Operations carried out successfully, but S. double crossed us. Has removed stone from hiding-place. Not in his room. I have searched. Found following memorandum which I think refers to it: “ Richmond Seven Straight Eight Left Three Right. ”

“ S. ?” said Anthony. “Stylptitch, of course. Cunning old dog. He changed the hiding-place.”

“Richmond,” said Virginia thoughtfully. “Is the diamond concealed somewhere at Richmond, I wonder?”

“It’s a favourite spot for royalties,” agreed Anthony.

Battle shook his head.

“I still think it’s a reference to something in this house.”

“I know,” cried Virginia suddenly.