"He says, sir," she reported, "that he's the ambassador to the United States from Germania-Austria."
"Show him in at once."
Two gentlemen entered, one Baron Von Hartzfeldt, polished, courtly, distinguished in appearance, a famous figure in the diplomatic world; the other of a more rugged type, shorter, heavier, with bristly hair and beard, and deeply bronzed face. For an instant they stared into the wizened countenance of the little scientist with something like astonishment.
"We have come to you, Mr. Van Dusen, in an extremity the gravity of which cannot be exaggerated," Baron Von Hartzfeldt began suavely. "We know, as all the world knows, your splendid achievements in science. We know, too, that you have occasionally consented to investigate more material problems-that is, mysteries of crimes, and--"
"Please come to the point," The Thinking Machine interrupted tartly. "If you hadn't known who I was, and hadn't needed me, you wouldn't have come. Now, what is it? This gentleman--"
"Pardon me," the ambassador begged, in polite confusion at the curt directness of his host. "Admiral Hausen-Aubier, of the royal navy, commanding the Mediterranean Fleet, now visiting your city on his flagship, the Friedrich der Grosse, which lies in the outer harbor."
The admiral bowed ceremoniously, and, accepting a slight movement of The Thinking Machine's hand as an invitation to seats, the two gentlemen sat down. Not until that moment had the scientist realized his own weariness. The big chair offered grateful relaxation to tired limbs, and, with his enormous head tilted back, narrowed eyes turned upward, and slender fingers precisely tip to tip, he waited.
"One of my officers has disappeared from the flagship-rather, has utterly vanished," said Admiral Hausen-Aubier. He spoke excellent English, but there was a guttural undercurrent of excitement in his tone. "He went to his stateroom at midnight; next morning at seven o'clock he was gone. The guard at his door had been drugged with chloroform, and can tell nothing."
"Guard at the door?" questioned The Thinking Machine. "Why?"
Admiral Hausen-Aubier seemed oddly disturbed by the question. He shot a hasty glance at Baron Von Hartzfeldt.
"Ship discipline," explained the diplomat vaguely.
"Was he under arrest?"
"Oh, no!" This from the admiral.
"Do you sleep with a guard at your door?"
"No."
"Any of the other officers?"
"No."
"Go on, please."
"There isn't much to tell." There was bewilderment, deep concern, grief even, in the bronzed face. "The officer's bed had been occupied, but there was no sign of a struggle. It was as if he had arisen, dressed, and gone out. There was no note, no shred or fragment of a clew-nothing. No one saw him from the moment he entered his stateroom and closed his door-not even the guard. There were half a dozen sentries, watchmen, on deck; neither saw nor heard anything out of the ordinary. He isn't aboard ship; we have searched from keel to signal yard; and he didn't go overside in a ship's boat; they are all accounted for. He is not a particularly strong swimmer, and could not have reached shore in that way."
"You say the guard had been chloroformed," The Thinking Machine went back. "Just what happened to him? How do you know he was chloroformed?"
"By the odor," replied the admiral, answering the last question first. "In order to enter the officer's suite it was necessary--"
"Suite, did you say?"
"Yes; that is, he occupied more than one stateroom--"
"I understand. Go on."
"It was necessary to pass through an antechamber. The guard slept there. He says it must have been after one o'clock when he went to sleep. Next morning he was found unconscious, and the officer was gone." He paused. "There can be no question whatever of the guard's integrity. He has been attached to the-the officer for many years."
With eyes all but closed, The Thinking Machine sat motionless for minute after minute, the while thin, spidery lines of though ruffled the domelike brow. At last:
"The matter hasn't been reported to the police?"
"No." Admiral Hausen-Aubier looked startled.
"Why not?"
"Because," Baron Von Hartzfeldt answered, "when it was brought to my attention in Washington by wire, we decided against that. The affair is extremely delicate. It is inadvisable that the police even should so much as suspect--"
The Thinking Machine nodded.
"How about the secret service?"
"That bureau has been at work on the case from the first," the diplomatist replied; "also half a dozen secret agents attached to the embassy. You must understand, Mr. Van Dusen, that it is absolutely essential that no word of the disappearance-not even a hint of it-be allowed to become public. The result would be a-a disaster. I can't say more."
"Perhaps," suggested The Thinking Machine irrelevantly, "perhaps the officer deserted?"
"I would vouch for his loyalty with my life," declared the admiral, with deep feeling.
"Or perhaps it was suicide?"
Again there was a swift interchange of glances between the admiral and the ambassador. Obviously that was a possibility that had occurred to each of them, and yet one that neither dared admit.
"Impossible!" the diplomat shook his head.
"Nothing is impossible," snapped The Thinking Machine curtly. "Don't say that. It annoys me exceedingly." Fell a short silence. Finally: "Just when did your officer disappear?"
"Last Tuesday-almost a week ago," Admiral Hausen-Aubier told him.
"And nothing-nothing-has been heard of him? Or from him? Or from any one else concerning him?"
"Nothing-not a word," Admiral Hausen-Aubier said. "If we could only hear! If we could only know whether he is living or dead!"
"What's his name?"
"Lieutenant Leopold Von Zinckl."
For the first time, The Thinking Machine lowered his eyes and swept the countenances of the two men before him-both grave, troubled, lined with worry. Under his curious scrutiny, the diplomatist retained his self-possession by sheer force of will; but a vital, consuming nervousness seemed to seize upon the man of the sea.
"I mean," and again the scientist was squinting into the gloom above, "I mean his real name."
Admiral Hausen-Aubier's broad face flushed suddenly as if from a blow, and he started to his feet. Some subtle warning form the ambassador caused him to drop back into his seat.
"That is his real name," he said distinctly; "Lieutenant Leopold Von Zinckl."
"May I ask," The Thinking Machine was speaking very slowly, "if his majesty the emperor has been informed of Lieutenant Von Zinckl's disappearance?"
Perhaps The Thinking Machine anticipated the effect of the question; perhaps he did not. Anyway, he didn't look around when Admiral Hausen-Aubier came to his feet with a mighty Teutonic exclamation, and strode the length of the big room, his face dead white beneath the coat of bronze. Baron Von Hartzfeldt remained seated, apparently fascinated by some strange, newly discovered quality in the scientist.