The audience is shown two slates each being blank on both sides. The slates are tied together with a rope or ribbon and given to a spectator to hold. A chalk is waived over the slates as the spirits are summoned. When the slates are untied they now contain some writing. This may be the name of a selected card or any other forced prediction.
With these Magnetic Slates the apparatus can be examined by the spectator without fear of detection.
Slates measure approximately 12 inches by 9 inches and have mahogany frames.