“We’re too tired to chew off any more excitement to-night,” was the way he put it; so they led the jacks back to one of the larger chambers where the peek-a-boo torrent, as Dick called it, took what appeared to be its final dive underground, moved their packs, and, unrolling the blankets, turned in on the hard floor to sleep as they could.

It was half-past five in the morning when Larry’s self-tripping mental alarm clock went off, and he got up and roused his two companions.

“Time’s up,” he said. “Help me get the mules and the stuff a little farther back out of the way and we’ll shoot the moon.”

They made their preparations for the big shot with some little trepidation. Dick, who, because his father was a mine owner as well as a railroad manager, knew the most about underground mining, was the mainstay of the other two.

“We needn’t be nervous,” he said. “Half the time the miners don’t take the trouble to go back very far in a tunnel, even when they fire a whole round of blasts. What you do is to hold your mouth open and cover your ears with your hands. And with all these crookings there’s no fear of flying rocks.”

When everything was as ready as they knew how to make it, Larry took the lighted candle and went to put fire to the fuse, which they had cut long enough to give the firer plenty of time to rejoin his companions. When he came back, the hand that held the candle was shaking a little, in spite of all he could do. “She’s going,” he announced, and then they blew the candles out and cowered against the nearest rock wall in the black darkness to wait for the shock.

To all three it seemed as if the waiting interval would never end. Time, at such a crisis, moves as if it were leaden-winged. Dick had his mouth open, but he held his breath until he was about ready to burst. “Gracious!” he gasped, “did we cut that fuse a mile long?”

If either Larry or Purdick made any reply there were no ears to hear it. The fire had reached the dynamite at last. There was a sucking blast of air that seemed to be trying to tear them loose and fling them back into the rearward depths, a noise that was like a collision of worlds, and then a sickening gust of the powder fumes to warn them not to be in too much of a hurry to run forward to see what the big blast had accomplished.

They didn’t hurry. After a wait of about five minutes, Larry relighted his candle, and they waited again until the candle flame was burning brightly to show that the deadly fumes were dissipating. Then they crept forward cautiously. Around the last of the crooking turns in the passage they found a litter of broken rock, and they were almost afraid to look into the boulder nest. What if the shock had brought down the roof, and so trapped them more securely than ever?

It was Dick who got the first look. “Hooray!” he yelled. “We did it! She’s wide open—you could drive a wagon through!”