"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 the pads to cover his feet; and an under gardener remembers seeing Mr. Hilton making off with an empty potato sack one day last week, and wondering why he wanted it. During some mornings recently Hilton Fenley breakfasted early and went out, but invariably had an excuse for not accompanying his father to the City. He was then studying the details of the crime, making sure that an expert, armed with a modern rifle, could not possibly miss such a target as a man standing outside a doorway, and elevated above the ground level by some five feet or more.
"No servant could possibly observe that Mr. Hilton was wearing Mr. Robert's boots, because they do not differ greatly in size; but luckily for us, a criminal always commits an error of some sort, and Hilton blundered badly when he made those careful imprints of his brother's feet, as the weather has been fine recently, and the only mud in this locality lies in that hollow of the Quarry Wood. It happens that some particles of that identical mud were imbedded in the carpet of Hilton Fenley's sitting-room. I'm sorry to have to say it, because the housemaid is a nice girl."