at Scotland Yard
after the arrival of the foreign mails.

That day he had made a particularly good haul from the
waste-paper-baskets, for his "catch" included several comparatively good
specimens from Japan and Fiji. He sat gloating over these treasures,
examining them carefully and holding each one up to the light as he
separated it from the piece of paper to which it had been affixed. He
pasted them one by one in his stamp album with loving, lingering fingers,
adjusting each stamp in its little square in the book with meticulous
care. He was so absorbed in this occupation that he did not hear the
ascending footsteps drawing nearer to his door, and did not see a visitor
at the door when the footsteps ceased. It was Crewe's voice that recalled
him back from the stamp collector's imaginary world.

"Why, Mr. Crewe," said Rolfe, with evident pleasure, "who'd have thought
of seeing you?"

"Your landlady asked me if I'd come up myself," said Crewe, in explaining
his intrusion. "She's 'too much worried and put about, to say nothing of
having a bad back,' to show me upstairs."

"I've never known her to be well," said Rolfe, with a laugh. "Every
morning when she brings up my breakfast I've got to hear details of her
bad back which should be kept for the confidential ear of the doctor. But
she regards me as a son, I think--I've been here so long. But now you are
here, Mr. Crewe--" Rolfe waited in polite expectation that his visitor
would disclose the object of his visit.

But Crewe seemed in no hurry to do so. He produced his cigar case and
offered Rolfe a cigar, which the latter accepted with a pleasant
recollection of the excellent flavour of the cigars the private detective
kept. When each of them had his cigar well alight, Crewe glanced at the
open stamp album and commenced talking about stamps. It was a subject
which Rolfe was always willing to discuss. Crewe declared that he was an
ignorant outsider as far as stamps were concerned, but he professed to
have a respectful admiration for those who immersed themselves in such a
fascinating subject. Rolfe, with the fervid egoism of the collector,
talked about stamps for half an hour without recalling that his visitor
must have come to talk about something else.

"I've got a small stamp collection in my office," said Crewe, when Rolfe
paused for a moment. "It belonged to that Jewish diamond merchant who was
shot in Hatton Gardens two years ago. You remember his case?"

"