One day he descended to the lower level, where the men were having trouble in the manager's absence. A number of lamps were burning and the place looked wetter than usual in the unsteady light. Water trickled down the end wall, the rows of props were dripping, and the half-naked men splashed through pools when they moved to and fro. They were feverishly busy: one group building a massive pillar, others putting up fresh props; only two or three were breaking out ore at the working face. Then Carnally came toward him, and his wet face showed tense and anxious in the light of Andrew's lamp. "The blamed roof's very shaky," he said. "We've had two ugly cave-ins. I wish Watson was back. And I'm getting scared about the water; expect we're tapping a tank-pot in the hill, but there's nothing to help us in locating it. You might give the boys a hand with the pillar." Andrew stripped to shirt and overall trousers, and hurried toward the spot. He saw that the men needed help, for the cracked roof was bulging downward ominously and there were several heaps of freshly fallen stones. They were constructing a square frame of logs, crossed at the ends, and filling it in with broken rock as fast as they could; but there remained a wide gap between its top and the roof it was meant to support. For an hour he worked savagely, wet with falling water and dripping with perspiration, passing up heavy beams and stones to the men who laid them in place. He grew breathless and tore his hand, but the flakes of rock which fell at intervals urged him on. Once or twice there was a crash farther down the tunnel and he saw shadowy figures scatter and others run in with props, but for the most part he fixed his attention on his task, because it looked as if they had no time to lose. When a gush of water flowing down the heading splashed about his boots, he called Carnally. "Is this tunnel going to cave in?" he asked. "That's more than I can tell," Carnally replied. "We may be able to shore her up, but if it's not done soon, the chances of her crushing in are steep." "I see," said Andrew, and turned to his companions. "Boys, I'll stand for a ten-dollar bonus if this job's finished in half an hour." One of them laughed, but there was no other response and they did not seem to increase their exertions much. This suggested that they had been doing their utmost already, with a clear recognition of the risk they ran. Their pay was good, but something besides their interest urged them to keep the mine open. These were men who would not easily be beaten by inpouring water or crushing rock: they had braced themselves for a grapple with their treacherous natural foes.