The Case of the Scientific Murderer

Certainly no problem that ever came to the attention of The Thinking Machine required in a greater degree subtlety of mind, exquisite analytical sense, and precise knowledge of the marvels of science than did that singular series of events which began with the death of the Honorable Violet Danbury, only daughter and sole heir of the late Sir Duval Danbury, of Leamington, England. In this case The Thinking Machine—more properly, Professor Augustus S. F. X. Van Dusen, Ph. D., M. D., F. R. S., et cetera, et cetera—brought to bear upon an extraordinary mystery of crime that intangible genius of logic which had made him the court of last appeal in his profession. “Logic is inexorable,” he has said; and no greater proof of his assertion was possible than in this instance where literally he seemed to pluck a solution of the riddle from the void.

Shortly after eleven o’clock on the morning of Thursday, May 4, Miss Danbury was found dead, sitting in the drawing-room of apartments she was temporarily occupying in a big family hotel on Beacon Street. She was richly gowned, just as she had come from the opera the night before; her marble-white bosom and arms aglitter with jewels. On her face, dark in death as are the faces of those who die of strangulation, was an expression of unspeakable terror. Her parted lips were slightly bruised, as if from a light blow; in her left cheek was an insignificant, bloodless wound. On the floor at her feet was a shattered goblet. There was nothing else unusual, no disorder, no sign of a struggle. Obviously she had been dead for several hours.

All these things considered, the snap judgement of the police—specifically, the snap judgement of Detective Mallory, of the bureau of criminal investigation—was suicide by poison. Miss Danbury had poured some deadly drug into a goblet, sat down, drained it off, and died. Simple and obvious enough. But the darkness in her face? Oh, that! Probably some effect of a poison he didn’t happen to be acquainted with. But it looked as if she might have been strangled! Pooh! Pooh! There were no marks on her neck, of fingers or anything else. Suicide, that’s what it was—the autopsy would disclose the nature of the poison.

Cursory questions of the usual nature were asked and answered. Had Miss Danbury lived alone? No; she had a companion upon whom, too, devolved the duties of chaperon—a Mrs. Cecelia Montgomery. Where was she? She’d left the city the day before to visit friends in Concord; the manager of the hotel had telegraphed the facts to her. No servants? No. She had availed herself of the service in the hotel. Who had last seem Miss Danbury alive? The elevator attendant the night before, when she had returned form the opera, about half past eleven o’clock. Had she gone alone? No. She had been accompanied by Professor Charles Meredith, of the university. He had returned with her, and left her at the elevator.

“How did she come to know Professor Meredith?” Mallory inquired. “Friend, relative——”

“I don’t know,” said the hotel manager. “She knew a great many people here. She’d only been in the city two months this time, but once, three years ago, she spent six months here.”

“Any particular reason for her coming over? Business, for instance, or merely a visit?”

“Merely a visit, I imagine.”

The front door swung open, and there entered at the moment a middle-aged man, sharp-featured, rather spare, brisk in his movements, and distinctly well groomed. He went straight to the inquiry desk.

“Will you please phone to Miss Danbury, and ask her if she will join Mr. Herbert Willing for luncheon at the country club?” he requested. “Tell her I am below with my motor.”

At mention of Miss Danbury’s name both Mallory and the house manager turned. The boy behind the inquiry desk glanced at the detective blankly. Mr. Willing rapped upon the desk sharply.

“Well, well?” he demanded impatiently. “Are you asleep?”

“Good morning, Mr. Willing,” Mallory greeted him.

“Hello, Mallory,” and Mr. Willing turned to face him. “What are you doing here?”

“You don’t know that Miss Danbury is”—the detective paused a little—“is dead?”

“Dead!” Mr. Willing gasped. “Dead!” he repeated incredulously. “What are you talking about?” He seized Mallory by the arm, and shook him. “Miss Danbury is——”

“Dead,” the detective assured him again. “She probably committed suicide. She was found in her apartments two hours ago.”

For half a minute Mr. Willing continued to stare at him as if without comprehension, then he dropped weakly into a chair, with his head in his hands. When he glanced up again there was deep grief in his keen face.

