the first time in his life he felt distrustful
of himself, and he suspected, too, that Furneaux was only covering
abject failure by a display of high spirits.

"Why so pensive an attitude, James?" inquired the other softly. "Are
you still wondering what the extrados of a voussoir is?"

"I don't care a tuppenny damn what it is."

"But that's where you're wrong. That's where you're crass and
pig-headed. The extrados of a voussoir----"

"Oh, kill it, and let it die happy----"

"--is the outer curve of a wedge-shaped stone used for building an
arch. Now, mark you, those are words of merit. Wedge, arch--wedges of
fact which shall construct the arch of evidence. We'll have our man
in the dock across that bridge before we are much older."

"Confound it, how? He couldn't be in his bedroom and in the Quarry
Wood, four hundred yards away, at one and the same moment."

Furneaux gazed fixedly at his friend's forehead, presumably the seat
of reason.

"Sometimes, James, you make me gasp with an amazed admiration," he
cooed. "You do, really. You arrive at the same conclusion as I, a
thinker, without any semblance of thought process on your part. How do
you manage it! Is it through association with me? You know, there's
such a thing as inductive electricity. A current passing through a
highly charged wire can excite another wire, even a common iron one,
without actual contact."

"I've had a rotten afternoon, and don't feel up to your far-fetched
jokes just now; so if you have nothing to report, shut up," said the
Superintendent crossly.

"Then I'll cheer your melancholy with a bit of real news brightened
by imagination," answered Furneaux promptly. "Hilton Fenley couldn't
have fired the rifle himself, except by certain bizarre means which I
shall lay before the court later; but he planned and contrived the
murder, down to the smallest detail. He wore Brother Robert's boots
when available; from appearances Brother Robert is now wearing the
identical pair which made those footprints we saw, but I shall know
in the morning, for that fiery young sprig obligingly left another
well-marked set of prints in the same place twenty minutes ago. When
circumstances compelled Hilton to walk that way in his own boots, he
slipped on two roughly made moccasins, which he burned last night,
having no further use for them. Therefore, he knew the murder would
take place this morning.

"I've secured shreds of the sacking out of which he made