feet, and that the striking energy was 329—which gives a six-inch penetration in white pine at a distance of twenty-five yards.… An amazin’ creature, this Hagedorn. Imagine having one’s head full of such entrancing information! The old mysteries of why a man should take up the bass fiddle as a life work and where all the pins go are babes’ conundrums compared with the one of why a human being should devote his years to the idiosyncrasies of bullets.”
“The subject is not exactly an enthralling one,” said Markham wearily; “so, for the sake of argument, let us admit that you have now found the precise point of the gun’s explosion. Where do we go from there?”
“While I hold the string on a straight line,” directed Vance, “be good enough to measure the exact distance from the floor to the knot. Then my secret will be known.”
“This game doesn’t enthrall me, either,” Markham protested. “I’d much prefer ‘London Bridge’”
Nevertheless he made the measurement.
“Four feet, eight and a half inches,” he announced indifferently.
Vance laid a cigarette on the rug at a point directly beneath the knot.
“We now know the exact height at which the pistol was held when it was fired.… You grasp the process by which this conclusion was reached, I’m sure.”
“It seems rather obvious,” answered Markham.
Vance again went to the door and called Snitkin.
“The district attorney desires the loan of your gun for a moment,” he said. “He wishes to make a test.”
Snitkin stepped up to Markham and held out his pistol wonderingly.
“The safety’s on, sir. Shall I shift it?”
Markham was about to refuse the weapon when Vance interposed.
“That’s quite all right. Mr. Markham doesn’t intend to fire it—I hope.”
When the man had gone, Vance seated himself in the wicker chair and placed his head in juxaposition with the bullet hole.
“Now, Markham,” he requested, “will you please stand on the spot where the murderer stood, holding the gun directly above that cigarette on the floor, and aim delib’rately at my left temple.… Take care,” he cautioned, with an engaging smile, “not to pull the trigger, or you will never learn who killed Benson.”
Reluctantly Markham complied. As he stood taking aim Vance asked me to measure the height of the gun muzzle from the floor.
The distance was four feet and nine inches.
“Quite so,” he said, rising. “Y’ see, Markham, you are five feet, eleven inches tall; therefore the person who shot Benson was very nearly your own height—certainly not under five feet, ten.… That, too, is rather obvious, what?”
His demonstration had been simple and clear. Markham was frankly impressed; his manner had become serious. He regarded Vance for a moment with a meditative frown; then he said, “That’s all very well; but the person who fired the shot might have held the pistol relatively higher than I did.”
“Not tenable,” returned Vance. “I’ve done too much shooting myself not to know that when an expert takes delib’rate aim with a pistol at a small target, he does it with a stiff arm and with a slightly raised shoulder, so as to bring the sight on a straight line between his eye and the object at which he aims. The height at which one holds a revolver, under such conditions, pretty accurately determines his own height.”
“Your argument is based on the assumption that the person who killed Benson was an expert taking deliberate aim at a small target?”
“Not an assumption, but a fact,” declared Vance. “Consider: had the person not been an expert shot, he would not—at a distance of five or six feet—have selected the forehead but a larger target—namely, the breast. And having selected the forehead, he most certainly took delib’rate aim, what? Furthermore, had he not been an expert shot, and had he pointed the gun at the breast without taking delib’rate aim, he would, in all prob’bility, have fired more than one shot.”
Markham pondered. “I’ll grant that, on the face of it, your theory sounds plausible,” he conceded at length. “On the other hand, the guilty man could have been almost any height over five feet, ten; for certainly a man may crouch as much as he likes and still take deliberate aim.”
“True,” agreed Vance. “But don’t overlook the fact that the murderer’s position, in this instance, was a perfectly natural one. Otherwise, Benson’s attention would have been attracted, and he would not have been taken unawares. That he was shot unawares was indicated by his attitude. Of course, the assassin might have stooped a little without causing Benson to look up.… Let us say, therefore, that the guilty person’s height is somewhere between five feet, ten, and six feet, two. Does that appeal to you?”
Markham was silent.
“The delightful Miss St. Clair, y’ know,” remarked Vance, with a japish smile, “can’t possibly be over five feet, five or six.”
Markham grunted and continued to smoke abstractedly.
“This Captain Leacock, I take it,” said Vance, “is over six feet—eh, what?”
Markham’s eyes narrowed. “What makes you think so?”
“You just told me, don’t y’ know.”
“I told you!”
“Not in so many words,” Vance pointed out. “But after I had shown you the approximate height of the murderer, and it didn’t correspond at all to that of the young lady you suspected, I knew your active mind was busy looking around for another possibility. And, as the lady’s inamorato was the only other possibility on your horizon, I concluded that you were permitting your thoughts to play about the captain. Had he, therefore, been the stipulated height, you would have said nothing; but when you argued that the murderer might have stooped to fire the shot, I decided that the captain was inord’nately tall.… Thus, in the pregnant silence that emanated from you, old dear, your spirit held sweet communion with mine and told me that the gentleman was a six-footer no less.”
“I see that you include mind reading among your gifts,” said Markham. “I now await an exhibition of slate writing.”
His tone was irritable, but his irritation was that of a man reluctant to admit the alteration of his beliefs. He felt himself yielding to Vance’s guiding rein, but he still held stubbornly to the course of his own previous convictions.
“Surely you don’t question my demonstration of the guilty person’s height?” asked Vance mellifluously.
“Not altogether,” Markham replied. “It seems colorable enough.… But why, I wonder, didn’t Hagedorn work the thing out, if it was so simple?”
“Anaxagoras said that those who have occasion for a lamp supply it with oil. A profound remark, Markham—one of those seemingly simple quips that contain a great truth. A lamp without oil, y’ know, is useless. The police always have plenty of lamps—every variety, in fact—but no oil, as it were. That’s why they never find anyone unless it’s broad daylight.”
Markham’s mind was now busy in another direction, and he rose and began to pace the floor. “Until now I hadn’t thought of Captain Leacock as the actual agent of the crime.”
“Why hadn’t you thought of him? Was it because one of your sleuths told you he was at home like a good boy that night?”
“I suppose so.” Markham continued pacing thoughtfully. Then suddenly he swung about. “That wasn’t it, either. It was the amount of damning circumstantial evidence against the St. Clair woman.… And, Vance, despite your demonstration here today, you haven’t explained away any of the evidence against her. Where was she between twelve and one? Why did she go with Benson to dinner? How did her handbag