“No; just light cord. The archery buffs on the force tell me this stuff could never shoot an arrow; it would break at the first few pounds of pull.”
“Then your theory, I take it,” Middlebie said slowly, “is Cole, while Borden was in jail, plotted revenge, and learned, possibly, to shoot a bow with one hand. Then he went to Borden’s flat when the man was released, and familiarized himself with his habits, learning that Borden was apt to shave or wash between seven and eight. The cab driver was meant to be a witness of sorts — proof that Cole had no bow. The police-car merely added to his alibi — a sort of bonus.”
“That must be it,” Black said, rather glumly. “But with no bow, we don’t have a case. It’s barely possible he concealed a short one under his jacket, but if so, what happened to it?”
“You searched the roofs, of course.”
“Yes; they’re accessible only in a couple of places. In all the other ones, the buildings are four to six stories high; nobody could throw a stick up there. But we looked, anyhow. Nothing.”
“And a string on the arrow,” the professor murmured. “You realize that’s the key; it has to be. Anything that doesn’t fit is apt to be vital. Like the residue when nitrogen and oxygen were taken from a sample of air. The unexplained discrepancy led to the discovery of the inert gases — now no longer inert at all! Could he have wanted to pull the arrow back after it struck Borden? Why? And that has no connection with the missing bow, anyhow.” The gray eyes were turned inward. Then he looked at Sergeant Black again. “Do you have a copy of the medical report?”
“Right here, at your disposal.”
“Let me go over that, and do some thinking. I’m sure the data are available to us, and need only the prepared mind for resolution of the problem. Suppose you come back on Wednesday.”
“Good,” the sergeant said. He knew that once Middlebie put his great store of knowledge and insight to work, there was at least a chance to break this troublesome case. “I’ll be back then — unless,” he added hopefully, “I hear from you sooner. Tomorrow, say.”
“Not very likely,” was the dry comment. “Not even Faraday and Pasteur organized experimental data that fast, and I’m at best just playing the ape to their kind.” Black was about to deny this, but said nothing. The professor detested flattery, and often seemed suspicious of honest approval. It was not the worst trait a man could have, the sergeant thought; he knew some people couldn’t function without lavish and constant praise. They were the devil to deal with.
So he gave Middlebie a boyish grin, full of warmth more expressive than words, and said: “Good hunting, sir.” Then he left.
When Black had gone, the professor sat down at his huge, cluttered desk, and read the medical report. This done, he took pen and paper, and made some rather involved calculations, using a slide-rule from time to time. He studied his results, and his shaggy eyebrows rose. Interesting point, he thought. The arrow had been fired from an unusually weak bow — one of about fifteen pounds pull, his figures indicated — or else the archer had not drawn the string back more than a fraction of its normal range. It was a matter of basic physics. According to the medical report, the heavy, extremely sharp broadhead of steel had just severed the spinal cord. This relatively shallow penetration, when related to the known resistance of tissue, indicated the probable velocity of the arrow, from which the pull of the bow could easily be computed. Naturally it was not an exact determination, but the limits of error were known. Not more than fifteen pounds pulclass="underline" that was as certain as Newton’s Laws themselves.
He wondered then about the length of string: what was its breaking strength? Middlebie looked through some of the other papers in Black’s report. He felt a glow of pleasure at his one-time pupil’s competence. The boy had even checked the string. It broke at roughly three pounds of tension. It was obvious the stuff couldn’t have functioned as a bow-string.
The professor had a pretty good idea what he ought to do now. He began with the article on archery in the superb 11th Edition of the Encyclopedia, reading it through with great care. He learned much about an ancient and fascinating weapon, but nothing that helped Black’s case. Well, tomorrow he’d see what the university library had on archery, just in case. Meanwhile, there was another phase to work on.
He called the nearest sporting goods store, and had them send over a hunting arrow. When it arrived, he examined it closely, and then proceeded to experiment. Using a carefully calibrated spring device he improvised in his own well-stocked laboratory, he fired the arrow at a large block of wax which approximated human flesh in density. The experiment verified his calculations; the bow could not have had more than a fifteen pound pull.
The professor sat there, hefting the arrow in one hand. Suddenly his body tensed with excitement. He stood up, and gripping the center of the shaft, hurled the arrow with all his might at the wax target. It wobbled feebly through the air, struck the very edge of the wax block, then sagged to the floor. He tried several times from a distance of thirty feet, each shot being checked for penetration. He sighed, and put the arrow on the table. Another good idea gone to pot through experimentation. It obviously wasn’t possible to throw an arrow hard enough to kill a man at thirty feet. Aside from the problem of aiming it, which would seem to be bad enough, the flight path resembled that of a drunken owl in a high wind. Middlebie dropped the problem for that day. He had less faith than ever in tomorrow’s library work, but knew better than to skip it without a trial.
This attitude was fully justified by his session at the university. How odd that a book sixty years old should hold the secret to a recent murder. Yet there it was, in a fat tome called “The Crossbow”, just reprinted after more than half a century of neglect. The only trouble was, what should be done now? In theory, the puzzle was solved, but getting a conviction was not so simple. Besides, the professor, although perfectly law-abiding, wasn’t certain he wanted one.
In the circumstances, he decided to call on the suspect, who was still at home, under surveillance, but not arrest, the police being cautious about the lost bow.
He found Cole to be a thick-set, chunky man, whose face, once good-humored enough, the professor inferred from the wrinkle-lines of laughter at the corners of the eyes, was now a bitter mask. He walked stiffly, with great deliberation, and seemed charged with restlessness. His right arm, in the thin, short sleeve, was powerfully muscled, as if all the man’s strength was now concentrated there.
As Black had said, he was indeed laconic, so that Middlebie had to open the conversation, and carry most of it.
“So you see,” he told Cole gently, “the sergeant asked my help, your ingenuity having baffled him completely, as well it might.”
Cole said nothing, but his blue eyes, cold as polar ice, flickered briefly.
“Black thought there was a bow that disappeared, but we know better,” the professor added, his voice softer still.
“Do we?” Cole retorted, biting off his words almost like a snapping beast.
“I can understand your wanting to kill the man, but it’s possible the brakes did fail.”
“They didn’t. I was there. He never went for his brakes, but just tried to bull through. Too drunk and crazy to know it couldn’t be done.” Cole’s voice was full of fury.
“So you hated him, of course, and wanted revenge.”
“I didn’t say so.”
“You never say much. But you act. A vanishing breed, Black called you. Quite true. But you did kill — murder — him.”
“How? He was shot with an arrow, and there’s no bow connected with me. Therefore it must have been somebody else. Maybe his girl stabbed him with the arrow.” There was a feverish glint in the blue eyes now, as if Cole felt an urge to talk for once.