"I don't know if Dr. Maher even knows just why I ordered Tennell under arrest," continued the Captain. "Miss Bellingdame's story decided me. She was going to the wireless office to send a message, when she saw a man-it was First Officer Tennell-thrust his head out the door and look around, as if he contemplated escape. She thought it rather curious that he should slam the door when he saw her; but it meant nothing particularly. Then, at a time when we now know Ingraham was dead, she carried on a conversation with some one in the wireless office, through the locked door. Tennell had not mentioned this to me, and coming as it did it seemed so conclusive that I ordered his arrest."
"It was conclusive from the first," remarked Dr. Maher.
"And then hearing the wireless that night after I had taken pains to assure myself that there was no operator aboard!" Captain Deihl resumed, and his face reflected his bewilderment. "I went straight from the bridge to the wireless office, to find it silent, dark, and the door locked. I called. There was no answer, and I smashed in the door. There was no sign of anyone having been in there-everything was precisely as we left it when the body was removed."
For a long time there was silence. Dr. Maher drummed impatiently on the arm of his chair; The Thinking Machine sat motionless, his slender figure all but engulfed in the huge chair.
"As I understand it," remarked The Thinking Machine at last, "Tennell is now in the hands of the police, and the body is--"
"Ashore awaiting burial," the Captain supplied. "Miss Bellingdame has asked permission of the authorities to take charge of it."
Dr. Maher arose and went to the window, where he stood looking out. The Thinking Machine lowered his squint eyes and stared steadily at the ship's surgeon.
"The case against the first officer seems perfectly clear thus far," said the scientist after a pause. "Why do you come to me?"
Captain Deihl's bronzed face reddened as if he was embarrassed, and he cleared his throat. "Because I know Harry Tennell," he said bluntly. "Circumstances are compelling me to believe that he is a murderer, and my reason won't let me believe it. Why, man, I've known him for years, and I simply can't make myself believe what I have to believe! The police are deaf to the bare suggestion of his innocence, and I-I came here."
"All of which is rather to the credit of your heart than to your head," interposed Dr. Maher cynically.
"Have you any cause to suspect anyone but Tennell, Captain?" inquired The Thinking Machine. He was squinting at the back of Dr. Maher's head. "Can you imagine any other motive than the apparent one?"
"No," replied Captain Deihl. "I can imagine nothing; but I would gamble my right arm that Harry Tennell didn't kill him."
Again there was silence. The Captain was gazing vainly into the drawn, inscrutable face of the diminutive scientist, who lay back with finger tips pressed together and eyes turned steadily upward.
"Dr. Maher," inquired the scientist at last, "the wound was made by a knife. Was it clean cut?"
"Yes."
"Was the knife driven to the hilt?"
"Yes. It required considerable strength."
"And I believe Captain Deihl says there was a thin trickle of blood from the wound before you pulled the knife out?"
"That's correct," was the short answer.
"Therefore is a point for Tennell, as it shows the knife had been withdrawn and replaced. And so the real problem is to find what message Ingraham was sending when he was murdered," said the scientist quietly. "Neither of you happens to know?"
"The same thought came to me while Captain Deihl was talking to Tennell," said Dr. Maher quickly. "It was shortly after seven bells in the afternoon-that is, half-past three o'clock-when the crime was discovered. Now, the last message to be sent, according to the time check on it, was sent shortly after twelve. Yet, if we believe Tennell, the operator was sending a message just before he was struck down, or possibly at that moment. Well, there was nothing to show for that message-no scrap of paper-nothing."
The Thinking Machine glanced at Dr. Maher as if surprised. "Therefore the message Ingraham was sending," he put in, "was either stolen or was being composed as he sent it. Is that clear?"
There was a pause. Captain Deihl nodded, and Dr. Maher began drumming on the window sill.
"That being true," the scientist went on incisively, "the next step is to learn who aboard the Uranus could read the code-the Continental code too, mind you, not the Morse-as a message was being sent. Is that clear?"
"Yes; go on," said Captain Deihl.
"When we find the person who could read the Continental code, we also find the person who in all probability was operating the wireless at one o'clock the night of the murder. Is that clear?"
"Yes, yes."
"And when we find the person who operated the wireless logic shows us, incontrovertibly, that we have either the murderer of Ingraham, or some one who was in the plot. Remember, the ship had been canvassed in a search for an operator. None came forward; therefore we know that the operator-an operator-was aboard, but for divers reasons preferred to remain unknown. We know that as certainly as that two and two make four, not sometimes but all the time."
Dr. Maher turned and dropped back into his chair, with a new interest evident in every line of his face.
"With these facts in hand it is a simple matter, albeit perhaps a tedious one, to find what message was sent from the ship both by the operator and by the unknown at night," The Thinking Machine resumed. He was silent for a moment, then arose and left the room. He was gone for perhaps ten minutes. "Now, Captain Deihl, and you, Dr. Maher, have you formed any opinion as to the exact method of the murder? Was the murderer inside the cabin with Ingraham, or was he killed by a knife thrust through an open window? You know the arrangement of the place better than I. What is your opinion?"
