of man I wanted.
I was rewarded when we were pulled out to the _Fiona_ by those
two men of Fuller's. One of them was red-headed, you remember? Well,
that man was left-handed. It was very easy to observe that by the way
he held his oar and generally handled things. Of course I was very
bucked about it, so I paid very close attention to him. He wore a
wedding-ring--ergo, he was married. It is not conclusive, of course,
but a fairly safe guess when you're playing at toy detectives. So when
I found the knife I looked for some sign that it belonged to him, and
found it. It was all quite simple."

"I daresay it will be when you explain it, but you haven't in the
least explained it yet," I pointed out. "How about the schoolmaster
and all that, and what made you think the knife belonged to him."

"Simply because he was very probably--working on the law of
averages--the only left-handed man among the crew, and that knife
belonged to a left-handed man."

"But my dear old fellow," I cried, "you don't seriously mean to tell
me that you can say whether a man is left-handed or not by looking at
marks on the handle of his knife?"

"Not on the handle," Dennis explained; "on the blade. Have you got a
knife on you?"

I produced my pen-knife.

"I'll trust you with it," I declared confidently. "I've never held any
secrets from you, Den."

Dennis opened the knife and laid it in the palm of his hand. I stood
still and watched him.

"You've sharpened pencils with this knife and the pencils have left
their mark. If you hold the knife as you would when sharpening a
pencil and look down on the blade there are no pencil marks visible.
Now turn the knife over and you will find the marks on the other side
of the blade."

"Half a minute," I said eagerly, "let's have a look. The knife is in
position for sharpening a pencil and the back of the knife is pointing
to my chest. The marks are underneath." I took a pencil from my pocket
and tried it. "Yes, I've got you, Dennis. It's quite clear. If I held
the knife with the point to my right instead of to my left, as I
should do in sharpening with my left hand, the marks appear on the
other side of the blade. It is not quite conclusive, Den, but it's
jolly cute."

"Not when you're looking for it," he said. "I was struck by the fact
that the knife which, by its size and weight, was a seaman's handy
tool, had also been used for the repeated sharpening of a blue pencil.
When I saw those indicati