"How much powder have you, Bill?" Jack asked.
"Four twenty-pound cans."
"Let us let off ten pounds at a time," Jack said. "Just damp it enough to prevent it from flashing off too suddenly; break up fine some of this damp wood and mix with it, it will add to the smoke."
In a few minutes the "devil" was ready, and a light applied; it blazed furiously for half a minute, sending volumes of light smoke up the shaft.
"Flash off a couple of pounds of dry powder," Bill Haden said; "there is very little draught up the shaft, and it will drive the air up."
For twenty minutes they continued letting off "devils" and flashing powder. Then they determined to stop, and allow the shaft to clear altogether of the smoke.
Presently a small stone fell among them—another—and another, and they knew that some one had noticed the smoke.
