He stood for some time, debating whether he should remain where he was until the coming of day, in the hope of gaining additional light, or whether he should venture upon a little cautious exploration. He finally decided upon the latter. “When the elephant goes on a bridge, he feels of it with his trunk to see whether it is strong enough to bear him, and I'll use my gun to do the same thing.” This was no more than a simple precaution, and doubtless saved his life. Grasping the stock firmly, he reached the muzzle forward, and “punched” the ground pretty thoroughly before venturing upon it, making sure that it was capable of bearing him safely forward into the darkness beyond. Generally speaking, the ground of the cavern was tolerably even. There were little irregularities here and there, but none of them were of a nature to interfere with walking, provided one could have enough light to see where he was going. “If I only had a lantern, I could get round this neighborhood a good deal faster than this,” he said. “It wouldn't be anything more than fun to explore this cave, which may be as big as the mammoth one of Kentucky.” Up to this time Fred had been moving almost directly away from the cascade which he had noticed. The misty light over his head served somewhat as a guide, and he determined not to wander away from that, which would prevent his getting lost in the bowels of the earth. The boy was quite confident that there was some easy way of getting out of the cave; for if there was none, except by the opening above, then he was in a Bastile, most surely. It was undoubtedly the cascade which added to this conviction, for it seemed to him more than likely that if the water entered and left the cave, the volume which did so must be of a varying quantity, so that at certain seasons it was capable of carrying a boy with it. This, of course, was extremely problematical, but it was hopeful enough to prevent anything like despair taking possession of the lad as he felt his way around the cavern. “Every stream finds its way to the daylight after a time, and so must this, and why can't it take a fellow along with it? That's what I should like to know---” He paused, with a gasp of amazement, for at that moment the gun went out of his hand as suddenly as if some one in waiting had grasped the muzzle and jerked it away. But there was no human agency in the matter. While punching the surface, he had approached a vast abyss, and the thrust over the edge was so unexpected that the impulse carried it out of his hand. As the boy stood amazed and frightened, he heard the weapon going downward, Heaven could only tell where. First it struck one side, and then another, the sound growing fainter and fainter, until at last the strained and listening ear failed to hear it at all. The depth of the opening was therefore enormous, and Fred shuddered to think how nearly he had approached, and by what a hair's breadth he had escaped a terrible death.