Watch Wizardry

Effect: You use a watch to divine a thought-of-number.

Secret: Show a watch and ask someone to think of any number from 1 to 12. Tap a pencil against numbers on the dial. As you do this, the spectator mentally counts to 20, one for each tap, beginning with one above the number he is thinking of. You make the first seven taps anywhere on the watch face. On the eighth, tap your pencil on 12. Continue tapping the numbers anti-clockwise around the dial. When the spectator reaches 20, your pencil will be pointing to the number he is thinking of.