"Then, although it was midnight, I came straight here, aroused Caroline and Miss Jerrod and told them both what had happened so far as I knew. There seemed to be nothing else to do but hide; I did it. I remained here, as I thought safely enough. Two or three reporters came and asked questions, and once a detective was here, but Miss Jerrod answered their inquiries satisfactorily and that seemed to be all-until now. To-morrow Caroline and I were going back to Vermont."
There was a long pause. Caroline pressed the hand of the man she loved to her cheek with a gesture of infinite confidence. The Thinking Machine sat silent with the tips of his long, slender fingers together.
"Mr. Cunningham," he said at last, "you have not told us the one vital thing. Did you or did you not kill Fred Boyd?"
"I don't know," was the reply. "If I only could know!"
"Uh," grunted The Thinking Machine. "I was afraid you wouldn't know."
VI.
Hutchinson Hatch and Manning, the other reporter, gazed at Cunningham thunderstruck, and from him to The Thinking Machine.
"Don't know whether or not you killed a man?" asked Hatch incredulously.
"It's perfectly possible, Mr. Hatch," said The Thinking Machine, curtly. "I understand, Mr. Cunningham," he explained. "I suppose you would be perfectly willing to go with me now?"
"No, no, no," exclaimed Caroline Pierce suddenly, in evident terror.
"Not to the police, Miss Pierce," said The Thinking Machine. He paused a moment and looked at the girl curiously. Of women he knew nothing, and knew he knew nothing. "Perhaps it would assure you, Miss Pierce, if I told you I know that Mr. Cunningham did not kill Boyd."
"You believe he didn't, then?" she asked eagerly.
"I know he didn't," said The Thinking Machine tersely. "Two and two make four not some times, but all the time," he went on enigmatically. "If Mr. Cunningham will come with me now we will establish beyond all doubt the cause of Boyd's death. Do you believe me?"
"Yes," said the girl slowly, and she looked steadily into the squint eyes of the scientist. "I-I have faith in you."
The Thinking Machine coughed, slightly embarrassed, and turned to Hatch with a faint color in his cheeks.
"Well, who did kill Boyd?" asked Hatch, amazed.
"That's what we will now demonstrate," was the reply. "Come on."
After Cunningham had himself assured the girl of his safety the four men passed out into the night-it was nearly 10 o'clock-entered a cab and were driven to the tenement in South Boston. There they passed up the one flight of stairs into the room where Boyd had been found, and after lighting the gas the scientist made one quick survey of the room.
"These walls are awfully thin," he commented petulantly. "If I should fire a pistol in here I might kill someone in another room. Yes, a knife would do better. Have any of you gentlemen a knife-one with a blade that won't break easily?"
"Will this do?" asked Cunningham, and he produced one.
The Thinking Machine examined it and nodded his satisfaction.
"Now a revolver," he said.
Manning went out to get one. While he was gone The Thinking Machine gave some formal instructions to Cunningham and Hatch.
"I'm going to put out this light and remain in this room alone," he said. "I may be here fifteen minutes or I may be here till daylight. I don't know. But I want you three to remain quietly outside the door and listen. When I need you I shall need you quickly. My life may be in danger, and I am not a strong man."
"What is it anyway?" asked Hatch curiously.
"After awhile you will hear something inside, I have no doubt," went on the scientist, paying no attention to the question. "But don't enter the room under any circumstances until I call out or you hear a struggle."
"But what is it?" asked Hatch again. "I don't understand at all."
"I'm going to find the murderer of Fred Boyd," said the scientist. "Please do not ask so many absurd questions. They annoy me exceedingly. I may have to kill him," he added reflectively.
"Kill him?" gasped Hatch. "Who, the murderer?" He couldn't help it.
"Yes, the murderer," was the tart reply.
Manning returned with the revolver, which The Thinking Machine examined and handed to Hatch.
"You will know what to do with it when you enter the room," he instructed. "You, Manning, come in with these other two and light this gas. Keep your matches in your hand."
