"How did it happen?" he asked.
"I was crawling along through the tunnel when I saw this pile of boulders ahead. At first I was going to turn back, but I thought that when I had come this far it was foolish to turn around, so I started to climb over the boulders. Just as I was almost over, that big boulder slid down against the other one—and there I was. Lucky I didn't break my leg."
"I'm afraid to move that boulder the wrong way, or it might roll over onto you. There's only one way to move it safely and that is to lift it straight up, just enough to release your foot. But I'm afraid I'm not strong enough."
"Try it again, anyway."
Again Joe applied himself to the heavy rock. Although he strained and gasped in his efforts to move it, the boulder defied his efforts and he was unable to budge it an inch. He made attempt after attempt, but it soon became evident that the effort was beyond his strength, and at last he was forced to sink back, exhausted, against the wall. He mopped his brow.
"Too heavy!" he declared, out of breath.
Frank was silent.
"If we only had a crowbar of some kind!" he suggested at last. "It wouldn't be hard to move it then."
Joe looked up.
"Why, I saw a crowbar back in the mine!" he exclaimed. "It will be the very thing."