As he gained the side of the chimney and stood there in the rain, slush, and wind, he saw a sight that both thrilled and chilled him. The mysterious student in white was crawling up the gable and was already close to the ridge!
"Shadow Hamilton!" murmured Dave. "He is sleep-walking again!"
Dave was right—it was indeed poor Shadow, and as fast asleep as a sleep-walker can get. The lad had a tape measure in one hand and was muttering to himself:
"If the gable of a house is fourteen feet long on one side, and the angle at the top——" And then the rest was lost in the wind.
"He's dreaming of that problem in geometry," said Dave to himself. "It's got on his nerves."
He wondered what he could do to aid the sleep-walker. He was afraid to call to Shadow, for fear the boy might awaken suddenly and tumble off the roof. Shadow was now on the ridge, and, to Dave's added horror, he stood upright, the tape measure in his hands. Then he began to walk to the very end of the ridgepole.
"If he falls into the yard he'll break his neck sure!"
Such was Dave's agonizing thought, and despite the cold, the heavy perspiration stood out on his forehead.
"Dave!"