They traveled carefully at first, for there were sinks in the ice which had barely skimmed over since sun-down. The thermometer registered 18 above zero, however, and the biting cold was congealing all lakes and pools very rapidly. Where they tramped through the slush their footprints froze behind them. In an hour the mercury had fallen ten degrees more and they were beating their gloved hands across their breasts to keep up the circulation. They tramped on at good speed for several hours. Here and there along either edge of the glacier, were groves of fir trees like the one they had encamped in. But in places the ice had melted from under and around these patches of rock and soil and the roots of the trees were exposed, while the earth had slumped away in small land-slips until nothing but a heap of debris was left. The old professor grew weary and Andy insisted upon making camp again and resting. While they were warming themselves over the fire the old hunter built, and Wash was boiling some coffee, Jack suddenly beheld several shining points of light in the little wood on the edge of which they had halted. "Look out! We're being watched," he whispered in Andy's ear. The hunter grabbed his rifle and looked where Jack pointed. At once he seemed relieved. "The wolves," he said. "They know their way out of this valley. I don't want to travel on this ice any longer than I can help." With a word to the professor, and taking Roebach with him, the old hunter made a determined charge into the brush at the lurking wolves. The pack scattered at first, but finding themselves determinedly followed, and both hunters having been wise enough to take torches with them (for wolves are very much afraid of fire) the pack finally gathered once more and trailed away up a narrow path upon the rocky wall close at hand. In the white light furnished by the earth-planet Andy counted thirty and more of the beasts climbing this rugged path. He was sure it was no mere lair they went to among the rocks, but a path leading out of the valley altogether. Therefore, when the party was again refreshed, they took up their line of march, in single file, following the wolf trail. CHAPTER XXIII THE FIGHT AT ALEUKAN Phineas Roebach knew nothing about this narrow defile through which the party traveled. But he agreed that they were breaking through the wall of the glacier on the right side. Aleukan, the big native settlement, was in this direction. There seemed to be a narrow crack through this cliff which had guarded the river of ice. It had never been used by man as a right of way, but the beasts of the wilderness had used it from time immemorial, as the marks along the way proclaimed. The scurrying feet of the wolf pack, were long since out of the way. But yonder a mountain sheep had been killed by a puma, or other big feline, and the wolves had picked its bones after the Master of the Chase had eaten his fill.