"Just let me look at that typewritten letter again, will you?" asked Mr. Carless. "It seems impossible, but we might get something out of that."
Mr. Cave handed the letter over, and once more it was passed from hand to hand: finally it fell into the hands of Miss Penkridge, who began to examine it with obvious curiosity.
"Afraid there's nothing to be got out of that!" sighed Mr. Carless. "The rogues were cunning enough to typewrite the message—if there'd been any handwriting, now, we might have had a chance! You say there was nothing on the envelope but your name, Mr. Cave?"
Mr. Cave opened his pocketbook again.
"There is the envelope," he said. "Nothing but Mr. Cave, as you see—that is also typewritten."
Miss Penkridge picked up the envelope as Mr. Cave tossed it across the table. She appeared to examine it carefully, but suddenly she turned to Mr. Carless.
"There is a clue in these things!" she exclaimed. "A plain clue! One that's plain enough to me, anyway. I could follow it up. I don't know whether you gentlemen can."
Mr. Carless, who had, up to that point, treated Miss Penkridge with good-humoured condescension, turned sharply upon her.
"What do you mean, ma'am?" he asked. "You really see something in—in a typewritten letter?"
"A great deal!" answered Miss Penkridge. "And in the stationery on which it's typed, and in the envelope in which it's inclosed. Now look here: This letter has been typed on a half-sheet of note-