“It’s my fault,” he said simply. “I feel like a murderer. I gave her some bad news yesterday, but I didn’t dream she would——” He stopped.

“Bad news?” Mallory urged.

“I’ve been doing some legal work for her,” Mr. Willing explained. “She’s been trying to sell a huge estate in England, and just at the moment the deal seemed assured it fell through. I—I suppose it was a mistake to tell her. This morning I received another offer from an unexpected quarter, and I came by to inform her of it.” He stared tensely into Mallory’s face for a moment without speaking. “I feel like her murderer!” he said again.

“But I don’t understand why the failure of the deal——” the detective began; then: “She was rich, wasn’t she? What did it matter particularly if the deal did fail?”

“Rich, yes; but land poor,” the lawyer elucidated. “The estates to which she held title were frightfully involved. She had jewels and all those things, but see how simply she lived. She was actually in need of money. It would take me an hour to make you understand. How did she die? When? What was the manner of her death?”

Detective Mallory placed before him those facts he had, and finally went away with him in his motor car to see Professor Meredith at the university. Nothing bearing on the case developed as the result of that interview. Mr. Meredith seemed greatly shocked, and explained that his acquaintance with Miss Danbury dated some weeks back, and friendship had grown out of it through a mutual love of music. He had accompanied her to the opera half a dozen times.

“Suicide!” the detective declared, as he came away. “Obviously suicide by poison.”

On the following day he discovered for the first time that the obvious is not necessarily true. The autopsy revealed absolutely no trace of poison, either in the body or clinging to the shattered goblet, carefully gathered up and examined. The heart was normal, showing neither constriction nor dilation, as would have been the case had poison been swallowed, or even inhaled.

“It’s the small wound in her cheek, then,” Mallory asserted. “Maybe she didn’t swallow or inhale poison—she injected it directly into her blood through that wound.”

“No,” one of the examining physicians pointed out. “Even that way the heart would have shown constriction or dilation.”

“Oh, maybe not,” Mallory argued hopefully.

“Besides,” the physician went on, “that wound was made after death. That is proven by the fact that it did not bleed.” His brow clouded in perplexity. “There doesn’t seem to be the slightest reason for that wound, anyway. It’s really a hole, you know. It goes straight through her cheek. It looks as if it might have been made with a large hatpin.”

The detective was staring at him. If that wound had been made after death, certainly Miss Danbury didn’t make it—she had been murdered! And not murdered for robbery, since her jewels had been undisturbed.

“Straight through her cheek!” he repeated blankly. “By George! Say, if it wasn’t poison, what killed her?”

The three examining physicians exchanged glances.

“I don’t know that I can make you understand,” said one. “She died of absence of air in her lungs, if you follow me.”

“Absence of air—well, that’s illuminating!” the detective sneered heavily. “You mean she was strangled, or choked to death?”

“I mean precisely what I say,” was the reply. “She was not strangled—there is no mark on her throat; or choked—there is no obstruction in her throat. Literally she died of absence of air in her lungs.”

Mallory stood silently glowering at them. A fine lot of physicians, these!

“Let’s understand one another,” he said at last. “Miss Danbury did not die a natural death?”

“No!” emphatically.

“She wasn’t poisoned? Or strangled? Or shot? Or stabbed? Or run over by a truck? Or blown up by dynamite? Or kicked by a mule? Nor,” he concluded, “did she fall from an aëroplane?”

“No.”

“In other words, she just quit living?”

“Something like that,” the physician admitted. He seemed to be seeking a means of making himself more explicit. “You know the old nursery theory that a cat will suck a sleeping baby’s breath?” he asked. “Well, the death of Miss Danbury was like that, if you understand. It is as if some great animal or—or thing had——” He stopped.

Detective Mallory was an able man, the ablest, perhaps, in the bureau of criminal investigation, but a yellow primrose by the river’s brim was to him a yellow primrose, nothing more. He lacked imagination, a common fault of that type of sleuth who combines, more or less happily, a number eleven shoe and a number six hat. The only vital thing he had to go on was the fact that Miss Danbury was dead—murdered, in some mysterious, uncanny way. Vampires were something like that, weren’t they? He shuddered a little.

