The entrance hall was delightfully enclosing and reassuring, full as always of flowers and birds' nests, the lights relayed from mirror to mirror all down its length, and all the scatter of happy living - secateurs, baskets, books, letters and anything-to-hand lying on the tables. The coloured stairs led up invitingly, but to get to the attic you had to pass through the Knights' Hall, which, if it had been alone for some hours, had a habit of slipping back to its own century. However much you loved it, Tolly thought, it always needed a little resolution to break away into its privacy at night.
'You didn't tell us anything about the witchball,' he reminded Mrs Oldknow, to postpone the moment. 'May we see it, please?'
The witchball was hanging from the middle beam of the room nearest the front door. It was made of looking-glass and had a diameter of about eighteen inches. The glass was old and the silvering was old. It did not glitter like modern glass, but reflected in an almost velvety way. Being round, what it reflected was a spherical room, something difficult to look at because impossible to imagine. There were no straight lines at all, no right angles. Floor, ceiling, doors, windows, tables and chairs all curved softly around its shape. Ping and Tolly, standing underneath looking up at it, appeared to be diving out of it face first, their bodies foreshortened and tapering, like tadpoles.
'You see,' said Mrs Oldknow, 'it reflects everything, even what is behind it, though that for some reason is upside down, which is supposed to be how our eyes really see things.'
'What is it used for, Granny?'
'Is it for seeing the future?'
'It looks as though it should be. You could easily see strange things in a spherical mirror-room where even ordinary things look so queer. Something could be there for quite a long time before you noticed it. Besides, it's always easier to see visions in a glass than in reality. But I believe it was supposed to keep away demons. I don't know why. Perhaps because if anyone had an attendant demon and came anywhere near the witchball they would risk the demon being seen. You must admit it looks magic enough for anything.'
'You would have to learn how to look into it,' said Tolly sensibly. 'It is difficult to recognize things in it, especially upside down.'
'A demon, if there was one,' said Ping, 'wouldn't like being reflected, even if no one saw. It might steal some of his power.'
'I'm sure that's right, Ping,' said the old lady. 'Unlike ghosts who want to be seen and use looking-glasses to do it.'
'I suppose that is why you have so many looking-glasses in the hall,' said Tolly. 'I like the house-ghosts too. But I think I would be happier tonight if the witchball was hanging in our bedroom. May we take it up? I don't want any of Dr Vogel's companions clutching at me.'
Mrs Oldknow laughed. 'Don't tell me you have sold your soul so young! I am counting on you to be one of the stalwart guardians of the place. You should be clutching demons by the tail, not they you.'
'Green Knowe doesn't need guardians,' said Tolly, showing in his face how proud he was of it. 'It can't have any enemies.'
'It has enemies and it needs guarding all the time,' said the old lady. 'In spite of all the Preservation Societies it wouldn't be there another five years if we stopped watching and guarding it. The very fact that it has lasted so long makes some people impatient. Time it went, they say, without further argument. The fact that it is different from anywhere else, with memories and standards of its own, makes quite a lot of people very angry indeed. Things have no right to be different. Everything should be alike. Over and above all the rest, it seems to me to have something I can't put a name to, which always has had enemies. Lift the witchball down, Tolly. We'll take it up to the attic. It is wasted in my workroom. It really is a beauty.'
They carried it carefully upstairs and hung it from a beam. It was a great addition. It reflected back Ping and Tolly in their beds, though even when they sat up and waved their arms it was difficult to find themselves in it. One is not used to seeing one's self feet upwards.