“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.