By his own mental powers the magician is able to influence several people to call out numbers which when added will produce his predicted total. The slate measures 8" x 10" having a black silk velvet covering attached which conceals the prediction with total until the revelation is made. Remember 3 different people each with a four digit number of their choosing yet you are able to correctly predict the total.

Two pages of instructions accompany this very special slate from Thayer Magic Manufacturing Company. Circa 1930's. Hardwood frame with black silk velvet attachment also includes early chalk box with couple of pieces and a cloth carry bag. Condition very fine.