“Wouldn’t it be though—”
“But say!” Johnny exclaimed. “Why not use it for mining coal?”
“It has been done in Europe.”
“Look!” Johnny stood up. His eyes gleamed. “Bex says that old Uncle Mose’s mine contains the toughest vein of coal he ever saw. He picks away at it for hours and only gets a small load. Suppose you could spare a little of that liquid air?”
“Yes. Sure.”
“I’ve got some charcoal,” Johnny was growing enthusiastic. “Whole lot of it. I got it from a charcoal burner. Got some fuse too.” He was fairly dancing about. “We’ll make up some of that carbon-liquid air explosive and loosen up ten tons of coal for old Uncle Mose. What a lift that will give him!”
“All right,” Donald agreed. “I’ve always wanted to try that thing out. We’ll do it this very afternoon. What do you say? Around four o’clock?”
“Suits me fine.” Johnny grabbed his hat. “Got a thing or two that must be done. I’ll be back later for my next lecture on liquid air. It sure is great!” He was away.
CHAPTER XIII
A STRANGE BEAR HUNT
Four-thirty that afternoon found the two boys trudging along the mountain trail which Johnny, Bexter, and Ballard had followed on that sad but eventful day when the swinging bridge went down.