I'd sooner trust Urquhart than Mackenzie, and if the
case lies against Urquhart--"

"It will assuredly break him," I put in, "unless he can prove the
charge, or that he was honestly mistaken."

"Then, sir," said the Captain, "I'll have to show you this. It's ugly,
but it's only justice."

He pulled a sovereign from his pocket and pushed it on the
writing-table under my nose.

"What does this mean?"

"It is a marked one," said he.

"So I perceive." I had picked up the coin and was examining it.

"I found it just now," he continued, "in the room below. The upsetting
of the table had scattered Mackenzie's stakes about the floor."

"You seem to have a pretty notion of evidence," I observed sharply.
"I don't know what accusation this coin may carry; but why need it be
Mackenzie's? He might have won it from Urquhart."

"I thought of that," was the answer. "But no money had changed hands.
I enquired. The quarrel arose over the second deal, and as a matter of
fact Urquhart had laid no money on the table, but made a pencil-note
of a few shillings he lost by the first hand. You may remember, sir,
how the table stood when you entered."

I reflected. "Yes, my recollection bears you out. Do I gather that you
have confronted Mackenzie with this?"

"No. I found it and slipped it quietly into my pocket. I thought we
had trouble enough on hand for the moment."

"Who marked this coin?"

"Young Fraser, sir, in my presence. He has been losing small sums, he
declares, by pilfering. We suspected one of the orderlies."

"In this connection you had no suspicion of Mr. Mackenzie?"

"None, sr." He considered for a moment, and added: "There was a
curious thing happened three weeks ago over my watch. It found its
way one night to Mr. Mackenzie's quarters. He brought it to me in the
morning; said it was lying, when he awoke, on the table beside his
bed. He seemed utterly puzzled. He had been to one or two already to
discover the owner. We joked him about it, the more by token that his
own watch had broken down the day before and was away at the mender's.
The whole thing was queer, and has not been explained. Of course in
that instance he was innocent: everything proves it. It just occurred
to me as worth mentioning, because in both instances the lad may have
been the victim of a trick."

"I am glad you did so," I said; "though just now it does not throw any
light that I can see." I rose and paced the room. "Mr. Mackenzie had
be