Mr. Tidd put in about a week finishing his turbine and setting it up in the engine-room. We went down to see it when it was all ready. It was to be tried out the next morning. Tucked away in a corner of the engine-room it didn’t look like much. It was little and boxed in so you couldn’t see any of the machine parts that made it go, and somehow didn’t seem very important when you compared it with the big wheels and beams and one thing and another on the engine that stood, all shining with brass, in the middle of the floor. We felt a sort of sinking.

But Mr. Tidd was humming and happy. He patted his little contraption and beamed and beamed. Then he’d look over at the big engine and smile scornful-like. “This here leetle feller,” he said, “will do most as much work as you will, with all your size and brass and roarin’. You want to look out, for this leetle feller is goin’ to be the death of you, and don’t you forget it!”

“Mr. Tidd,” said Mr. Whiteley, “I hope you aren’t too confident. It won’t be too big a disappointment if it fails to work?”

“Fails to work! Why, it will work, Mr. Whiteley. It—”

“But lots of others have failed—men with technical educations, eminent engineers.”

“They didn’t know what I know, Mr. Whiteley. Not what I know. No, sir. The Tidd turbine’s goin’ to do what it ought to. You see.”

We left the engine-room, and Mark went home with his father. The trial was to come off at nine o’clock the next morning, and we were to be there. It was a promise. Nobody was to see it but Mr. Tidd and Mr. Whiteley and us four boys. Of course the engineer would be there, but he didn’t count—or we thought so, anyhow.

Binney and I were on hand before eight o’clock, and we had a whole hour to hang around. It was tiresome waiting by the door, so we got up and prowled around the building just to pass away the time and see what we could see. After a while we got tired and sat down on a plank that ran across a couple of oil barrels under a window of the engine-room and made ourselves comfortable. The window was open, and I could hear voices inside, but I supposed it was the engineer talking to some of his help and didn’t think anything about it until whoever it was came closer. It was the engineer, all right, but I couldn’t make out from the sound who was with him, though there was something familiar about the voice.

“They’re goin’ to turn steam into the thing at nine o’clock,” said the engineer. “Funny-lookin’ contraption, ain’t it?”

“Um!” said the other man. “Why didn’t you telegraph me sooner?”