Thus armed, Duncan set to work in earnest.
"Why isn't your output of coal larger than it is?" he asked of Davidson, the superintendent.
"I can't make it larger under the circumstances."
"What are the circumstances? What difficulties are there in the way? You have miners enough, surely."
"Well, for one thing, the mine is badly ventilated. Many of the best galleries are filled with choke-damp, and must be kept closed."
"Why don't you improve the ventilation? As an engineer you ought to know how to do that much."
"It isn't feasible, as you would know, Mr. Duncan, if you knew anything about mining."
"Oh, never mind my ignorance. It is your knowledge that I'm concerned about just now. Do I understand you to say that a mine lying only seventy-five feet or so below the surface cannot be ventilated?"
"I suppose it might be if the business could afford the expense."
"The business can and will afford any expense that may be necessary to make it pay. If you know enough of engineering to devise a practicable plan for ventilating the mine, I'll furnish you all the money you need to carry it out."