculation I can ascertain the number you have moved, and by my clairvoyant faculty, though the cards are face downwards, I shall pick out one corresponding with that number. Let me see” (pretends to calculate, and presently turns up a card representing “five”). “You shifted five cards and I have turned up a five, the exact number.” The cards moved are not replaced, but the performer again retires, and a second person is invited to move a few more from right to left. Again the performer on his return takes up the correct card indicating the number shifted. The trick, unlike most others, may be repeated without fear of detection. [Illustration] The principle is arithmetical. To begin with, the cards are arranged, unknown to the spectators, in the following order: Ten, nine, eight, seven, six, five, four, three, two, one. Such being the case, it will be found that, however many are shifted from right to left, the _first_ card of the new row will indicate their number. Thus, suppose _three_ are shifted. The new order of the cards will then be: _Three_, two, one, ten, nine, eight, seven, six, five, four. So far, the trick is easy enough, but the method of its continuance is a trifle more complicated. To tell the position of the indicating card after the second removal, the performer privately adds the number of that last turned up (in this case _three_) to its place in the row--_one_. That gives us _four_, the card to be turned up after the next shift will be the fourth. Thus, suppose six cards are now shifted, their new order will be: Nine, eight, seven, _six_, five, four, three, two, one, ten. Had five cards only been shifted, the _five_ would have been fourth in the row, and so on. The performer now adds _six_, the number of the card, to its place in the row, _four_: the total, _ten_, gives him the position of the indicator for the next attempt. Thus, suppose four cards are next shifted, the new order will be: Three, two, one, ten, nine, eight, seven, six, five, _four_. The next calculation, 4 and 10, gives us a total 14. The ten is, in this case, cancelled, and the fourteen regarded as _four_, which will be found to be the correct indicator for the next shifting.