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- Guy Garrick - 40/43 -
"What are these?" I asked curiously, as he leaned back from his work, with a smile of quiet satisfaction.
"That is a collection of microphotographs which I have gathered," he answered, adding, "as well as some that I have just made. I hope to use them in a little stereopticon entertainment I am arranging to-night for those who have been interested in the case."
Garrick smiled. "Have you ever heard?" he asked, "that the rounded end of the firing pin of every rifle when it is examined under a microscope bears certain irregularities of marking different from those of every other firing pin and that the primer of every shell fired in a rifle is impressed with the particular markings of that firing pin?"
I had not, but Garrick went on, "I know that it is true. Such markings are distinctive for each rifle and can be made by no other. I have taken rifles bearing numbers preceding and following that of a particular one, as well as a large number of other firing pins. I have tried the rifles and the firing pins, one by one, and after I made microphotographs of the firing pins with special reference to the rounded ends and also photographs of the corresponding rounded depressions in the primers fired by them, it was forced upon me that cartridges fired by each individual firing pin could be positively identified."
I had been studying the photographs. It was a new idea, and it appealed to me strongly. "How about revolvers?" I asked quickly.
"Well, Dr. Balthazard, the French criminologist, has made experiments on the identification of revolver bullets and has a system that might be compared to that of Bertillon for identifying human beings. He has showed by greatly enlarged photographs that every gun barrel leaves marks on a bullet and that the marks are always the same for the same barrel but never identical for two different barrels. He has shown that the hammer of a revolver, say a centre fire, strikes the cartridge at a point which is never the exact centre of the cartridge, but is always the same for the same weapon. He has made negatives of bullets nearly a foot wide. Every detail appears very distinctly and it can be decided with absolute certainty whether a certain bullet or cartridge was fired by a certain revolver."
He had picked up one of the microphotographs and was looking at it attentively through a small glass.
"You will see," he explained, "on the edge of this photograph a rough sketch calling attention to a mark like an L which is the chief characteristic of this hammer, although there are other detailed markings which show well under the microscope but not in a photograph. You will note that the marks on a hammer are reversed on the primer in the same way that a metal type and the character printed by it are reversed as regards one another. Moreover, depressions on the end of a hammer become raised on the primer and raised markings on the hammer become depressions on the primer.
"Now, here is another. You can see that it is radically different from the first, which was from the cartridge used in killing poor Rena Taylor. This second one is from that gun which I found on the tenement roof this morning. It lacks the L mark as well as the concentric circles. Here is another. Its chief characteristics are a series of pits and elevations which, examined under the microscope and measured, will be found to afford a set of characters utterly different from those of any other hammer.
"In short," he concluded with an air of triumph, "the ends of firing pins are turned and finished in a lathe by the use of tools designed for that purpose. The metal tears and works unevenly so that microscopical examination shows many pits, lines, circles, and irregularities. The laws of chance are as much against two of these firing pins or hammers having the same appearance under the microscope as they are against the thumb prints of two human subjects being identical."
I picked up the curious little arrangement which we had found in the drawer in Forbes' room and examined it closely.
"I have been practicing with that pistol, if you may call it that," he remarked, "on cartridges of my own and examining the marks made by the peculiar hammer. I have studied marks of the gun which we found on the roof. I have compared them with the marks on cartridges which we have picked up at the finding of Rena Taylor's body, at the garage that night of the stupefying bullet, with bullets such as were aimed at Warrington, with others, both cartridges and bullets, at various times, and the conclusion is unescapable."
Who, I asked myself, was the scientific gunman? I knew it was useless to try to hurry Garrick. First, by a sort of intuition he had picked him out, then by the evidence of hammer and bullet he had made it practically certain. But I knew that to his scientific mind nothing but absolute certainty would suffice.
