"'I'm going to find Jim!' he insisted.
"'If you must run chances, why, I suppose you must,' said I. 'But I'm going to stay here, where the air's good. Try to get back here. Keep in touch. You take ten paces forward, then stop and shout. I'll answer. If you don't hear me, come back.'
"He promised and started off. For the first fifty yards or so—supposing that he shouted at every ten paces—I heard him clear enough.
"Then—not another sound! What had happened to him?
"I shouted again and again.
"No reply!
"What was I going to do? Both Jim and Anton were wandering around loose in the mine galleries, and they might stray until they dropped, without ever finding the way back. I yelled till I was hoarse.
"Then I got another idea. I took my pick, and kept on hitting the roof in three regular strokes: 'Tap! Tap! Tap!' and then a pause—just like that." He illustrated on the head-rail of his hospital bed. "I knew that the vibration would carry along the rock, farther than the voice."
"That's what the geophone man heard," Owens commented to the reporter. "Go on, lad!"
"I kept that up," Clem went on, "until my arms ached. I was so tired in my back and so weak with hunger that bright violet spots kept dancing before my eyes. But I kept on, just the same.