* * * *

"You see, Watson," he explained, in the early hours of the morning, as
we sat over a glass of whisky and soda in Baker Street, "it was
perfectly obvious from the first that the only possible object of
this rather fantastic business of the advertisement of the League, and
the copying of the 'Encyclopaedia,' must be to get this not over bright
pawnbroker out of the way for a number of hours every day. It was a
curious way of managing it, but really, it would be difficult to
suggest a better. The method was no doubt suggested to Clay's
ingenious mind by the color of his accomplice's hair. The L4 a week
was a lure which must draw him,--and what was it to them, who were
playing for thousands? They put in the advertisement, one rogue has
the temporary office, the other rogue incites the man to apply for it,
and together they manage to secure his absence every morning in the
week. From the time that I heard of the assistant having come for half
wages, it was obvious to me that he had some strong motive for
securing the situation."

"But how could you guess what the motive was?"

"Had there been women in the house, I should have suspected a mere
vulgar intrigue. That however was out of the question. The man's
business was a small one, and there was nothing in his house which
could account for such elaborate preparations and such an expenditure
as they were at. It must then be something out of the house. What
could it be? I thought of the assistant's fondness for photography,
and his trick of vanishing into the cellar. The cellar! There was the
end of this tangled clue. Then I made inquiries as to this mysterious
assistant, and found that I had to deal with one of the coolest and
most daring criminals in London. He was doing something in the
cellar--something which took many hours a day for months on end. What
could it be, once more? I could think of nothing save that he was
running a tunnel to some other building.

"So, far I had got when we went to visit the scene of action. I
surprised you by beating upon the pavement with my stick. I was
ascertaining whether the cellar stretched out in front or behind. It
was not in front. Then I rang the bell, and as I hoped, the assistant
answered it. We have had some skirmishes, but we had never set eyes
upon each other before. I hardly looked at his face. His knees were
what I wished to see. You must yourself have remarked how worn,
wrinkled, and staine