Rising, she left me. When she returned she was carrying a work-bag of blue brocaded silk, which she placed upon her lap as she reseated herself. In her hand also she had an evening paper which she handed to me with a casual remark that I might like to look at it while she got her work ready. I knew well enough that this was for the benefit of the other people in the room, who, as usual, were keenly interested in any friends of a pretty woman, and were scrutinising me pretty carefully. I knew, too, that Gabrielle had some further motive in her mind. Accordingly, I leaned back in my chair and read the paper diligently. A moment later I noticed Madame Gabrielle telegraphing me in our "finger Morse." "Look carefully at the book showing in the mouth of my work-bag," she signalled, "and get a copy at once. It belongs to Heinrich, and I have just borrowed it from his room. He may be back at any moment--he has only just gone out--and I must replace it at once." She had casually left the mouth of her work-bag open. It revealed the title-page of an open book, published, as I saw, about seven years before. The title was _Royal Love Letters_. I had never heard of the volume, but I made a note of its title. Madame Gabrielle, with an excuse, quitted the room for a few moments, taking the book with her in her bag. On her return she began talking pleasantly about general subjects, but she was listening keenly, I could see. Soon we heard the front door slam, and a heavy shuffling tread crossed the hall and went up the stairs. "Blind Heinrich," she telegraphed; "I was only just in time. He is terribly watchful, and would certainly have noticed if the book had not been on the table where he left it. I often wonder whether he is as blind as he pretends to be. You had better go; if he comes in here for tea, it is quite possible he may recognise you." A quarter of an hour later we were walking along Westbourne Grove together, and Gabrielle told me the history of the mysterious book. For several days, she said, she had been following Heinrich, who had suddenly developed an amazing interest in second-hand bookstalls. He had gone into shop after shop in various parts of London, asked a single question apparently, and come out again. At length she had managed to overhear him ask at one shop for a copy of _Royal Love Letters_. The shopkeeper had not the volume in stock, and, as the request was such a peculiar one for a man of Heinrich's temperament, Madame Gabrielle determined to run risks and follow him daily. He entered six more shops, making the same request at each, and at length, in a dingy little by-lane in Soho, managed, to his evident glee, to get what he wanted, and carried it back to Hereford Road with obvious satisfaction. "Why that particular book, and why so much trouble to get it?" said Madame Gabrielle. "What do you make of it, Mr Sant?"