Captain Deihl considered the matter carefully as he sought to recall every minute detail of the cabin as he found it. "Since you have brought up the question," he said slowly at last, "it seems to me that he must have been stabbed by some one outside, through the window. His left side was toward the window, and the window was open, as it was warm, and he was in his shirt sleeves. Yes, it was within easy reach, and I'm inclined to believe-- What do you think, Maher?"
"I agree with you perfectly," was the prompt response. "The angle of the knife indicates that an arm had been dropped inside the state room, and there was an upward thrust, where if a person had been in the room the natural angle would have been downward, unless that person had been lying on the floor."
"All of which being true, is a point in favour of Tennell," said The Thinking Machine curtly. "You found him inside the cabin with the body, and we must suppose from your own statement, Dr. Maher, that he would have had to lie down to inflict the wound. I may say that the strongest point in his favour is the fact that he did not throw away the knife. He knew it to be his; had opportunity to get rid of it, but didn't; therefore--" He shrugged his shoulders and was silent for a moment.
"All things depend upon the point of view, gentlemen," he continued after a time. "There are half a dozen casual facts, several of which I have specified, which incline me to a belief in Tennell's innocence; and only two against him, these being the motive and the knife. Strong, you say? Yes; but the knife is turned in his favour. Now let us assume Tennell's innocence for a moment, and build our hypothesis on facts that we know. It is always possible to reconstruct a happening by the logic of its units. Let us see this rule applied to this case.
"We are reasonably certain that whatever message Ingraham was sending just before, or at the moment of his death, was not a written message. I have your word, Dr. Maher, that there was not a trace of any message after the one about noon. Shall we suppose that there was a written message and it was stolen from his desk by the hand that slew? Hardly. Let us take the simple view first. He was sending a message somewhere as he composed it. Now, anyone aboard that ship who knew the Continental code could have read that message, because the wireless has that fault. That being true, we shall admit that somebody did read it, or was reading it as it went.
"Right here we come to what may prove to be the solution. It was necessary for the person who read the message to stop it, and perhaps to silence the man who sent it, even at the cost of a life. Therefore, the importance of the message to the person who read it was life and death. A blow was struck; the message was stopped. But the knife? Tennell says he lost it; anyone might have found it.
"The message is stopped; the man is dead. The next vital necessity which the murderer feels is self protection. How? Can a message be sent which will counteract the one which was stopped by the murder? If this can be done, it is vitally necessary. Some one then-the murderer-takes another tremendous chance, enters the office, and is sending another message, possibly a continuation of the interrupted message, when Captain Deihl becomes aware of it. He goes to investigate, and the probabilities are that the unknown operator escapes by way of the window and regains a state room unobserved.
"That's clear, isn't it? Well, now, what possible motive might lie back of it all? Well, one for instance. Suppose the English police, after the Uranus sailed, had reason to suspect there was some person aboard who as wanted there; they could have reached the Uranus by wireless. But no such report reached the Uranus, you say, Captain? That is, no such report reached you, you mean. The operator might have received such a report; but for reasons of his own kept it to himself. Do you see?
"Let us conjecture a bit. What if a big reward was offered for some person aboard the Uranus, and a statement of the fact reached it by wireless? What if the operator was that peculiar type of man who would hold that information to himself on the chance of discovering and delivering over that person who was wanted to the police of this country, thus holding the reward all to himself? Do you see the possibilities? Now, what if that person who was wanted was an operator as well, and able to read the unwritten message the regular operator was sending,-a message, understand, which meant capture and punishment,-is that a motive for murder?
"This is all partly conjectures, partly fact-merely a discussion of the possibilities. Still, our murderer is unknown. As I have said, the capture of the guilty person may be simple; but it may be tedious. When I hear from--"
There was a sharp, ringing of the telephone bell in the next room. The scientist arose abruptly and went out. After a few minutes he returned.
"You allowed Miss Bellingdarne to leave the Uranus on a motor boat, I understand, before you docked?" he inquired placidly.
"Yes," replied Captain Deihl. "She requested it, and Dr. Maher suggested that it would perhaps be best as she was very ill and weak from the shock following the tragedy."
"I shall be able to put my conjectures to a test at once then," said The Thinking Machine as he put on his hat. "First, I must ask some questions of Miss Bellingdame, however. Suppose you gentlemen wait for me at police headquarters? I shall be there in an hour or so."
The Thinking Machine and Hutchinson Hatch, reporter, were sitting together in a small reception room adjoining the telegraph office in the Hotel Teutonic. Opposite them was Miss Bellingdame, still pale and weary looking, with traces of grief on her face.
"Our close relationship with Mr. Igraham prompted us to call upon you and offer our condolences at this time," The Thinking Machine was saying glibly; "and at the same time to ask if we could be of any service to you?"
"I appreciate the feeling, but hardly think there is anything you can do," Miss Bellingdame responded, "unless, indeed, it is to relieve me of the painful task of taking charge of the body, and--"
"Just what I was going to suggest," interrupted the little scientist. "With your permission I shall send a telegram at once to friends at home and tell them to make preparations. If you will excuse me?" And he arose.
Miss Bellingdame nodded, and he went to the small window of the telegraph office, wrote a despatch, and handed it in. After a moment he resumed his seat.
"It is singular that Charlie should never have mentioned your name in his letters home," continued The Thinking Machine as he dropped back into his chair.