"We have not informed the emperor of the affair as yet," he said, at last, steadily. "We thought it inadvisable to go so far until every effort had been made to--"
The Thinking Machine interrupted him with an impatient gesture of one slender hand.
"As a matter of fact, the situation is like this, isn't it?" he queried abruptly. "Prince Otto Ludwig, heir apparent to the throne of Germania-Austria, has been abducted from the royal suite of the battleship Friedrich der Grosse, in the harbor of a friendly nation?"
There was an instant's amazed silence. Suddenly Admiral Hausen-Aubier covered his face with his hands, and stood, his great shoulders shaking. Straining nerves had broken at last. Baron Von Hartzfeldt, ripe in diplomatic experience, seemed merely astonished, if one might judge by the face of him.
"How do you know that?" he inquired quietly, after a moment. "Outside of the secret service and my own agents, there are not six persons in the world who are aware--"
"How do I know it?" interrupted The Thinking Machine. "You have just told me. Logic, logic, logic!"
"I have told you?" There was blank bewilderment on the diplomatist's face.
"You and Admiral Hausen-Aubier together," The Thinking Machine declared petulantly.
"But how, man, how?" demanded Baron Von Hartzfeldt. "Of course, you knew from the newspapers that his highness, Crown Prince Otto Ludwig, was visiting America; but--"
"I never read newspapers," snapped The Thinking Machine. "I didn't know he was here any more than I knew the battleship Friedrich der Grosse was in the harbor. It's logic, logic-the adding together of the separate units-a simple demonstration of the fact that two and two make four, not sometimes, but all the time."
Admiral Hausen-Aubier, having mastered the emotion which had shaken him, resumed his seat, staring curiously into the wizened face before him.
"Still I don't understand," Baron Von Hartzfeldt insisted. "Logic, you say. How?"
"I'll see if I can make it clear." And there was that in the manner of the eminent man of science which was no compliment to their perspicacity. "You tell me an officer has disappeared, that his guard was chloroformed. The officer was not under arrest, and no other officer aboard ship had a guard. I assume, therefore, for the moment that the officer was a man of consequence, else he was mentally irresponsible. An instant later you tell me how to enter the officer's suite-not stateroom, but suite. Ergo, a man of so much consequence that he occupies a suite; a man of so much consequence that you didn't dare report his disappearance to the police; a man of so much consequence that public knowledge of the affair would precipitate disaster. Do you follow the thread?"
Fascinated, the two listeners nodded.
"Very well," The Thinking Machine resumed, in that odd little tone of irritation. "There are only a few persons in the world of so much consequence as all that-that is, of so much consequence aboard a ship of war. Those are members of the royal household. I am of German descent; hence I am well acquainted with the histories of the German countries. I know that Emperor Gustavus has only one son, Otto Ludwig, the crown prince. I know that no reigning king has ever visited America; therefore logic, inexorable, indisputable logic, tells me that Prince Otto Ludwig is the officer who occupied the royal suite aboard your ship."
He paused, and readjusted himself in the great chair. When he spoke again, it was in the tone of one who is thoughtfully checking off and verifying the units of a problem he has solved. His two visitors were staring at him breathlessly.
"Of course, no royal person save a son of the house of Germania-Austria would be occupying the royal suite on a Germania-Austrian battleship," he said slowly. "Proper adjustment of the actual facts leading straight to the crown prince removed instantly as a possibility a vague suggestion that the officer with the guard at his door, while not a prisoner, was mentally irresponsible. I've made myself clear, I hope?"
"It's marvelous!" ejaculated the diplomatist. "If any man can lead us to the end of this mystery, you are that man!"
"Thanks," returned The Thinking Machine dryly.
"You said," Admiral Hausen-Aubier questioned tensely, "that his highness had been abducted?"
"Certainly."
"Why abducted instead of-of-murdered--" He shuddered a little. "Instead of suicide?"
"That man who is clever enough and bold enough to board your ship and chloroform a guard is not fool enough to murder a man and then drag him out over the guard and throw him into the sea," was the reply, "or to drag him out and then murder him. In either event, such an act would have been useless; and as a rule murderers don't do useless things. As for suicide, it would not have been necessary for the prince to chloroform his guard, or even to leave his stateroom. Remains, therefore, only abduction."
