"I didn't mean it seriously, sir," the Sergeant said surprised. "It was just a silly joke, like you said."
"Perhaps it wasn't quite such a silly joke," Henmngway said. "Come to think of it, there is something queer about that book. Why did anyone want to burn it?"
"You said yourself, sir, you didn't blame anyone for getting rid of it, the way the old lady would keep on talking about it."
"You want to cure yourself of this ridiculous habit you've got into of remembering all the things I say which it would do you more good to forget," said Hemingway. "The only member of this outfit who might have pitched the book into the incinerator because he was tired of hearing about it is young Herriard, and he didn't do it."
"How do you know that, sir?"
"He said he didn't - that's how I know it."
"Seems to me you've only got his word for it," objected the Sergeant.
"Thanks," Hemingway said bitterly. "I may not be much good as a detective - in fact, I'm beginning to think I'm lousy - but every now and then I do know when a chap's lying and when he's speaking the truth. Stephen didn't burn that book, and it's no use trying to get me to believe that it was thrown into the incinerator by mistake, because that's a tale I never did believe, and never shall. Someone tried to get rid of that book, for some other reason than the one Stephen would have had, if he'd done it." His countenance suddenly assumed a rapt expression the Sergeant knew well. He shot out a finger. "Now, Joseph doesn't want the old lady to get hold of another copy, which is why his loving nephew Stephen's out to help her to do so. My lad, I believe we're on to something!"
"You may be, sir, but I'm damned if I am!" said the Sergeant. "I mean, what can a book about some Empress or other have to do with Nathaniel Herriard's death? It doesn't make sense!"
"Look here!" Hemingway said. "Who was this Empress?"