Come with me, cousin Dorothy.' He led the way from the room, and began to ascend the stair which rose just outside it.

Dorothy followed, winding up through the thickness of the wall.

And now she could not hear the engine.

As she went up, however, certain sounds of it came again, and grew louder till they seemed close to her ears, then gradually died away and once more ceased.
But ever, as they ascended, the rushing sound which had seemed connected with it, although so distant, drew nearer and nearer, until, having surmounted three of the five lofty stories of the building, they could scarcely hear each other speak for the roar of water, falling in intermittent jets.

At last they came out on the top of the wall, with nothing between them and the moat below but the battlemented parapet, and behold! the mighty tower was roofed with water: a little tarn filled all the space within the surrounding walk.