Fullaway made an inarticulate growling protest, but Miss Slade took no notice and continued in even, dispassionate tones, as if she had been explained a mathematical problem.

“The affair prospered.  The Princess came.  The reward of fifty thousand pounds was offered.  Then Mr. Rayner and I put our heads together more seriously.  Much, of course, depended upon me, as I was on the spot.  I wanted a chance to get into Van Koon’s rooms, some time when he was out.  Fortunately the chance came.  One afternoon, when Van Koon was in our office, he and Mr. Fullaway settled to dine out together and go to the theatre afterwards.  That gave me my opportunity.  I made an excuse about staying late at Mr. Fullaway’s office and when both men were clear away I let myself into Van Koon’s room—­I’d already made preparations for that—­and proceeded to search.  I found the parcel.  It was a small, square parcel, done up in brown paper and sealed with black wax; it had been opened, the original wrapper put on again, and the seals resealed.  I took it into Mr. Fullaway’s rooms and opened it, carefully.  Inside I found a small cigar-box, and in it the Princess’s jewels.  I took them out.  Then I put certain articles of corresponding weight into the box, did it up again precisely as I had found it, smeared over the seals with more black wax, went back to Van Koon’s room with it, and placed it again where I had found it—­in a small suit-case.

“I now knew, of course, that Mr. James Allerdyke had sent those jewels direct to Mr. Fullaway, immediately on his arrival in Hull, and that they had fallen by sheer accident into Van Koon’s hands.  But I wanted to know more.  I wanted to know if Van Koon had any connection with this affair, and if, when he saw that the parcel was from Hull, he had immediately jumped to the conclusion that it might be from James Allerdyke, and might contain the actual valuables.  Fortunately, Mr. Rayner had already made arrangements with a noted private inquiry agent to have Van Koon most carefully and closely watched.  And the very day after I found and took possession of the jewels we received a report from this agent that Van Koon was in the habit of visiting the shop and manufactory of a German chemist named Schmall, in Whitechapel.  Further, he had twice come away from it, after lengthy visits, in company with a man whom the agent’s employees had tracked to the Hotel Cecil, and whom I knew, from their description, to be Mr. Merrifield, Mr. Delkin’s private secretary.

“Naturally, having discovered this, we gave instructions for a keener watch than ever to be kept on both these men.  But the name of the German chemist gave me personally a new and most important clue.  There had been employed at the Waldorf Hotel, for some weeks up to the end of the first week in May, a German-Swiss young man, who then called himself Ebers.  He acted as valet to several residents; amongst others, Mr. Fullaway.  He was often in