“As far as we know, she was quite alone during that half-hour. Nobody entered or left that boudoir. What then occasioned this sudden change of sentiment?
“One can only guess, but I believe my guess to be correct. Mrs. Inglethorp had no stamps in her desk. We know this, because later she asked Dorcas to bring her some. Now in the opposite corner of the room stood her husband’s desk—locked. She was anxious to find some stamps, and, according to my theory, she tried her own keys in the desk. That one of them fitted I know. She therefore opened the desk, and in searching for the stamps she came across something else—that slip of paper which Dorcas saw in her hand, and which assuredly was never meant for Mrs. Inglethorp’s eyes. On the other hand, Mrs. Cavendish believed that the slip of paper to which her mother-in-law clung so tenaciously was a written proof of her own husband’s infidelity. She demanded it from Mrs. Inglethorp who assured her, quite truly, that it had nothing to do with that matter. Mrs. Cavendish did not believe her. She thought that Mrs. Inglethorp was shielding her stepson. Now Mrs. Cavendish is a very resolute woman, and, behind her mask of reserve, she was madly jealous of her husband. She determined to get hold of that paper at all costs, and in this resolution chance came to her aid. She happened to pick up the key of Mrs. Inglethorp’s despatch-case, which had been lost that morning. She knew that her mother-in-law invariably kept all important papers in this particular case.
“ Mrs. Cavendish, therefore, made her plans as only a woman driven desperate through jealousy could have done. Some time in the evening she unbolted the door leading into Mademoiselle Cynthia’s room. Possibly she applied oil to the hinges, for I found that it opened quite noiselessly when I tried it. She put off her project until the early hours of the morning as being safer, since the servants were accustomed to hearing her move about her room at that time. She dressed completely in her land kit, and made her way quietly through Mademoiselle Cynthia’s room into that of Mrs. Inglethorp.”