sy in answer to his letter. That would account for his addressing me
in Russian through the key-hole; and, of course, an official from the
Russian Embassy would be the very last person in the world whom he would
like to observe any indications of his little etching experiments. But,
anyhow, be that as it may," Hewitt concluded, "your drawings are safe now,
and if once Mirsky is caught, and I think it likely, for a man in his
shirt-sleeves, with scarcely any start, and, perhaps, no money about him,
hasn't a great chance to get away--if he is caught, I say, he will
probably get something handsome at St. Petersburg in the way of
imprisonment, or Siberia, or what not; so that you will be amply avenged."

"Yes, but I don't at all understand this business of the drawings even
now. How in the world were they taken out of the place, and how in the
world did you find it out?"

"Nothing could be simpler; and yet the plan was rather ingenious. I'll
tell you exactly how the thing revealed itself to me. From your original
description of the case many people would consider that an impossibility
had been performed. Nobody had gone out and nobody had come in, and yet
the drawings had been taken away. But an impossibility is an
impossibility, after all, and as drawings don't run away of themselves,
plainly somebody had taken them, unaccountable as it might seem. Now, as
they were in your inner office, the only people who could have got at them
besides yourself were your assistants, so that it was pretty clear that
one of them, at least, had something to do with the business. You told me
that Worsfold was an excellent and intelligent draughtsman. Well, if such
a man as that meditated treachery, he would probably be able to carry away
the design in his head--at any rate, a little at a time--and would be
under no necessity to run the risk of stealing a set of the drawings. But
Ritter, you remarked, was an inferior sort of man. 'Not particularly
smart,' I think, were your words--only a mechanical sort of tracer. _He_
would be unlikely to be able to carry in his head the complicated details
of such designs as yours, and, being in a subordinate position, and
continually overlooked, he would find it impossible to make copies of the
plans in the office. So that, to begin with, I thought I saw the most
probable path to start on.

"When I looked round the rooms, I pushed open the glass door of the
barrier and left the door to the inner office aj