TO TELL THE SPOTS ON SELECTED CARDS.
Having presented the pack, that the person may choose several succeeding cards at pleasure, privately observe the card which is above those he has chosen, and how many he has drawn from the pack; it will then be easy to count how many spots they ought to contain.
For example, if the observed card be a nine, and four cards have been drawn, it may readily be seen that those drawn must be a knave, equivalent to 10 spots: a six, a four, and a two. You may then announce, that the cards in the person’s hand contain 22 spots.