“Regular vampire sort of thing,” the youngest of the three physicians remarked, echoing the thought in the detective’s mind. “They’re supposed to make a slight wound, and——”

Detective Mallory didn’t hear the remainder of it. He turned abruptly, and left the room.

On the following Monday morning, one Henry Sumner, a longshoreman in Atlantic Avenue, was found dead sitting in his squalid room. On his face, dark in death, as are the faces of those who die of strangulation, was an expression of unspeakable terror. His parted lips were slightly bruised, as if from a light blow; in his left cheek was an insignificant, bloodless wound. On the floor at his feet was a shattered drinking glass!

’Twas Hutchinson Hatch, newspaper reporter, long, lean, and rather prepossessing in appearance, who brought this double mystery to the attention of The Thinking Machine. Martha, the eminent scientist’s one servant, admitted the newspaper man, and he went straight to the laboratory. As he opened the door The Thinking Machine turned testily from his worktable.

“Oh, it’s you, Mr. Hatch. Glad to see you. Sit down. What is it?” That was his idea of extreme cordiality.

“If you can spare me five minutes?” the reporter began apologetically.

“What is it?” repeated The Thinking Machine, without raising his eyes.

“I wish I knew,” the reporter said ruefully. “Two persons are dead—two persons as widely apart as the poles, at least in social position, have been murdered in precisely the same manner, and it seems impossible that——”

“Nothing is impossible,” The Thinking Machine interrupted, in the tone of perpetual irritation which seemed to be a part of him. “You annoy me when you say it.”

“It seems highly improbable,” Hatch corrected himself, “that there can be the remotest connection between the crimes, yet——”

“You’re wasting words,” the crabbed little scientist declared impatiently. “Begin at the beginning. Who was murdered? When? How? Why? What was the manner of death?”

“Taking the last question first,” the reporter explained, “we have the most singular part of the problem. No one can say the manner of death, not even the physicians.”

“Oh!” For the first time The Thinking Machine lifted his petulant, squinting, narrowed eyes, and stared into the face of the newspaper man. “Oh!” he said again. “Go on.”

As Hatch talked, the lure of a material problem laid hold of the master mind, and after a little The Thinking Machine dropped into a chair. With his great, grotesque head tilted back, his eyes turned steadily upward, and slender fingers placed precisely tip to tip, he listened in silence to the end.

“We come now,” said the newspaper man, “to the inexplicable after developments. We have proven that Mrs. Cecelia Montgomery, Miss Danbury’s companion, did not go to Concord to visit friends; as a matter of fact, she is missing. The police have been able to find no trace of her, and to-day are sending out a general alarm. Naturally, her absence at this particular moment is suspicious. It is possible to conjecture her connection with the death of Miss Danbury, but what about——”

“Never mind conjecture,” the scientist broke in curtly. “Facts, facts!”

“Further,” and Hatch’s bewilderment was evident on his face, “mysterious things have been happening in the rooms where Miss Danbury and this man Henry Sumner were found dead. Miss Danbury was found dead last Thursday. Immediately after the body was removed, Detective Mallory ordered her room locked, his idea being that nothing should be disturbed at least for the present, because of the strange circumstances surrounding her death. When the nature of the Henry Sumner affair became known, and the similarity of the cases recognized, he gave the same order regarding Sumner’s room.”

Hatch stopped, and stared vainly into the pallid, wizened face of the scientist. A curious little chill ran down his spinal column.

“Some time Tuesday night,” he continued, after a moment, “Miss Danbury’s room was entered and ransacked; and some time that same night Henry Sumner’s room was entered and ransacked. This morning, Wednesday, a clearly defined hand print in blood was found in Miss Danbury’s room. It was on the wooden top of a dressing table. It seemed to be a woman’s hand. Also, an indistinguishable smudge of blood, which may have been a hand print, was found in Sumner’s room!” He paused; The Thinking Machine’s countenance was inscrutable. “What possible connection can there be between this young woman of the aristocracy, and this—this longshoreman? Why should——”

“What chair,” questioned The Thinking Machine, “does Professor Meredith hold in the university?”

“Greek,” was the reply.

“Who is Mr. Willing?”

“One of the leading lawyers of the city.”

“Did you see Miss Danbury’s body?”

“Yes.”

