scuttle had been thrown open, and wind and rain were coming down through the opening.
Dave's curiosity was now excited to the top pitch. He felt sure that the servants had not left the scuttle open on retiring or that it had been blown open by the wind. Consequently, the midnight prowler must have opened it, and if so, for what purpose excepting to get out on the wet and slippery roof?
Suddenly an idea flashed into Dave's mind, and without further ado he ran to the ladder and mounted it with all speed. At the top he thrust his head through the scuttle opening and looked around that portion of the school roof which was visible from that point.
He had expected to see a certain person, but he was disappointed. Yet this did not make him hesitate regarding his course of action. He crawled out on the roof, slippery and treacherous with slush, and made his way cautiously but rapidly to where there were an angle and a high gable, with a wide chimney between.
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!"
