enemy was there. And should Dirk not come back it was still very unsafe, for he might be guarding the other entrance. But the matter was soon to be solved in a way very different from any he could possibly have imagined.
While he stood considering his course, he was startled by a curious rumbling sound that appeared to emanate from the very earth under his feet. Then there were grinding and groaning noises, low and indistinct, but terrifying beyond imagination. Gysbert’s hair fairly rose on his head, and something impelled him to beat the hastiest kind of a retreat. Turning on his heel, he ran with all speed to his boat, unmoored it, pushed it off, and rowed far out upon the black water.
Suddenly there was a terrific sound like an explosion, then a crash that shook the earth for miles around, and made Gysbert’s little boat rock on the waves till it all but overturned completely. When the boy recovered
