An illustration of the use of the same device in a somewhat different form will be found in the item next described, and in the trick entitled “Where is it?” post. Other ways of using it will suggest themselves to any reader of an inventive turn.
[4] Better still, thicken the under edge by the interposition between card and velvet of a slip of white card, as described in The Detective Die, post.
THE DETECTIVE DIE
This is another of the new departures dependent upon the use of the velvet mat. Broadly stated, the effect of the trick is as follows.
One of a group of six different cards laid out in a row or rows repeatedly changes place with some other, the position which it occupies, or to which it has moved, being indicated by the cast of an ordinary die. This may be repeated any number of times.[5]
The requirements for the trick are as follows:
1. The Velvet Mat. This should be one with a plain surface, dimensions preferably eighteen inches by ten, so as to admit of the six cards being laid in one row. A smaller size, say twelve by nine, may suffice, the six cards in this case being arranged in two rows. In either case there must be a space of an inch or so between each pair.
2. Six cards of like denomination (say for the purpose of illustration six queens of diamonds), each backed with black velvet and blackened at the edges all around save at one end. Here the card is thickened by the interposition of a slip of white cardboard between itself and the velvet, so that the card as viewed from that end shall show a clearly visible white edge. Each card has all four of its corners snipped off to a microscopic extent, say a sixteenth, or less, of an inch.
3. An ordinary pack of cards one of which (in the case supposed, the queen of diamonds) bears a mark upon its back recognisable by the performer, but not conspicuous enough to be noticed by any one else.