Captain Hank Barber, master mariner, gripped the bow-rail of the Liddy Ann and peered off through the semi-fog of the early morning at a dark streak slashing along through the gray-green waters. It was a motor boat of long, graceful lines; and a single figure, that of a man, sat upright at her helm staring uncompromisingly ahead. She nosed through a roller, staggered a little, righted herself and sped on as a sheet of spray swept over her. The helmsman sat motionless, heedless of the stinging splash of wind driven water in his face.

“She sure is a-goin’ some,” remarked Captain Hank, reflectively. “By Ginger! If she keeps it up into Boston Harbour she won’t stop this side o’ the Public Gardens.”

Captain Hank watched the boat curiously until she was swallowed up, lost in the mist, then turned to his own affairs. He was a couple of miles out of Boston Harbour, going in; it was six o’clock of a gray morning. A few minutes after the disappearance of the motor boat Captain Hank’s attention was attracted by the hoarse shriek of a whistle two hundred yards away. He dimly traced through the mist the gigantic lines of a great vessel — it seemed to be a ship of war.

It was only a few minutes after Captain Hank lost sight of the motor boat that she was again sighted, this time as she flashed into Boston Harbour at full speed. She fled past, almost under the prow of a pilot boat, going out, and was hailed. At the mess table later the pilot’s man on watch made a remark about her.

“Goin’! Well, wasn’t she though! Never saw one thing pass so close to another in my life without scrubbin’ the paint offen it. She was so close up I could spit in her, and when I spoke the feller didn’t even look up — just kept a-goin’. I told him a few things that was good for his soul.”

Inside Boston Harbour the motor boat performed a miracle. Pursuing a course which was singularly erratic and at a speed more than dangerous she reeled on through the surge of the sea regardless alike of fog, the proximity of other vessels and the heavy wash from larger craft. Here she narrowly missed a tug; there she skimmed by a slow moving tramp and a warning shout was raised; a fisherman swore at her as only a fisherman can. And finally when she passed into a clear space, seemingly headed for a dock at top speed, she was the most unanimously damned craft that ever came into Boston Harbour.

“Guess that’s a through boat,” remarked an aged salt, facetiously as he gazed at her from a dock. “If that durned fool don’t take some o’ the speed offen her she’ll go through all right — wharf an’ all.”

Still the man in the boat made no motion; the whiz of her motor, plainly heard in a sudden silence, was undiminished. Suddenly the tumult of warning was renewed. Only a chance would prevent a smash. Then Big John Dawson appeared on the string piece of the dock. Big John had a voice that was noted from Newfoundland to Norfolk for its depth and width, and possessed objurgatory powers which were at once the awe and admiration of the fishing fleet.

“You ijit!” he bellowed at the impassive helmsman. “Shut off that power an’ throw yer hellum.”

There was no response; the boat came on directly toward the dock where Big John and his fellows were gathered. The fishermen and loungers saw that a crash was coming and scattered from the string piece.

“The durned fool,” said Big John, resignedly.

Then came the crash, the rending of timbers, and silence save for the grinding whir of the motor. Big John ran to the end of the wharf and peered down. The speed of the motor had driven the boat half way upon a float which careened perilously. The man had been thrown forward and lay huddled up face downward and motionless on the float. The dirty water lapped at him greedily.

Big John was the first man on the float. He crept cautiously to the huddled figure and turned it face upward. He gazed for an instant into wide staring eyes then turned to the curious ones peering down from the dock.

“No wonder he didn’t stop,” he said in an awed tone. “The durned fool is dead.”

Willing hands gave aid and after a minute the lifeless figure lay on the dock. It was that of a man in uniform — the uniform of a foreign navy. He was apparently forty-five years old, large and powerful of frame with the sun-browned face of a seaman. The jet black of moustache and goatee was startling against the dead colour of the face. The hair was tinged with gray; and on the back of the left hand was a single letter —“D”— tattooed in blue.

“He’s French,” said Big John authoritatively, “an’ that’s the uniform of a Cap’n in the French Navy.” He looked puzzled a moment as he stared at the figure. “An’ they ain’t been a French man-o’-war in Boston Harbour for six months.”

After awhile the police came and with them Detective Mallory, the big man of the Bureau of Criminal Investigation; and finally Dr. Clough, Medical Examiner. While the detective questioned the fishermen and those who had witnessed the crash Dr. Clough examined the body.

“An autopsy will be necessary,” he announced as he arose.

“How long has he been dead?” asked the detective.

“Eight or ten hours, I should say. The cause of death doesn’t appear. There is no shot or knife wound so far as I can see.”

