The warden spent an hour wondering what sort of a cipher it was, and half an hour wondering why his prisoner should attempt to communicate with Dr. Ransome, who was the cause of him being there. After this the warden devoted some thought to the question of where the prisoner got writing materials, and what sort of writing materials he had. With the idea of illuminating this point, he examined the linen again. It was a torn part of a white shirt and had ragged edges.
Now it was possible to account for the linen, but what the prisoner had used to write with was another matter. The warden knew it would have been impossible for him to have either pen or pencil, and, besides, neither pen nor pencil had been used in this writing. What, then? The warden decided to personally investigate. The Thinking Machine was his prisoner; he had orders to hold his prisoners; if this one sought to escape by sending cipher messages to persons outside, he would stop it, as he would have stopped it in the case of any other prisoner.
The warden went back to Cell 13 and found The Thinking Machine on his hands and knees on the floor, engaged in nothing more alarming than catching rats. The prisoner heard the warden's step and turned to him quickly.
"It's disgraceful," he snapped, "these rats. There are scores of them."
"Other men have been able to stand them," said the warden. "Here is another shirt for you-let me have the one you have on."
"Why?" demanded The Thinking Machine, quickly. His tone was hardly natural, his manner suggested actual perturbation.
"You have attempted to communicate with Dr. Ransome," said the warden severely. "As my prisoner, it is my duty to put a stop to it."
The Thinking Machine was silent for a moment.
"All right," he said, finally. "Do your duty."
The warden smiled grimly. The prisoner arose from the floor and removed the white shirt, putting on instead a striped convict shirt the warden had brought. The warden took the white shirt eagerly, and then and there compared the pieces of linen on which was written the cipher with certain torn places in the shirt. The Thinking Machine looked on curiously.
"The guard brought you those, then?" he asked.
"He certainly did," replied the warden triumphantly. "And that ends your first attempt to escape."
The Thinking Machine watched the warden as he, by comparison, established to his own satisfaction that only two pieces of linen had been torn from the white shirt.
"What did you write this with?" demanded the warden.
"I should think it a part of your duty to find out," said The Thinking Machine, irritably.
The warden started to say some harsh things, then restrained himself and made a minute search of the cell and of the prisoner instead. He found absolutely nothing; not even a match or toothpick which might have been used for a pen. The same mystery surrounded the fluid with which the cipher had been written. Although the warden left Cell 13 visibly annoyed, he took the torn shirt in triumph.
"Well, writing notes on a shirt won't get him out, that's certain," he told himself with some complacency. He put the linen scraps into his desk to await developments. "If that man escapes from that cell I'll-hang it-I'll resign."
On the third day of his incarceration The Thinking Machine openly attempted to bribe his way out. The jailer had brought his dinner and was leaning against the barred door, waiting, when The Thinking Machine began the conversation.
"The drainage pipes of the prison lead to the river, don't they?" he asked.
"Yes," said the jailer.
"I suppose they are very small?"
"Too small to crawl through, if that's what you're thinking about," was the grinning response.
There was silence until The Thinking Machine finished his meal. Then: "You know I'm not a criminal, don't you?"
"And that I've a perfect right to be freed if I demand it?"
"Well, I came here believing that I could make my escape," said the prisoner, and his squint eyes studied the face of the jailer. "Would you consider a financial reward for aiding me to escape?"
The jailer, who happened to be an honest man, looked at the slender, weak figure of the prisoner, at the large head with its mass of yellow hair, and was almost sorry.
"I guess prisons like these were not built for the likes of you to get out of," he said, at last.
"But would you consider a proposition to help me get out?" the prisoner insisted, almost beseechingly.
"No," said the jailer, shortly.
"Five hundred dollars," urged The Thinking Machine. "I am not a, criminal."
"No," said the jailer.
"No," again said the jailer, and he started away hurriedly to escape further temptation. Then he turned back. "If you should give me ten thousand dollars I couldn't get you out. You'd have to pass through seven doors, and I only have the keys to two."
Then he told the warden all about it.
"Plan number two fails," said the warden, smiling grimly. "First a cipher, then bribery."
When the jailer was on his way to Cell 13 at six o'clock, again bearing food to The Thinking Machine, he paused, startled by the unmistakable scrape, scrape of steel against steel. It stopped at the sound of his steps, then craftily the jailer, who was beyond the prisoner's range of vision, resumed his tramping, the sound being apparently that of a man going away from Cell 13. As a matter of fact he was in the same spot.
After a moment there came again the steady scrape, scrape, and the jailer crept cautiously on tiptoes to the door and peered between the bars. The Thinking Machine was standing on the iron bed working at the bars of the little window. He was using a file, judging from the backward and forward swing of his arms.
Cautiously the jailer crept back to the office, summoned the warden in person, and they returned to Cell 13 on tiptoes. The steady scrape was still audible. The warden listened to satisfy himself and then suddenly appeared at the door.
"Well?" he demanded, and there was a smile on his face.
The Thinking Machine glanced back from his perch on the bed and leaped suddenly to the floor, making frantic efforts to hide something. The warden went in, with hand extended.
"Give it up," he said.
"No," said the prisoner, sharply.
"Come, give it up," urged the warden. "I don't want to have to search you again."
"No," repeated the prisoner.
"What was it, a file?" asked the warden.
The Thinking Machine was silent and stood squinting at the warden with something very nearly approaching disappointment on his face-nearly, but not quite. The warden was almost sympathetic.
"Plan number three fails, eh?" he asked, good-naturedly. "Too bad, isn't it?"
The prisoner didn't say.
"Search him," instructed the warden.
The jailer searched the prisoner carefully. At last, artfully concealed in the waistband of the trousers, he found a piece of steel about two inches long, with one side curved like a half moon.
"Ah," said the warden, as he received it from the jailer. "From your shoe heel," and he smiled pleasantly.
The jailer continued his search and on the other side of the trousers waistband found another piece of steel identical with the first. The edges showed where they had been worn against the bars of the window.
"You couldn't saw a way through those bars with these," said the warden.
"I could have," said The Thinking Machine firmly.
"In six months, perhaps," said the warden, good-naturedly.
The warden shook his head slowly as he gazed into the slightly flushed face of his prisoner.
"Ready to give it up?" he asked.
"I haven't started yet," was the prompt reply.
Then came another exhaustive search of the cell. Carefully the two men went over it, finally turning out the bed and searching that. Nothing. The warden in person climbed upon the bed and examined the bars of the window where the prisoner had been sawing. When he looked he was amused.
"Just made it a little bright by hard rubbing," he said to the prisoner, who stood looking on with a somewhat crestfallen air. The warden grasped the iron bars in his strong hands and tried to shake them. They were immovable, set firmly in the solid granite. He examined each in turn and found them all satisfactory. Finally he climbed down from the bed.
"Give it up, professor," he advised.
The Thinking Machine shook his head and the warden and jailer passed on again. As they disappeared down the corridor The Thinking Machine sat on the edge of the bed with his head in his hands.
"He's crazy to try to get out," said the warden. "But he's clever. I would like to know what he wrote that cipher with."
It was four o'clock next morning when an awful, heart-racking shriek of terror resounded through the great prison. It came from a cell, somewhere about the centre, and its tone told a tale of horror, agony, terrible fear. The warden heard and with three of his men rushed into the long corridor leading to Cell 13.