“Did she have a large mouth, or a small mouth?”

The irrelevancy of the questions, to say nothing of their disjointedness, brought a look of astonishment to Hatch’s face; and he was a young man who was rarely astonished by the curious methods of The Thinking Machine. Always he had found that the scientist approached a problem from a new angle.

“I should say a small mouth,” he ventured. “Her lips were bruised as if—as if something round, say the size of a twenty-five-cent piece, had been crushed against them. There was a queer, drawn, caved-in look to her mouth and cheeks.”

“Naturally,” commented The Thinking Machine enigmatically. “And Sumner’s was the same?”

“Precisely. You say ‘naturally.’ Do you mean——” There was eagerness in the reporter’s question.

It passed unanswered. For half a minute The Thinking Machine continued to stare into nothingness. Finally:

“I dare say Sumner was of the English type? His name is English?”

“Yes; a splendid physical man, a hard drinker, I hear, as well as a hard worker.”

Again a pause.

“You don’t happen to know if Professor Meredith is now or ever has been particularly interested in physics—that is, in natural philosophy?”

“I do not.”

“Please find out immediately,” the scientist directed tersely. “Willing has handled some legal business for Miss Danbury. Learn what you can from him to the general end of establishing some connection, a relationship possibly, between Henry Sumner and the Honorable Violet Danbury. That, at the moment, is the most important thing to do. Neither of them may have been aware of the relationship, if relationship it was, yet it may have existed. If it doesn’t exist, there’s only one answer to the problem.”

“And that is?” Hatch asked.

“The murders are the work of a madman,” was the tart rejoinder. “There’s no mystery, of course, in the manner of the deaths of these two.”

“No mystery?” the reporter echoed blankly. “Do you mean you know how they——”

“Certainly I know, and you know. The examining physicians know, only they don’t know that they know.” Suddenly his tone became didactic. “Knowledge that can’t be applied is utterly useless,” he said. “The real difference between a great mind and a mediocre mind is only that the great mind applies its knowledge.” He was silent a moment. “The only problem remaining here is to find the person who was aware of the many advantages of this method of murder.”

“Advantages?” Hatch was puzzled.

“From the viewpoint of the murderer there is always a good way and a bad way to kill a person,” the scientist told him. “This particular murderer chose a way that was swift, silent, simple, and sure as the march of time. There was no scream, no struggle, no pistol shot, no poison to be traced, nothing to be seen except——”

“The hole in the left cheek, perhaps?”

“Quite right, and that leaves no clew. As a matter of fact, the only clew we have at all is the certainty that the murderer, man or woman, is well acquainted with physics, or natural philosophy.”

“Then you think,” the newspaper man’s eyes were about to start from his head, “that Professor Meredith——”

“I think nothing,” The Thinking Machine declared briefly. “I want to know what he knows of physics, as I said; also I want to know if there is any connection between Miss Danbury and the longshoreman. If you’ll attend to——”

Abruptly the laboratory door opened and Martha entered, pallid, frightened, her hands shaking.

“Something most peculiar, sir,” she stammered in her excitement.

“Well?” the little scientist questioned.

“I do believe,” said Martha, “that I’m a-going to faint!”

And as an evidence of good faith she did, crumpling up in a little heap before their astonished eyes.

“Dear me! Dear me!” exclaimed The Thinking Machine petulantly. “Of all the inconsiderate things! Why couldn’t she have told us before she did that?”

It was a labor of fifteen minutes to bring Martha around, and then weakly she explained what had happened. She had answered a ring of the telephone, and some one had asked for Professor Van Dusen. She inquired the name of the person talking.

“Never mind that,” came the reply. “Is he there? Can I see him?”

“You’ll have to explain what you want, sir,” Martha had told him. “He always has to know.”

“Tell him I know who murdered Miss Danbury and Henry Sumner,” came over the wire. “If he’ll receive me I’ll be right up.”

“And then, sir,” Martha explained to The Thinking Machine, “something must have happened at the other end, sir. I heard another man’s voice, then a sort of a choking sound, sir, and then they cursed me, sir. I didn’t hear any more. They hung up the receiver or something, sir.” She paused indignantly. “Think of him, sir, a-swearing at me!”