While I was waiting for him to proceed, he had already begun to work on some apparatus behind a screen at the end of his office. Close to the wall at the left was a stereopticon which, as nearly as I could make out, shot a beam of light through a tube to a galvanometer about three feet distant. In front of this beam whirled a five-spindled wheel governed by a chronometer which was so accurate, he said, that it erred only a second a day.
Between the poles of the galvanometer was stretched a slender thread of fused quartz plated with silver. It was the finest thread I could imagine, only a thousandth of a millimeter in diameter, far too tenuous to be seen. Three feet further away was a camera with a moving plate holder which carried a sensitized photographic plate. Its movement was regulated by a big fly-wheel at the extreme right.
"You see," remarked Garrick, now engrossed on the apparatus and forgetting the hammer evidence for the time, "the beam of light focussed on that fine thread in the galvanometer passes to this photographic plate. It is intercepted by the five spindles of the wheel, which turns once a second, thus marking the picture off in exact fifths of a second. The vibrations of the thread are enormously magnified on the plate by a lens and produce a series of wavy or zigzag lines. I have shielded the sensitized plate by a wooden hood which permits no light to strike it except the slender ray that is doing the work. The plate moves across the field slowly, its speed regulated by the fly-wheel. Don't you think it is neat and delicate? All these movements are produced by one of the finest little electric motors I ever saw."
I could not get the idea of the revolvers out of my head so quickly. I agreed with him, but all I could find to say was, "Do you think there was more than this one whom they call the Chief engaged in the shootings?"
"I can't say absolutely anything more than I have told you, yet," he answered in a tone that seemed to discourage further questioning along that line.
He continued to work on the delicate apparatus with its thread stretched between the stationary magnets of the galvanometer, a thread so delicate that it might have been spun by a microscopic spider, so light that no scales made by human hands could weigh it, so slender that the mind could hardly grasp it. It was about one-third the diameter of a red corpuscle of blood and its weight had been estimated as about .00685 milligrams, truly a fairy thread. It was finer than the most delicate cobweb and could be seen with the naked eye only when a strong light was thrown on it so as to catch the reflection.
"All I can say is," he admitted, "that the bullets which committed this horrible series of crimes have been proven all to be shot from the same gun, presumably, I think I shall show, by the same hand, and that hand is the same that wrote the blackmailing letter."
"Whose gun was it?" I asked. "Was there a way to connect it and the bullets and the cartridges with the owner--four things, all separated--and then that owner with the curious and tragic succession of events that had marked the case since the theft of Warrington's car?"
Garrick had apparently completed his present work of adjusting the delicate apparatus. He was now engaged on another piece which also had a powerful light in it and an attachment which bore a strong resemblance to a horn.
He paused a moment, regarding me quizzically. "I think you'll find it sufficiently novel to warrant your coming, Tom," he added. "I have already invited Dillon and his man, Herman, over the telephone just before you came in. McBirney will be there, and Forbes, of course. He'll have to come, if I want him. By the way, I wish you'd get in touch with Warrington and see how he is. If it is all right, tell him that I'd like to have him escort Miss Winslow and her aunt here, to-night. Meanwhile I shall find out how our friend the Boss is getting on. He ought to be here, at any cost, and I've put it off until to-night to make sure that he'll be in fit condition to come. To-night at nine--here in this office--remember," he concluded gayly. "In the meantime, not a word to anybody about what you have seen here this afternoon."
THE SCIENTIFIC GUNMAN
Our little audience arrived one by one, and, as master of ceremonies, it fell to me to greet them and place them as much at ease as the natural tension of the occasion would permit. Garrick spoke a word or two to each, but was still busy putting the finishing touches on the preparations for the "entertainment," as he called it facetiously, which he had arranged.
"Before I put to the test a rather novel combination which I have arranged," began Garrick, when they had all been seated, "I want to say a few words about some of the discoveries I have already made in this remarkable case."
He paused a moment to make sure that he had our attention, but it was unnecessary. We were all hanging eagerly on his words.
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