But first she walked round the main floor, liking the way the machinery seemed to watch her, liking the feeling of its latent energy. Into her mind slid a new thought, like a questing serpent, How easy would it be to open the sluice gates, and to force Twygrist into life again?
An immense stillness seemed to fall over everything, as if the dark core of the old mill had heard and was listening. It’s alive, thought Donna. It’s been decaying and idle for years–decades–but there’s still something here that’s living. And that something has heard my thoughts, and it’s waiting to see what I’ll do.
How did the sluice gates work? Donna had a distant memory of her father saying something about a pivot wheel that would have to be turned with a splined key. The same principle you used when you opened a tin of sardines or corned beef, he said, and Donna’s mother had instantly said that if he was going to use analogies, please would he use ones they could understand, because she had never opened a tin of corned beef in her life. Donna’s father had laughed, and said, all right, then, a horizontal wheel, with a grooved shaft at the centre; you slotted the key down into that shaft, and then turned the key.
Donna saw the wheel almost at once. It had black spokes and jutted up about a foot from the floor. It was quite near the door leading underground. What looked like the spline key was lying nearby.
She walked slowly forwards, her eyes fixed on it. It would not work, of course: the mechanism would long since have seized up. And even if, by some slight chance, it did work, the culvert would have rotted away years ago. She glanced overhead. Yes, there was the culvert, just as she remembered from that last summer here. The clay had broken away from most of it, but it might be still be watertight.
She picked up the spline. It felt cold against her fingers and the surface was pitted with age. Presumably you slotted it down into the wheel’s centre, as her father had said, and then turned it using the t-shaped handle. The splines would force the wheel’s mechanism to rotate. It really did look as if it worked on the corned-beef-tin principle.
The wheel was about two feet across. Donna leaned down and tried the key in the centre. It slid home obediently, and she grasped the t-handle. Just a tiny pressure, just to see if the wheel was still capable of rotating. She turned it slightly to the right, encountered resistance, and then tried it the other way. This time the whole shaft of the key seemed to engage, and the wheel moved to the left. Only a little–barely the distance of one of the spokes–but Donna instantly felt an answering tremor. Like thunder growling far away. And had the oak floor shivered briefly at the same time, or had that been her imagination?
Her hand was still on the key. She was not going to take this much further, but if she could just know how workable the mechanism was…
The wheel turned a little further, and this time there was no doubt about it; an unmistakeable tremor went through the floor, like the accounts you read of the start of an earthquake. At the same time a breath of something stagnant and cold seemed to brush against Donna’s skin.
If the sluice gates were raised, hundreds of tons of water would tumble down into Twygrist from the reservoir, and the waterwheels would begin to turn.
The light shifted suddenly, and there was a new sound behind her–a sound that had nothing to do with the struggling old mechanism. Donna spun round, and in the centre of the floor, watching her with puzzled eyes, was a woman of thirty or so, with shoulder-length fair hair.
After a moment the woman said, ‘I didn’t realize anyone was here.’ But her eyes were on Donna’s hands, still grasping the sluice wheel. ‘That’s awfully old machinery,’ she said after a moment. ‘It’s probably a bit dangerous to be too close to it.’