"But who abducted him?" the admiral insisted. "Why? How was he taken away from the ship?"
The Thinking Machine shrugged his narrow shoulders.
"I don't know," he said. "Either one of a dozen ways-aeroplane, rowboat, submarine--" He stopped.
"But-but no one heard anything," the admiral pointed out.
"That doesn't signify."
There seemed nothing to cling to, no tangible fact upon which to base even understanding. Aeroplane-submarine-'twas fantasy, preposterous, unheard of. Hopelessly enough, Admiral Hausen-Aubier turned back to the one vital question:
"At any rate, the prince is alive?"
"I don't know. He was abducted a week ago. You've heard nothing since. He may have been murdered after he was taken away. He may have been. I doubt it."
Admiral Hausen-Aubier arose tragically, with haggard face, a light of desperation in his eyes, his powerful, sun-dyed hands pressed to his temples.
"If he is dead, do you know what it means?" he demanded vehemently. "It means the fall of the royal house of Germania-Austria with the passing of our emperor, who is now nearly eighty; it means the end of our country as a monarchy; it means war, revolution, a-a republic!"
"That wouldn't be so bad," commented The Thinking Machine oddly. "There'll be nothing but republics in a few years; witness France, Portugal, China--"
"You can't realize the acute political situation in my country," Admiral Hausen-Aubier rushed on, heedless of the other's remark. "Already there are dissensions; the emperor holds his kingdom together with a rod of iron, and his people only submit because they expect so much of Prince Otto Ludwig when he ascends the throne. He is popular with his subjects-the crown prince, I mean-and they would welcome him as emperor-welcome him, but no one else. It is absolutely necessary that he be found! The future of my country-our country," and he turned to Baron Von Hartzfeldt, "depends upon finding him."
Seemingly some new thought was born in The Thinking Machine's mind. His eyes opened slightly, and he turned upon Baron Von Hartzfeldt inquiringly. Apparently the ambassador understood, for he nodded.
"He is revealing diplomatic secrets," he said, with a slight movement of his shoulders; "but what he says is true."
"In that case--" The Thinking Machine began; and then he lapsed into silence. For minute after minute he sat, heedless of the nervous pacing of Admiral Hausen-Aubier, heedless of the constant interrogation of the ambassador's eyes.
"In that case--" the ambassador prompted.
"Is Crown Prince Otto Ludwig here incognito, or is it generally known that he is in this country?" the scientist questioned suddenly.
"He is here officially," was the response; "that is, publicly. The government of the United States has received him and entertained him, and you know all that that means."
"Then how do you-have you-accounted for his disappearance?"
"Lies!" Admiral Hausen-Aubier broke in bitterly. "He is supposed to be dangerously ill, confined to his stateroom aboard the Friedrich der Grosse; and no one except the ship's surgeon is permitted to see him. We have lied even to our emperor! He believes the prince is ill; if he understood that his son, the heir apparent, was missing, dead, perhaps-ach, Gott! Every moment I am expecting sailing orders-orders to return home. I can't go back to my king and tell him that the son he intrusted to my care, the hope and salvation of my country, is-is-I can't even say dead-I could only say that I don't know."
There was something magnificent in the bronzed old sailorman-something at once rugged and tender and fierce in his loyalty. The Thinking Machine studied the grief-stricken face curiously. Unashamed, Admiral Hausen-Aubier permitted the tears to gather in his eyes and roll down his furrowed cheeks.
"I don't care for myself," he explained huskily. "I do care for my country, for my prince. In any event, there remains for me only dishonor and death."
"Suicide?" questioned the scientist coldly.
"What else is there?"
"That," The Thinking Machine murmured acridly, "would improve the situation a lot! If I had committed suicide every time I had a problem to solve I should have been very dead by this time." His manner changed. "We know the prince was abducted; he is probably not dead, but we have no word of him or from him; therefore, there remains only--"
"Only what?" The question came from his two visitors simultaneously.
"Only a question of the most effective way of establishing communication with him."