Sherlock Holmes sat up with a whistle. "By Jove, Peterson!" said
he, "this is treasure trove indeed. I suppose you know what you
have got?"
"A diamond, sir? A precious stone. It cuts into glass as though
it were putty."
"It's more than a precious stone. It is the precious stone."
"Not the Countess of Morcar's blue carbuncle!" I ejaculated.
"Precisely so. I ought to know its size and shape, seeing that I
have read the advertisement about it in The Times every day lately.
It is absolutely unique, and its value can only be conjectured, but
the reward offered of 1000 pounds is certainly not within a
twentieth part of the market price."
"A thousand pounds! Great Lord of mercy!" The commissionaire
plumped down into a chair and stared from one to the other of
us.
"That is the rewar
