"Never mind that now—you'll know some day—when my father gets possession of the island," answered Slugger rather importantly.
The best part of half a mile more was covered, and then Barney Stevenson left the trail and plunged in among a wilderness of trees and rocks. He had to take off his snowshoes, and he hung them up in a tree. Then he went ahead once more, presently reaching the foot of a little cliff. Here there was an opening six or seven feet in diameter, and he disappeared into this.
"What do you know about that?" cried Nappy in a low voice. "Is that a cave?"
"That's just what it is!" answered Slugger triumphantly. "I only hope it's the cave my father wanted to locate."
"Why does he want to locate a cave on this island?" asked Nappy, more curious than ever.
"You'll know some day, Nap. Now come on—let's try to find out what the old man is going to do in that cave."
With caution, the bully and his crony made their way over the snow, and then slipped inside the entrance to the cave. Ahead of them they saw the flicker of a lantern which Uncle Barney had lit.
The cave was irregular in shape, running back a distance of a hundred feet or more. As the old man advanced he held his gun ready for use, thinking that possibly some wild animal had taken possession; but no animal of any sort appeared.
Coming to the back end of the cave, the old man set down the lantern on a rock. Then he got down on his knees and began to pull away at a large flat stone, close by. He worked rather feverishly, as if growing more nervous every instance.
"It must be here! They couldn't have gotten it away from me!" he muttered to himself.