"No; didn't I tell you I flew again? I'm getting to be an expert. First I flew over in the open-hearth building and landed on a girder. This time I tried a more ambitious flight, landing on a hot stove. All the stuff from the eruption fell down on me and woke me up after a little. I nearly fell off trying to reach the guy-wire that I knew was there. You know the rest. I took a slide down the wire that would have made a Japanese performer turn pale. Then you and I had a collision."

"Well," laughed Steve, "it's all over now, you can get back to work."

"What? Up there again?"

"Of course."

"No, siree! Not for Robert Jarvis. He knows when he has had enough. He can get into enough trouble right down here on the ground floor. He doesn't have to perch on the edge of a crater looking for trouble. Did anything happen down here?"

"What did happen?" questioned Steve, turning to the head melter.

"Flare-back and——"

"What caused it?"

"I don't rightly know—"