"Problems seem to be in the air," Isa Benstein murmured. "Your flattering interest is very soothing to my vanity. You know what a conjurer means when he speaks of forcing a card on a spectator? Of course you do. The expert with his quickness and his patter can make the spectator he selects draw any card he chooses. The conjurer in this case chose me to force his card upon. But all the same when I came here I had no notion that I was wearing anything half so historic as the Blue Stone of Ghan."

"But you tound it out after you got here?" Frobisher said keenly.

"Yes. That was a piece of good luck. And when I did so I removed it. That was a piece of caution."

"Then you had worked it all out in your mind, I suppose?"

"Yes. I worked it out in the best possible way—backwards. I worked it out so completely that I was in a position to read another person's mind. Shall I read that other person's mind?"

Frobisher bowed and smiled in one of his quick grins. Lefroy shifted uneasily in his chair. Isa Benstein's lips were parted, her arms played idly by the side of her chair, there was no sign of fear in her eyes. When she spoke again it was quite calmly and slowly.

"We will begin with the conjurer," she said. "After all, he has succeeded in forcing the card that is destined to lead up to the brilliant trick that dazzles and astonishes everybody. We will assume, for the sake of argument, that you are the conjurer and I am the silly heedless spectator who is marked out as the involuntary accomplice."

"The mind could not grasp you in that senile capacity," Frobisher murmured.

"Then give your vivid imagination free run for once, Sir Clement. The card in this case represents something that you very much desired, call it the Blue Stone of Ghan. The sacred jewel is hidden in a certain place. Your great idea is to conjure that somewhere else, and being a master of your trade, you have to make use of a third party who shall make the transfer for you without knowing anything of the matter. Only a prince among conjurers could hope to bring off so brilliant a coup as that, but there is no great success without great audacity. But Count Lefroy is looking at his watch. I am afraid that he is not interested."

"It matters nothing about Lefroy," Frobisher said. "I am deeply interested. Pray go on."