and seemed to study its texture and thickness. Then he examined
the typed characters more closely with a little pocket magnifying
glass, his lips moving as if he were counting something. Next he
seized a mass of correspondence on his desk and began comparing
the letter with others, apparently to determine just the shade of
writing of the ribbon. Finally he gave it up and leaned back in
his chair regarding us.

"It is written in the regular pica type," he remarked
thoughtfully, "and on a machine that has seen considerable rough
usage, although it is not an old machine. It will take me a little
time to identify the make, but after I have done that, I think I
could identify the particular machine itself the moment I saw it.
You see, it is only a clue that would serve to fix it once you
found that machine. The point is, after all, to find it. But once
found, I am sure we shall be close to the source of the letter. I
may keep this and study it at my leisure?"

"Certainly."

For a moment Carton was silent. Then it seemed as though the
matter of Betty Blackwell brought to mind what he had read in the
morning papers.

"That robbery of Langhorne's safe was a most peculiar thing,
wasn't it?" he meditated. "I suppose you know what Miss Blackwell
was?"

"Langhorne's stenographer and secretary, of course," I replied
quickly.