Skipper Ed, satisfied that Bobby and Jimmy were close at his heels, did not halt again until well out over the smooth ice and near to Itigailit Island, when he heard behind him a strange rumbling and crackling. He halted and listened, and strained his eyes through the drifting snow for a glimpse of the boys. They were not visible, and, springing from his _komatik_, he ran back in the direction from which he had come and as fast as he could run, and presently, with a sickening sensation at his heart, was brought to a halt by a broad black space of open water.