Detective Mallory closely examined the dead man’s clothing. There was no name or tailor mark; the linen was new; the name of the maker of the shoes had been ripped out with a knife. There was nothing in the pockets, not a piece of paper or even a vagrant coin.

Then Detective Mallory turned his attention to the boat. Both hull and motor were of French manufacture. Long, deep scratches on each side showed how the name had been removed. Inside the boat the detective saw something white and picked it up. It was a handkerchief — a woman’s handkerchief, with the initials “E. M. B.” in a corner.

“Ah, a woman’s in it!” he soliloquised.

Then the body was removed and carefully secluded from the prying eyes of the press. Thus no picture of the dead man appeared. Hutchinson Hatch, reporter, and others asked many questions.

Detective Mallory hinted vaguely at international questions — the dead man was a French officer, he said, and there might be something back of it.

“I can’t tell you all of it,” he said wisely, “but my theory is complete. It is murder. The victim was captain of a French man-of-war. His body was placed in a motor boat, possibly a part of the fittings of the war ship and the boat set adrift. I can say no more.”

“Your theory is complete then,” Hatch remarked casually, “except the name of the man, the manner of death, the motive, the name of his ship, the presence of the handkerchief and the precise reason why the body should be disposed of in this fashion instead of being cast into the sea?”

The detective snorted. Hatch went away to make some inquiries on his own account. Within half a dozen hours he had satisfied himself by telegraph that no French war craft had been within five hundred miles of Boston for six months. Thus the mystery grew deeper; a thousand questions to which there seemed no answer arose.

At this point, the day following the events related, the problem of the motor boat came to the attention of Professor Augustus S. F. X. Van Dusen, The Thinking Machine. The scientist listened closely but petulantly to the story Hatch told.

“Has there been an autopsy yet?” he asked at last.

“It is set for eleven o’clock today,” replied the reporter. “It is now after ten.”

“I shall attend it,” said the scientist.

Medical Examiner Clough welcomed the eminent Professor Van Dusen’s proffer of assistance in his capacity of M. D., while Hatch and other reporters impatiently cooled their toes on the curb. In two hours the autopsy had been completed. The Thinking Machine amused himself by studying the insignia on the dead man’s uniform, leaving it to Dr. Clough to make a startling statement to the press. The man had not been murdered; he had died of heart failure. There was no poison in the stomach, nor was there a knife or pistol wound.

Then the inquisitive press poured in a flood of questions. Who had scratched off the name of the boat? Dr. Clough didn’t know. Why had it been scratched off? Still he didn’t know. How did it happen that the name of the maker of the shoes had been ripped out? He shrugged his shoulders. What did the handkerchief have to do with it? Really he couldn’t conjecture. Was there any inkling of the dead man’s identity? Not so far as he knew. Any scar on the body which might lead to identification? No.

Hatch made a few mental comments on officials in general and skilfully steered The Thinking Machine away from the other reporters.

“Did that man die of heart failure?” he asked, flatly.

“He did not,” was the curt reply. “It was poison.”

“But the Medical Examiner specifically stated that there was no poison in the stomach,” persisted the reporter.

The scientist did not reply. Hatch struggled with and suppressed a desire to ask more questions. On reaching home the scientist’s first act was to consult an encyclopaedia. After several minutes he turned to the reporter with an inscrutable face.

“Of course the idea of a natural death in this case is absurd,” he said, shortly. “Every fact is against it. Now, Mr. Hatch, please get for me all the local and New York newspapers of the day the body was found — not the day after. Send or bring them to me, then come again at five this afternoon.”

“But — but —” Hatch blurted.

“I can say nothing until I know all the facts,” interrupted The Thinking Machine.

Hatch personally delivered the specified newspapers into the hands of The Thinking Machine — this man who never read newspapers — and went away. It was an afternoon of agony; an agony of impatience. Promptly at five o’clock he was ushered into Professor Van Dusen’s laboratory. He sat half smothered in newspapers, and popped up out of the heap aggressively.

“It was murder, Mr. Hatch,” he exclaimed, suddenly. “Murder by an extraordinary method.”

“Who — who is the man? How was he killed?” asked Hatch.

“His name is —” the scientist began, then paused. “I presume your office has the book ‘Who’s Who In America?’ Please ‘phone and ask them to give you the record of Langham Dudley.”

“Is he the dead man?” Hatch demanded quickly.

“I don’t know,” was the reply.

Hatch went to the telephone. Ten minutes later he returned to find The Thinking Machine dressed to go out.

“Langham Dudley is a ship owner, fifty-one years old,” the reporter read from notes he had taken. “He was once a sailor before the mast and later became a ship owner in a small way. He was successful in his small undertakings and for fifteen years has been a millionaire. He has a certain social position, partly through his wife whom he married a year and a half ago. She was Edith Marston Belding, a daughter of the famous Belding family. He has an estate on the North Shore.”

