d now I saw that
while one had laid his hand on the stranger's shoulder the other had
taken him by the opposite arm. "Why," said the former, looking into his
face, "it's Broady Sims!"

"All right," the man growled resignedly. "It's a cop. I'll go quiet."

But as he spoke I saw the free hand steal out behind him and pitch away
a crumpled fragment of paper. One of the policemen saw it too, followed
it with his eyes, and saw me snatch it up.

"That's right, sir," he said, "take care of that; and we'll have a cab,
in case anything else drops accidentally. It's just a turning over,
Broady, that's what it is."

I spread out the piece of paper, and was astonished to find inscribed on
it just such another series of figures, in groups of eight, as was found
in the cypher message in the Case of the Lever Key.

Here was a great find--a secret message as clear to me as to Mayes
himself, and as likely as not the scrap of paper that would hang him! I
took one of the plain-clothes men aside while the other kept his hold of
Broady Sims.

"This is very important," I said. "It is a cypher message which Mr.
Hewitt can read--or I, myself, in fact, with a little time. Must you
take it with you? If so, I'll make a copy now."

"Well, sir, we're responsible, you see," the man said, "so I think we
must take it; so perhaps you'd better make a copy, as you suggest."

"Very well," I said, "that is done in a few seconds. You can take your
man off, and I will go direct to Mr. Hewitt and Inspector Plummer with
the copy." And with that I made the copy, which read thus:--

23, 19, 15, 1, 9, 14, 9, 2; 20, 8, 1,
20, 14, 14, 20, 8; 14, 5, 12, 4, 9, 7,
5, 14; 3, 8, 18, 23, 0, 14, 1, 8; 22,
9, 6, 1, 18, 3, 5, 1; 19, 14, 15, 21,
9, 0, 20, 12; 18, 12, 21, 1, 6, 23, 20,
12; 9, 18, 15, 5, 18, 13, 12, 20.

It struck me to ask the manager if the cheque just presented were one of
those procured from Mr. Trenaman the night before, and I found that it
was. Then I left the policemen with their prisoner and made for the
nearest cab-rank. This cypher message, no doubt conveying Mayes's
instructions to the man just captured, was probably of the utmost
importance, and Hewitt must see it at once; and as the cab ambled along
towards Barbican I busied myself in deciphering the figures according to
the plan of the knight's move in chess, as Hewitt had explained to me. I
cou