“Mr. Praye is in Paris. He has been there some days,” was the staggering reply. “You’ve found a mare’s nest. Really there is no mystery at all about anything that has happened to this young lady in my house. What reason in the world was there for me to engage her, except my desire to find a comfortable job for a very very nice girl?” And then: “Is Braime better?” “Sergeant Braime is much better,” said Michael, and saw that he had got beneath her guard. She cringed back as at a blow, and her voice had lost a little of its assurance when she faltered: “Sergeant Braime? I am talking about my butler----” “And I’m talking about Sergeant Braime of the Criminal Investigation Department, who has been in your service for six months.” Her mouth was an O of amazement. “But--but he was recommended to me by----” “By a spurious Prisoners’ Aid Society,” said Michael. “The idea was that, if you believed that the man had a criminal record, he had a better chance of coming into your ladyship’s service.” She had recovered herself in an instant. “But why?” she drawled. “Why put a detective in my household? It is an abominable outrage and I shall report the matter to the Commissioner of Police immediately.” He was looking round the room and his eyes rested upon that section of the bookshelves which was protected by the wire-covered door. “You have a book there that I should like to see. I intended coming last night, only something prevented me.” “A book?” “A book called _The Life of Washington_--sounds a fairly innocuous title, doesn’t it?” She walked to the bookcase, and, taking a key from the drawer of her desk, opened the wire net cover. “There it is,” she said. “Read it and be improved.” She turned to walk to the door and stood there watching him. And then he did the last thing she expected. From his pocket he took a thick red glove and drew it on his right hand. Reaching up, he seized the back of the book and jerked it loose. There was a click, a spark of blinding white light, but nothing else happened, and he laid the book with some difficulty on the table. “A very good imitation,” he said quietly, “but it is less of a book than a steel box, and any person who attempts to pull it out automatically makes contact with a very powerful electric current. Where is the switch?” She did not reply. Her face, under the powder, was drawn and haggard. Walking to the door, Michael searched for a while, then, stooping down, he turned over a big switch that was well concealed by a hanging portière. “Have you the key of this box?” “It is not locked,” she said, and, coming to his side, pressed a spring. The lid sprang open. The “book” was, as he surmised, hollow. It was also empty. “Is there a law against having a safe-box made like a book?” she asked, and her voice was almost sweet. “Does one get into _very_ serious trouble for protecting one’s property from thieving butlers and--inquisitive amateur detectives?”