"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
better be confronted with this, too, and hear your evidence. It's best
he should know the worst against him; and if he be guilty it may move
him to confession."

"Certainly, sir," Captain Murray assented. "Shall I fetch him?"

"No, remain where you are," I said; "I will go for him myself."