"From the moment the rat disappeared into that dusty pipe I became anxious. I was taking so many chances. The rat might gnaw the string, of which I held one end; other rats might gnaw it; the rat might run out of the pipe and leave the linen and money where they would never be found; a thousand other things might have happened. So began some nervous hours, but the fact that the rat ran on until only a few feet of the string remained in my cell made me think he was outside the pipe. I had carefully instructed Mr. Hatch what to do in case the note reached him. The question was: Would it reach him?
"This done, I could only wait and make other plans in case this one failed. I openly attempted to bribe my jailer, and learned from him that he held the keys to only two of seven doors between me and freedom. Then I did something else to make the warden nervous. I took the steel supports out of the heels of my shoes and made a pretense of sawing the bars of my cell window. The warden raised a pretty row about that. He developed, too, the habit of shaking the bars of my cell window to see if they were solid. They were — then."
Again the warden grinned. He had ceased being astonished.
"With this one plan I had done all I could and could only wait to see what happened," the scientist went on. "I couldn't know whether my note had been delivered or even found, or whether the rat had gnawed it up. And I didn't dare to draw back through the pipe that one slender thread which connected me with the outside.
"When I went to bed that night I didn't sleep, for fear there would come the slight signal twitch at the thread which was to tell me that Mr. Hatch had received the note. At half-past three o'clock, I judge, I felt this twitch, and no prisoner actually under sentence of death ever welcomed a thing more heartily."
The Thinking Machine stopped and turned to the reporter.
"You'd better explain just what you did," he said.
"The linen note was brought to me by a small boy who had been playing baseball," said Mr. Hatch. "I immediately saw a big story in it, so I gave the boy another ten dollars, and got several spools of silk, some twine, and a roll of light, pliable wire. The professor's note suggested that I have the finder of the note show me just where it was picked up, and told me to make my search from there, beginning at two o'clock in the morning. If I found the other end of the thread I was to twitch it gently three times, then a fourth.
"I began the search with a small bulb electric light. It was an hour and twenty minutes before I found the end of the drain pipe, half hidden in weeds. The pipe was very large there, say twelve inches across. Then I found the end of the lisle thread, twitched it as directed and immediately I got an answering twitch.
"Then I fastened the silk to this and Professor Van Dusen began to pull it into his cell. I nearly had heart disease for fear the string would break. To the end of the silk I fastened the twine, and when that had been pulled in, I tied on the wire. Then that was drawn into the pipe and we had a substantial line, which rats couldn't gnaw, from the mouth of the drain into the cell."
The Thinking Machine raised his hand and Hatch stopped.
"All this was done in absolute silence," said the scientist. "But when the wire reached my hand I could have shouted. Then we tried another experiment, which Mr. Hatch was prepared for. I tested the pipe as a speaking tube. Neither of us could hear very clearly, but I dared not speak loud for fear of attracting attention in the prison. At last I made him understand what I wanted immediately. He seemed to have great difficulty in understanding when I asked for nitric acid, and I repeated the word 'acid' several times.
"Then I heard a shriek from a cell above me. I knew instantly that some one had overheard, and when I heard you coming, Mr. Warden, I feigned sleep. If you had entered my cell at that moment that whole plan of escape would have ended there. But you passed on. That was the nearest I ever came to being caught.
"Having established this improvised trolley it is easy to see how I got things in the cell and made them disappear at will. I merely dropped them back into the pipe. You, Mr. Warden, could not have reached the connecting wire with your fingers; they are too large. My fingers, you see, are longer and more slender. In addition I guarded the top of that pipe with a rat — you remember how."
"I remember," said the warden, with a grimace.
"I thought that if any one were tempted to investigate that hole the rat would dampen his ardor. Mr. Hatch could not send me anything useful through the pipe until next night, although he did send me change for ten dollars as a test, so I proceeded with other parts of my plan. Then I evolved the method of escape, which I finally employed.
"In order to carry this out successfully it was necessary for the guard in the yard to get accustomed to seeing me at the cell window. I arranged this by dropping linen notes to him, boastful in tone, to make the warden believe, if possible, one of his assistants was communicating with the outside for me. I would stand at my window for hours gazing out, so the guard could see, and occasionally I spoke to him. In that way I learned that the prison had no electricians of its own, but was dependent upon the lighting company if anything should go wrong.
"That cleared the way to freedom perfectly. Early in the evening of the last day of my imprisonment, when it was dark, I planned to cut the feed wire which was only a few feet from my window, reaching it with an acid-tipped wire I had. That would make that side of the prison perfectly dark while the electricians were searching for the break. That would also bring Mr. Hatch into the prison yard.
"There was only one more thing to do before I actually began the work of setting myself free. This was to arrange final details with Mr. Hatch through our speaking tube. I did this within half an hour after the warden left my cell on the fourth night of my imprisonment. Mr. Hatch again had serious difficulty in understanding me, and I repeated the word 'acid' to him several times, and later the words: 'Number eight hat' — that's my size — and these were the things which made a prisoner upstairs confess to murder, so one of the jailers told me next day. This prisoner heard our voices, confused of course, through the pipe, which also went to his cell. The cell directly over me was not occupied, hence no one else heard.
"Of course the actual work of cutting the steel bars out of the window and door was comparatively easy with nitric acid, which I got through the pipe in thin bottles, but it took time. Hour after hour on the fifth and sixth and seven days the guard below was looking at me as I worked on the bars of the window with the acid on a piece of wire. I used the tooth powder to prevent the acid spreading. I looked away abstractedly as I worked and each minute the acid cut deeper into the metal. I noticed that the jailers always tried the door by shaking the upper part, never the lower bars, therefore I cut the lower bars, leaving them hanging in place by thin strips of metal. But that was a bit of dare-deviltry. I could not have gone that way so easily."
The Thinking Machine sat silent for several minutes.
"I think that makes everything clear," he went on. "Whatever points I have not explained were merely to confuse the warden and jailers. These things in my bed I brought in to please Mr. Hatch, who wanted to improve the story. Of course, the wig was necessary in my plan. The special delivery letter I wrote and directed in my cell with Mr. Hatch's fountain pen, then sent it out to him and he mailed it. That's all, I think."
"But your actually leaving the prison grounds and then coming in through the outer gate to my office?" asked the warden.
"Perfectly simple," said the scientist. "I cut the electric light wire with acid, as I said, when the current was off. Therefore when the current was turned on, the arc light didn't light. I knew it would take some time to find out what was the matter and make repairs. When the guard went to report to you the yard was dark. I crept out the window — it was a tight fit, too — replaced the bars by standing on a narrow ledge and remained in a shadow until the force of electricians arrived. Mr. Hatch was one of them.