And now, past the curving point of the land, Joe set his thoughts on the far end of the lake and put every bit of effort into his swaying body. Just when the plan to follow Rat Brook on skates instead of seeking road or trail came to him he could not have told. It was there, suddenly, in his mind the moment he reached the turn of the shore. He no longer sought concealment nor smooth ice, but headed as straight as his sense of direction pointed. The farther shore leaped out at him from the darkness suddenly and he had to check his speed to duck under the little bridge. Then he was off again, the ice-roofed brook stretching ahead of him plainly discernible in the faint early radiance of the stars. His skates seemed to awake hollow echoes, but the ice was firm beneath its occasional crust or light blanket of snow. Rat Brook had little current, so little that it froze almost as soon as the lake, and while the water moved sluggishly beneath the ice it did not weaken it. There was a straight stretch, like a canal, for nearly a quarter of a mile, and then the brook turned to the right, following the base of Little Rat Mountain, and after that curved continuously. Often the forest closed in on both sides and Joe must perforce trust to luck rather than to vision, yet save once or twice he held his course. Branches slashed at him, and now and then a protruding root or fallen tree strove to trip him. But somehow, in some instinctive fashion, he passed them all safely and without decreasing his speed. Had he stopped thinking of his errand long enough to consider that speed he would have been tremendously surprised, for he was skating just about twice as fast as he had ever skated in his life, and, moreover――which, if Hal was right, was possibly the reason for it――doing it without conscious thought! The brook had been turning slowly to the right for some minutes when, reaching a clear stretch, Joe saw trouble ahead. The brook broadened where a second stream entered and a blacker path there told him that he was looking at open water. He might stop, with difficulty, and veer into the inhospitable arms of the trees and shrubs, or he might keep on, trusting to luck to find ice along the margin. He chose the latter. Then there was a gurgling and murmuring of water in his ears, a wide pool of moving water at his feet and the swift realization that for at least three yards the ice was gone from bank to bank!