For a moment the eyes of the two men met; the same thought had come to them both. The Thinking Machine voiced it.

“Another one!” he said. “The third!”

With no other word he turned and went out; Martha followed him grumblingly. Hatch shuddered a little. The hand of the clock went on to half past seven, to eight. At twenty minutes past eight the scientist reëntered the laboratory.

“That fifteen minutes Martha was unconscious probably cost a man’s life, and certainly lost to us an immediate solution of the riddle,” he declared peevishly. “If she had told us before she fainted there is a chance that the operator would have remembered the number. As it is, there have been fifty calls since, and there’s no record.” He spread his slender hands helplessly. “The manager is trying to find the calling number. Anyway, we’ll know to-morrow. Meanwhile, try to see Mr. Willing to-night, and find out about what relationship, if any, exists between Miss Danbury and Sumner; also, see Professor Meredith.”

The newspaper man telephoned to Mr. Willing’s home in Melrose to see if he was in; he was not. On a chance he telephoned to his office. He hardly expected an answer, and he got none. So it was not until four o’clock in the morning that the third tragedy in the series came to light.

The scrubwomen employed in the great building where Mr. Willing had his law offices entered the suite to clean up. They found Mr. Willing there, gagged, bound hand and foot, and securely lashed to a chair. He was alive, but apparently unconscious from exhaustion. Directly facing him his secretary, Maxwell Pittman, sat dead in his chair. On his face, dark in death, as are the faces of those who die of strangulation, was an expression of unspeakable terror. His parted lips were slightly bruised, as if from a light blow; in his left cheek was an insignificant, bloodless wound!

Within an hour Detective Mallory was on the scene. By that time Mr. Willing, under the influence of stimulants, was able to talk.

“I have no idea what happened,” he explained. “It was after six o’clock, and my secretary and I were alone in the offices, finishing up some work. He had stepped into another room for a moment, and I was at my desk. Some one crept up behind me, and held a drugged cloth to my nostrils. I tried to shout, and struggled, but everything grew black, and that’s all I know. When I came to myself poor Pittman was there, just as you see him.”

Snooping about the offices, Mallory came upon a small lace handkerchief. He seized upon it tensely, and as he raised it to examine it he became conscious of a strong odor of drugs. In one corner of the handkerchief there was a monogram.

“ ‘C. M.,’ ” he read; his eyes blazed. “Cecelia Montgomery!”

In the grip of an uncontrollable excitement Hutchinson Hatch bulged in upon The Thinking Machine in his laboratory.

“There was another,” he announced.

“I know it,” said The Thinking Machine, still bent over his worktable. “Who was it?”

“Maxwell Pittman,” and Hatch related the story.

“There may be two more,” the scientist remarked. “Be good enough to call a cab.”

“Two more?” Hatch gasped in horror. “Already dead?”

“There may be, I said. One, Cecelia Montgomery, the other the unknown who called on the telephone last night.” He started away, then returned to his worktable. “Here’s rather an interesting experiment,” he said. “See this tube,” and he held aloft a heavy glass vessel, closed at one end, and with a stopcock at the other. “Observe. I’ll place this heavy piece of rubber over the mouth of the tube, and then turn the stopcock.” He suited the action to the word. “Now take it off.”

The reporter tugged at it until the blood rushed to his face, but was unable to move it. He glanced up at the scientist in perplexity.

“What hold it there?”

“Vacuum,” was the reply. “You may tear it to pieces, but no human power can pull it away whole.” He picked up a steel bodkin, and thrust it through the rubber into the mouth of the tube. As he withdrew it, came a sharp, prolonged, hissing sound. Half a minute later the rubber fell off. “The vacuum is practically perfect—something like one-millionth of an atmosphere. The pin hole permits the air to fill the tube, the tremendous pressure against the rubber is removed, and——” He waved his slender hands.

In that instant a germ of comprehension was born in Hatch’s brain; he was remembering some college experiments.

“If I should place that tube to your lips,” The Thinking Machine resumed, “and turn the stopcock, you would never speak again, never scream, never struggle. It would jerk every particle of air out of your body, paralyze you; within two minutes you would be dead. To remove the tube I should thrust the bodkin through your cheek, say your left, and withdraw it——”

Hatch gasped as the full horror of the thing burst upon him. “Absence of air in the lungs,” the examining physicians had said.

