"Not without help. But we can easily give it help."
"How? Go on. Explain your plan fully."
"Well, we have here three or four of those big fans that the government had made for the purpose of ventilating the engine rooms and stoke holes of its ironclads. They utterly failed and were sold as junk. Captain Hallam bought a lot of them at the price of scrap iron, and sent them out here. Davidson tried one of them and reported utter failure as a result. The failure was natural enough, both in the case of the ironclads and in that of the mine."
"How so?"
"Why, in both cases an attempt was made to force air down into spaces already filled with an atmosphere denser than that above. That was absurdly impossible, as any engineer not an idiot should have known."
"And yet you think you can use these fans successfully in ventilating the mine?"
"I do not think—I know. If Mr. Davidson will permit me to explain——"
"Never mind Davidson. If this experiment is to be tried you shall yourself be the man to try it. Go on, please."
"But, Duncan, I simply mustn't be known in the matter at all."
"Why not?"