I heard them open it.

Now, both together now." The lads fell over their feet, and were in another minute at the window.

The broad top of the great wheel stretched out level with them, hiding the window from those who might have been standing below.

The wheel itself was some thirty feet in diameter, and was sunk nearly half its depth in the ground, the water running off by a deep tail race.
"We might lie flat on the top of the wheel," Hugh said.
"We should be roasted to death when the mill is fairly in flames.
No, Hugh; we must squeeze through this space between the wall and the wheel, slip down by the framework, and keep inside the wheel.
There is no fear of that burning, and we shall get plenty of fresh air down below the level of the mill.
"I will go first, Hugh.

Mind how you go, for these beams are all slimy; get your arm well round, and slip down as far as the axle." It was not an easy thing to do, and Rupert lost his hold and slipped down the last ten feet, hurting himself a good deal in his fall.