“You see, there was no mystery in the manner of the deaths of these three,” The Thinking Machine pointed out. “You knew what I have shown you, the physicians knew it, but neither of you knew you knew it. Genius is the ability to apply the knowledge you may have, not the ability to acquire it.” His manner changed abruptly. “Please call a cab,” he said again.

Together they were driven straight to the university, and shown into Professor Meredith’s study. Professor Meredith showed his astonishment plainly at the visit, and astonishment became indignant amazement at the first question.

“Mr. Meredith, can you account for every moment of your time from mid-afternoon yesterday until four o’clock this morning?” The Thinking Machine queried flatly. “Don’t misunderstand me—I mean every moment covering the time in which it is possible that Maxwell Pittman was murdered?”

“Why, it’s a most outrageous——” Professor Meredith exploded.

“I’m trying to save you from arrest,” the scientist explained curtly. “If you can account for all that time, and prove your statement, believe me, you had better prepare to do so. Now, if you could give me any information as to——”

“Who the devil are you?” demanded Professor Meredith belligerently. “What do you mean by daring to suggest——”

“My name is Van Dusen,” said The Thinking Machine, “Augustus S. F. X. Van Dusen. Long before your time I held the chair of philosophy in this university. I vacated it by request. Later the university honored me with a degree of LL. D.”

The result of the self-introduction was astonishing. Professor Meredith, in the presence of the master mind in the sciences, was a different man.

“I beg you pardon,” he began.

“I’m curious to know if you are at all acquainted with Miss Danbury’s family history,” the scientist went on. “Meanwhile, Mr. Hatch, take the cab, and go straight and measure the precise width of the bruise on Pittman’s lips; also, see Mr. Willing, if he is able to receive you, and ask him what he can give you as to Miss Danbury’s history—I mean her family, her property, her connections, all about everything. Meet me at my house in a couple of hours.”

Hatch went out, leaving them together. When he reached the scientist’s home The Thinking Machine was just coming out.

“I’m on my way to see Mr. George Parsons, the so-called copper king,” he volunteered. “Come along.”

From that moment came several developments so curious, and bizarre, and so widely disassociated that Hatch could make nothing of them at all. Nothing seemed to fit into anything else. For instance, The Thinking Machine’s visit to Mr. Parsons’ office.

“Please ask Mr. Parsons if he will see Mr. Van Dusen?” he requested of an attendant.

“What about?” the query came from Mr. Parsons.

“It is a matter of life and death,” the answer went back.

“Whose?” Mr. Parsons wanted to know.

“His!” The scientist’s answer was equally short.

Immediately afterward The Thinking Machine disappeared inside. Ten minutes later he came out, and he and Hatch went off together, stopping at a toy shop to buy a small, high-grade, hard-rubber ball; and later at a department store to purchase a vicious-looking hatpin.

“You failed to inform me, Mr. Hatch, of the measurement of the bruise?”

“Precisely one and a quarter inches.”

“Thanks! And what did Mr. Willing say?”

“I didn’t see him as yet. I have an appointment to see him in an hour from now.”

“Very well,” and The Thinking Machine nodded his satisfaction. “When you see him, will you be good enough to tell him, please, that I know—I know, do you understand?—who killed Miss Danbury, and Sumner, and Pittman. You can’t make it too strong. I know—do you understand?”

“Do you know?” Hatch demanded quickly.

“No,” frankly. “But convince him that I do, and add that to-morrow at noon I shall place the extraordinary facts I have gathered in possession of the police. At noon, understand; and I know!” He was thoughtful a moment. “You might add that I have informed you that the guilty person is a person of high position, whose name has been in no way connected with the crimes—that is, unpleasantly. You don’t know that name; no one knows it except myself. I shall give it to the police at noon to-morrow.”

“Anything else?”

“Drop in on me early to-morrow morning, and bring Mr. Mallory.”

Events were cyclonic on that last morning. Mallory and Hatch had hardly arrived when there came a telephone message for the detective from police headquarters. Mrs. Cecelia Montgomery was there. She had come in voluntarily, and asked for Mr. Mallory.

