“Place your finger and thumb upon the left-hand bottom corner of this card, Charles,” said he. “Pass them lightly backwards and forwards, and tell me what you feel.”

“It has been pricked with a pin.”

“Precisely. What is the card?”

My uncle turned it over.

“It is the king of clubs.”

“Try the bottom corner of this one.”

“It is quite smooth.”

“And the card is?”

“The three of spades.”

“And this one?”