Then the two reporters and Cunningham passed out of the room, closing the door, but not fastening it. Pressed close against the panels outside, listening, Hatch started to explain to Manning in a whisper when they heard the irritated voice of the scientist.
"Keep silent," was the sharp command.
Five minutes, ten minutes, half an hour of utter silence, save for a distant sound of some sort in the big tenement. But no one came up the stairs. The dim gas light fluttered weirdly down the hall.
A full hour passed, still nothing. Hatch could hear his heart beat, also he thought the regular breathing of The Thinking Machine. At last there came a slight sound, and Hatch started. The other men heard, too.
It was a faint whispering sound, as of the wind rustling through dead leaves, or the silken swish of skirts or the gasp of a dying man.
Hatch clutched the revolver more firmly and set his teeth hard together. He was going to face something-a deadly, terrible something-and had not the faintest idea of what it might be. Manning held a match ready for instant use.
Then, as they listened, there was another sound, still faint, as of something sliding over the floor. Suddenly there was a heavy thump, a half-strangled cry from The Thinking Machine and the sounds of a fearful struggle. Hatch rushed into the room with revolver raised; Manning was just behind him. A match flared up and they saw a struggling heap on the floor. The arm of the scientist rose and fell thrice, burying the knife each time in flesh.
In the light of the gas, which hissed into a brilliant light under the match, the reporter placed the revolver flat against the head of a writhing, twisting body and fired. For the second time he fired, and the struggling bodies lay still.
Then for the first time Hatch realized what had happened. A giant boa constrictor held The Thinking Machine in its coils and was in its death struggle almost crushing the life out of him. It required the combined efforts of the three men to release the scientist from the deadly folds. He lay still for a moment, but finally the life came back into his frail body with a rush. He raised up from Hatch's arms and looked curiously at the snake.
"Dear me, dear me," he commented. "What a brain would have been lost to scientific inquiry if that snake had killed me."
Occupants of the house, aroused by the two pistol shots, rushed again terror-stricken to the room, and after awhile the police came and rescued the four men from the besieging mob of questioners. All went to the police station, and there The Thinking Machine, with several caustic comments on the police in general, told his story. The body of the giant retile lay full length on the floor.
"Mr. Hatch here asked for my advice in the matter," he explained to the police captain, "and I did what I could to assist him. When he explained the condition of the body and the room when it was broken open-the fact the door and both windows were fastened securely inside-it instantly occurred to me that, with suicide removed as a possibility, the thing which had killed Boyd was still in the room or else had escaped only after the body was found.
"It was not unreasonable to suppose that any animal, a snake for instance, would have attempted to leave the room while a crowd of people blocked the door; in fact it was not unreasonable to suppose that such a snake, snuggly fixed in a large, tumble-down building, with the infinite possibility of feeding on rats and mice, would attempt to leave the building at all. It could get water easily from a dozen places.
"Therefore I presumed it was a snake, and I asked Mr. Hatch to ascertain for me first if the people in the house had ever been greatly annoyed by rodents; if they were now, and if not, when they had noticed that they were not. He reported to me that they had been annoyed up to a fortnight preceding the crime, but since they had not noticed. Of course a boa constrictor can live on rodents, therefore they would leave the building or be eaten out of it gradually.
"A fortnight since they missed the rodents? That meant that the snake must have been in the building at least that long. All these conclusion I reached before I personally went over the scene. If it were a snake, as I thought possible, it must have come from somewhere. Where, then?"
The Thinking Machine paused and looked from one to another of his hearers. Each in turn shook his head, Hatch being the last to do so.
"And yet your own paper published a full solution of the mystery before it ever occurred," said the scientist sharply. "Looking from the back window of the room there, perfectly visible, were three banked rings, plainly where a circus had been. Possibly the snake escaped from that circus and crept into the house.
"I called up your office on the 'phone, Mr. Hatch, and ascertained that there had been a circus on that place two weeks before, November 9 and 10, and further I found that a boa constrictor had escaped from that circus. You printed a column of it on the first page."