A dull report sounded in the furnace itself.
"Look out for the flareback!" roared Pig-Iron Peel. "Run for it!"
Now a new sound smote their ears. It was a rumbling noise that seemed to start away down in the foundations of the blast furnace, working upward at a rapid rate.
Steve, who had quickly leaped from his dangerous position, glanced at the head melter inquiringly, as if to ask what this new thing might be.
"It's a hang-over!" shouted the melter. "Now we are in for it!"
CHAPTER XVIII
IN A FIERY RAIN
STEVE RUSH did not know what a hang-over might be. He had just had a practical demonstration of what a flareback was. This, however, he did not know was caused by an explosion of the molten metal, either from a stream of water touching it or a too sudden inrush of cool air. At any rate the metal in the furnace, just as the dolly was driven in, had suffered a partial explosion. The air was full of molten metal shooting in all directions. Some of the men back of where the monkey-man had been standing had been quite seriously burned in the explosion.