Conjuring Credits

The Origins of Wonder

User Tools

Site Tools

Key Card

This principle is explained by Girolamo Cardano in his De subtilitate (1550, early in Book XV), and has been a staple of card magic ever since. See John M. Forrester's English translation of De subtilitate, Vol. 2, p. 754. Forrester mistranslates playing cards as pieces of paper, but the rest of his translation for this entry is clear enough.