Anthony Cade’s false clue about the diamond

Anthony Cade’s false clue about the diamond is a deliberate decoy that converts evidence about a rose-shaped device into a convincing but incorrect library search. By directing suspicion toward a hidden cavity among the books, Cade gives Mademoiselle Brun a reason to act and creates an opportunity to catch her, while the real hiding place remains in the rose garden.

The Clues Behind the Decoy

Cade builds his explanation from several pieces of evidence rather than inventing an arbitrary hiding place. A cipher message had already produced a reference to Richmond and a sequence of numbers, but the investigators had tried and failed to solve it. In the late Count Stylptitch’s memoirs, Cade had read about a “flower” dinner at which the guests wore badges depicting flowers. The Count’s badge, he explained, was an exact duplicate of the curious device found in a cavity in the secret passage: it represented a rose.

The device’s markings suggested rows: buttons, the letter E, and knitting. Cade connected that repeated arrangement to books, which stand in rows, and added a title from Lord Caterham’s library catalogue, The Life of the Earl of Richmond. Together, Richmond, the numbers, the rose emblem, and the rows supplied the apparent logic of a bibliographic solution. The details were real, but Cade’s proposed destination was not.

The Library as a False Destination

Cade presented the inference as a reasonable solution: use the cipher’s numbers to locate shelves and books, then search for a dummy volume or a cavity behind a particular book. The proposal gave the assembled company something concrete to test and made the library appear to be the likely hiding place. Its persuasive force depended on the fit between the clues and the physical arrangement of books, not on the existence of the diamond there.

Cade later disclosed that the book theory was an invention intended to trap Mademoiselle Brun. He knew that she would be drawn toward the supposed hiding place and arranged for the false lead to reach her at the moment it could serve his plan. The decoy thus had two audiences: it offered the company an apparently ingenious answer, while its practical purpose was to prompt the culprit to move.

The Trap and Its Timing

Cade’s explanation of the scheme connects the library story to the night’s communications and searches. The false Lemoine was eager to pass news of the supposed discovery to an accomplice and also wanted to keep everyone in the room. He told Tredwell to deliver a note at once; Tredwell carried it upstairs to the schoolroom, where it was intended for Mademoiselle Brun. The false Lemoine then accused Cade of being King Victor, creating a diversion that prevented the others from leaving the room.

The accusation bought time for the accomplice to act on the supposed location. By the time the company went to the library to look for the stone, the false Lemoine believed the diamond would already have been removed. Cade’s false clue therefore functioned not just as a wrong answer but as part of a timed contest: it helped bring Mademoiselle Brun into the sequence of action while the others were held in place by a staged accusation.

The Real Hiding Place and the Decoy’s Meaning

The actual solution led away from the library. Cade said that on Monday afternoon he had recognized the rose device for what it originally represented and gone straight to the rose garden; Mr Fish had independently reached the same idea. The search instructions used fixed landmarks and counts: with one’s back to the sundial, take seven paces forward, eight to the left, and three to the right, toward bushes of bright red roses called Richmond. The diamond was not concealed in a book or a wall cavity; the proposed next step was to dig among the bushes.

Cade later made clear that the library theory had been designed to expose the woman who would pursue it. He and Mr Fish watched for the right moment, with Fish keeping watch on the terrace and whistling when it arrived. At the Dover house, they also imposed martial law to prevent the Comrades from communicating with the false Lemoine; once word reached him that the Comrades had left, he proceeded with his plan to denounce Cade. The book search was therefore one part of a wider arrangement of surveillance, restricted communication, and controlled misinformation.

The decoy’s irony lies in how faithfully it borrows the shape of a genuine deduction. The rose, Richmond reference, numbers, and rows all matter, but Cade redirects their apparent meaning toward books so that an adversary will reveal herself. The false solution turns interpretation into action: a clue is useful not only for finding an object, but for predicting who will respond to it and when. The diamond’s garden hiding place and the invented library destination mark the difference between solving the puzzle and using the puzzle to set a trap.