“Don’t rush off now,” requested The Thinking Machine, who was pottering around among the retorts, and microscopes and what not on his worktable. “Ask them to detain her until you get there. Also, ask her just what relationship existed between Miss Danbury and Henry Sumner.” The detective went out; the scientist turned to Hatch. “Here is a hatpin,” he said. “Some time this morning we shall have another caller. If, during the presence of that person in this room, I voluntarily put anything to my lips, a bottle, say, or anything is forced upon me, and I do not remove it in just thirty seconds, you will thrust this hatpin through my cheek. Don’t hesitate.”

“Thrust it through?” the reporter repeated. An uncanny chill ran over him as he realized the scientist’s meaning. “Is it absolutely necessary to take such a chance to——”

“I say if I don’t remove it!” The Thinking Machine interrupted shortly. “You and Mallory will be watching from another room; I shall demonstrate the exact manner of the murders.” There was a troubled look in the reporter’s face. “I shall be in no danger,” the scientist said simply. “The hatpin is merely a precaution if anything should go wrong.”

After a little Mallory entered, with clouded countenance.

“She denies the murders,” he announced, “but admits that the hand prints in blood are hers. According to her yarn, she searched Miss Danbury’s room and Sumner’s room after the murders to find some family papers which were necessary to establish claims to some estate—I don’t quite understand. She hurt her hand in Miss Danbury’s room, and it bled a lot, hence the hand print. From there she went straight to Sumner’s room, and presumably left the smudge there. It seems that Sumner was a distant cousin of Miss Danbury’s—the only son of a younger brother who ran away years ago after some wild escapade, and came to this country. George Parsons, the copper king, is the only other relative in this country. She advises us to warn him to be on his guard—seems to think he will be the next victim.”

“He’s already warned,” said The Thinking Machine, “and he has gone West on important business.”

Mallory stared.

“You seem to know more about this case than I do,” he sneered.

“I do,” asserted the scientist, “quite a lot more.”

“I think the third degree will change Mrs. Montgomery’s story some,” the detective declared. “Perhaps she will remember better——”

“She is telling the truth.”

“Then why did she run away? How was it we found her handkerchief in Mr. Willing’s office after the Pittman affair? How was it——”

The Thinking Machine shrugged his shoulders, and was silent. A moment later the door opened, and Martha appeared, her eyes blazing with indignation.

“That man who swore at me over the telephone,” she announced distinctly, “wants to see you, sir.”

Mallory’s keen eyes swept the faces of the scientist and the reporter, trying to fathom the strange change that came over them.

“You are sure, Martha?” asked The Thinking Machine.

“Indeed I am, sir.” She was positive about it. “I’d never forget his voice, sir.”

For an instant her master merely stared at her, then dismissed her with a curt, “Show him in,” after which he turned to the detective and Hatch.

“You will wait in the next room,” he said tersely. “If anything happens, Mr. Hatch, remember.”

The Thinking Machine was sitting when the visitor entered—a middle-aged man, sharp-featured, rather spare, brisk in his movements, and distinctly well groomed. It was Herbert Willing, attorney. In one hand he carried a small bag. He paused an instant, and gazed at the diminutive scientist curiously.

“Come in, Mr. Willing,” The Thinking Machine greeted. “You want to see me about——” He paused questioningly.

“I understand,” said the lawyer suavely, “that you have interested yourself in these recent—er—remarkable murders, and there are some points I should like to discuss with you. I have some papers in my bag here, which”—he opened it—“may be of interest. Some er—newspaper man informed me that you have certain information indicating the person——”

“I know the name of the murderer,” said The Thinking Machine.

“Indeed! May I ask who it is?”

“You may. His name is Herbert Willing.”

Watching tensely Hatch saw The Thinking Machine pass his hand slowly across his mouth as if to stifle a yawn; saw Willing leap forward suddenly with what seemed to be a bottle in his hand; saw him force the scientist back into his chair, and thrust the bottle against his lips. Instantly came a sharp click, and some hideous change came over the scientist’s wizened face. His eyes opened wide in terror, his cheeks seemed to collapse. Instinctively he grasped the bottle with both hands.

