Again and again he had worked his brains to weariness, trying and trying to invent some machine that should wake him.

But although he was older and cleverer now, he fared no better than when he wanted to wake himself to help his mother with Agnes.

He must have some motive power before he could do anything, and the clock was still the only power he could think of, and that he was afraid to meddle with, for its works were beyond him, and it was so essential to the well-being of the house that he would not venture putting it in jeopardy.
One day, however, when he was thinking nothing about it, all at once it struck him that he had another motive power at his command, and the thought had hardly entered his mind, before he saw also how it was possible to turn it to account.

His motive power was the stream from the Prior's Well, and the means of using it for his purpose stood on a shelf in the ruins, in the shape of the toy water-wheel which he had laid aside as distressingly useless.

He set about the thing at once.
First of all, he made a second bit of channel for the stream, like a little loop to the first, so that he could, when he pleased, turn a part of the water into it, and let it again join the principal channel a little lower down.