Mr. Cooper waved his hand to silence Jimmy, and went on swiftly: “What Mr. Hope told you about it we don’t know. Evidently he didn’t describe it very accurately, but perhaps that was because he thought it unimportant, anyway. But Mr. Hope isn’t here now to explain his actions if you think they need explanation. And, chief, I happen to know that he’s coming in to consult you this afternoon on this very matter. That’s a fact, chief, he is. You wait and hear what he has to say, then you’ll understand it all. And Rand and I will both be here; just send for us if you want us.” The president stared searchingly at his two employees an instant. Then abruptly he resumed his former manner of attentive listening. “Go on with your scheme, Mr. Rand; you interest me.” Jimmy suppressed with an effort the anger that this new proof of Mr. Hope’s duplicity had aroused in him, and resumed: “You understand, Mr. Wentworth,” he interrupted himself when he had been talking perhaps five minutes, “I’m not going to try and talk to you in technical language. I’ve only studied these engineering problems a little with George. I think I can make the thing clear in a general way, but I can’t talk technically.” “I couldn’t understand you very well if you did,” the president observed. “That’s always been up to my technical men.” “As I said, sir,” Jimmy went on, “the—” “The first problem is how you propose to burn the coal,” Mr. Wentworth interrupted. “Tell me about that first.” Jimmy explained how they would bore down to the coal measures, just as borings are made in prospecting. “This would be a small vertical shaft,” he added. “How big in diameter?” “About twelve or fourteen inches. Then this shaft would be lined with iron casing—” “Like an oil-well,” Mr. Cooper interjected. The president nodded. “At the top of this shaft we put a fan—just like the fan-house of a coal mine, only very much smaller—to blow the air down. This is the air-shaft; parallel with that we bore another just like it.” “How far away?” asked Mr. Wentworth. “The distance wouldn’t make much difference—say fifty feet,” Mr. Cooper put in. Again the president nodded. Jimmy continued. “Then we blast a connection between the bottoms of the two shafts through the coal.” This the president discussed at some length. “Why not put the shafts closer together?” he finally asked. “No reason that we can see,” said Jimmy. “If they were closer it would make the connection down below easier. This second shaft is the one that brings up the gaseous products of combustion. “We’re going to use your regular regenerative furnace, or one something like it. We can get you producer gas that is just as good as any you’re getting—from the coal we burn in the ground, if we control the air and steam right.”