“Very good,” commented the scientist. “Now we will find out something about how this man was killed.”

At North Station they took train for a small place on the North Shore, thirty five miles from Boston. There The Thinking Machine made some inquiries and finally they entered a lumbersome carry-all. After a drive of half an hour through the dark they saw the lights of what seemed to be a pretentious country place. Somewhere off to the right Hatch heard the roar of the restless ocean.

“Wait for us,” commanded The Thinking Machine as the carry-all stopped.

The Thinking Machine ascended the steps, followed by Hatch, and rang. After a minute or so the door was opened and a light flooded out. Standing before them was a Japanese — a man of indeterminate age with the graven face of his race.

“Is Mr. Dudley in?” asked The Thinking Machine.

“He has not that pleasure,” replied the Japanese, and Hatch smiled at the queerly turned phrase.

“Mrs. Dudley?” asked the scientist.

“Mrs. Dudley is attiring herself in clothing,” replied the Japanese. “If you will be pleased to enter.”

The Thinking Machine handed him a card and was shown into a reception room. The Japanese placed chairs for them with courteous precision and disappeared. After a short pause there was a rustle of silken skirts on the stairs, and a woman — Mrs. Dudley — entered. She was not pretty; she was stunning rather, tall, of superb figure and crowned with a glory of black hair.

“Mr. Van Dusen?” she asked as she glanced at the card.

The Thinking Machine bowed low, albeit awkwardly. Mrs. Dudley sank down on a couch and the two men resumed their seats. There was a little pause; Mrs. Dudley broke the silence at last.

“Well, Mr. Van Dusen, if you —” she began.

“You have not seen a newspaper for several days?” asked The Thinking Machine, abruptly.

“No,” she replied, wonderingly, almost smiling. “Why?”

“Can you tell me just where your husband is?”

The Thinking Machine squinted at her in that aggressive way which was habitual. A quick flush crept into her face; and grew deeper at the sharp scrutiny. Inquiry lay in her eyes.

“I don’t know,” she replied at last. “In Boston, I presume.”

“You haven’t seen him since the night of the ball?”

“No. I think it was half past one o’clock that night.”

“Is his motor boat here?”

“Really, I don’t know. I presume it is. May I ask the purpose of this questioning?”

The Thinking Machine squinted hard at her for half a minute. Hatch was uncomfortable, half resentful even, at the agitation of the woman and the sharp, cold tone of his companion.

“On the night of the ball,” the scientist went on, passing the question, “Mr. Dudley cut his left arm just above the wrist. It was only a slight wound. A piece of court plaster was put on it. Do you know if he put it on himself? If not, who did?”

“I put it on,” replied Mrs. Dudley, unhesitatingly, wonderingly.

“And whose court plaster was it?”

“Mine — some I had in my dressing room. Why?”

The scientist arose and paced across the floor, glancing once out the hall door. Mrs. Dudley looked at Hatch inquiringly and was about to speak when The Thinking Machine stopped beside her and placed his slim fingers on her wrist. She did not resent the action; was only curious if one might judge from her eyes.

“Are you prepared for a shock?” the scientist asked.

“What is it?” she demanded in sudden terror. “This suspense —”

“Your husband is dead — murdered — poisoned!” said the scientist with sudden brutality. His fingers still lay on her pulse. “The court plaster which you put on his arm and which came from your room was covered with a virulent poison which was instantly transfused into his blood.”

Mrs. Dudley did not start or scream. Instead she stared up at The Thinking Machine a moment, her face became pallid, a little shiver passed over her. Then she fell back on the couch in a dead faint.

“Good!” remarked The Thinking Machine complacently. And then as Hatch started up suddenly: “Shut that door,” he commanded.

The reporter did so. When he turned back his companion was leaning over the unconscious woman. After a moment he left her and went to a window where he stood looking out. As Hatch watched he saw the colour coming back into Mrs. Dudley’s face. At last she opened her eyes.

“Don’t get hysterical,” The Thinking Machine directed calmly. “I know you had nothing whatever to do with your husband’s death. I want only a little assistance to find out who killed him.”

“Oh, my God!” exclaimed Mrs. Dudley. “Dead! Dead!”

Suddenly tears leapt from her eyes and for several minutes the two men respected her grief. When at last she raised her face her eyes were red, but there was a rigid expression about the mouth.

“If I can be of any service —” she began.

“Is this the boat house I see from this window?” asked The Thinking Machine. “That long, low building with the light over the door?”

“Yes,” replied Mrs. Dudley.
............