For a scant second Willing stared at him, his countenance grown demoniacal; then he swiftly took something else from the small bag, and smashed it on the floor. It was a drinking glass!

After which the scientist calmly removed the bottle from his lips.

“The broken drinking glass,” he said quietly, “completes the evidence.”

Hutchinson Hatch was lean and wiry, and hard as nails; Detective Mallory’s bulk concealed muscles of steel, but it took both of them to overpower the attorney. Heedless of the struggling trio The Thinking Machine was curiously scrutinizing the black bottle. The mouth was blocked by a small rubber ball, which he had thrust against it with his tongue a fraction of an instant before the dreaded power the bottle held had been released by pressure upon a cunningly concealed spring. When he raised his squinting eyes at last, Willing, manacled, was glaring at him in impotent rage. Fifteen minute later the four were at police headquarters; Mrs. Montgomery was awaiting them.

“Mrs. Montgomery, why,”—and the petulant pale-blue eyes of The Thinking Machine were fixed upon her face—“why didn’t you go to Concord, as you had said?”

“I did go there,” she replied. “It was simply that when news came of Miss Danbury’s terrible death I was frightened, I lost my head; I pleaded with my friends not to let it be known that I was there, and they agreed. If any one had searched their house I would have been found; no one did. At last I could stand it no longer. I came to the city, and straight here to explain everything I knew in connection with the affair.”

“And the search you made of Miss Danbury’s room? And of Sumner’s room?”

“I’ve explained that,” she said. “I knew of the relationship between poor Harry Sumner and Violet Danbury, and I knew each of them had certain papers which were of value as establishing their claims to a great estate in England now in litigation. I was sure those papers would be valuable to the only other claimant, who was——”

“Mr. George Parsons, the copper king,” interposed the scientist. “You didn’t find the papers you sought because Willing had taken them. That estate was the thing he wanted, and I dare say by some legal jugglery he would have gotten it.” Again he turned to face Mrs. Montgomery. “Living with Miss Danbury, as you did, you probably held a key to her apartment? Yes. You had only the difficulty then, of entering the hotel late at night, unseen, and that seemed to be simple. Willing did it the night he killed Miss Danbury, and left it unseen, as you did. Now, how did you enter Sumner’s room?”

“It was a terrible place,” and she shuddered slightly. “I went in alone, and entered his room through a window from a fire escape. The newspapers, you will remember, described its location precisely, and——”

“I see,” The Thinking Machine interrupted. He was silent a moment. “You’re a shrewd man, Willing, and your knowledge of natural philosophy is exact if not extensive. Of course, I knew if you thought I knew too much about the murders you would come to me. You did. It was a trap, if that’s any consolation to you. You fell into it. And, curiously enough, I wasn’t afraid of a knife or a shot; I knew the instrument of death you had been using was too satisfactory and silent for you to change. However, I was prepared for it, and—I think that’s all.” He arose.

“All?” Hatch and Mallory echoed the word. “We don’t understand——”

“Oh!” and The Thinking Machine sat down again. “It’s logic. Miss Danbury was dead—neither shot, stabbed, poisoned, nor choked; ‘absence of air in her lungs,’ the physicians said. Instantly the vacuum bottle suggested itself. That murder, as was the murder of Sumner, was planned to counterfeit suicide, hence the broken goblet on the floor. Incidentally the murder of Sumner informed me that the crimes were the work of a madman, else there was an underlying purpose which might have arisen through a relationship. Ultimately I established that relationship through Professor Meredith, in whom Miss Danbury had confided to a certain extent; at the same time he convinced me of his innocence in the affair.

“Now,” he continued, after a moment, “we come to the murder of Pittman. Pittman learned, and tried to phone me, who the murderer was. Willing heard that message. He killed Pittman, then bound and gagged himself, and waited. It was a clever ruse. His story of being overpowered and drugged is absurd on the face of it, yet he asked us to believe that by leaving a handkerchief of Mrs. Montgomery’s on the floor. That was reeking with drugs. Mr. Hatch can give you more of these details.” He glanced at his watch. “I’m due at a luncheon, where I am to make an address to the Society of Psychical Research. If you’ll excuse me——”

He went out; the others sat staring after him.