lty conscience. Knowing himself to be a traitor, he may have
read the accusation in the other's eyes."

"The other being, I presume, Professor Moriarty."

"No less! When any of that party talk about 'He' you know whom they
mean. There is one predominant 'He' for all of them."

"But what can he do?"

"Hum! That's a large question. When you have one of the first brains of
Europe up against you, and all the powers of darkness at his back, there
are infinite possibilities. Anyhow, Friend Porlock is evidently scared
out of his senses--kindly compare the writing in the note to that upon
its envelope; which was done, he tells us, before this ill-omened visit.
The one is clear and firm. The other hardly legible."

"Why did he write at all? Why did he not simply drop it?"

"Because he feared I would make some inquiry after him in that case, and
possibly bring trouble on him."

"No doubt," said I. "Of course." I had picked up the original cipher
message and was bending my brows over it. "It's pretty maddening to
think that an important secret may lie here on this slip of paper, and
that it is beyond human power to penetrate it."

Sherlock Holmes had pushed away his untasted breakfast and lit the
unsavoury pipe which was the companion of his deepest meditations. "I
wonder!" said he, leaning back and staring at the ceiling. "Perhaps
there are points which have escaped your Machiavellian intellect. Let us
consider the problem in the light of pure reason. This man's reference
is to a book. That is our point of departure."

"A somewhat vague one."

"Let us see then if we can narrow it down. As I focus my mind upon it,
it seems rather less impenetrable. What indications have we as to this
book?"

"None."

"Well, well, it is surely not quite so bad as that. The cipher message
begins with a large 534, does it not? We may take it as a working
hypothesis that 534 is the particular page to which the cipher refers.
So our book has already become a LARGE book, which is surely something
gained. What other indications have we as to the nature of this large
book? The next sign is C2. What do you make of that, Watson?"

"Chapter the second, no doubt."

"Hardly that, Watson. You will, I am sure, agree with me that if the
page be given, the number of the chapter is immaterial. Also that if
page 534 finds us only in the second chapter, the length of the first
one must have been really intolerable."

"Column!" I cried.

"Brillian