Moving pictures

'Yelling what?'

'Dunno. P'raps 'Give me a towel!' '

'Bet he'd be yellin' all right if he tried that sort of thing round here,' said Throat cheerfully. 'Now, ladies and gents, I have here some sausage in a bun that'd make your-'

'Eureka,' said the soot-coloured one, swaying back and forth.

'What about it?' said Throat.

'No, that's the word. Eureka.' A worried grin spread across the black features. 'It means 'I have it'.'

'Have what?' said Throat.

'It. At least, I had it. Octo-cellulose. Amazing stuff. Had it in my hand. But I held it too close to the fire,' said the figure, in the perplexed tones of the nearly concussed. 'V'ry important fact. Mus' make a note of it. Don't let it get hot. V'ry important. Mus' write down v'ry important fact.'

He tottered back into the smoking ruins.

Dibbler watched him go.

'Wonder what that was all about?' he said. Then he shrugged and raised his voice to a shout. 'Meat pies! Hot sausages! Inna bun! So fresh the pig h'an't noticed they're gone!'

The glittering, swirling idea from the hill had watched all this. The alchemist didn't even know it was there. All he knew was that he was being unusually inventive today.

Now it had spotted the pie merchant's mind.

It knew that kind of mind. It loved minds like that. A mind that could sell nightmare pies could sell dreams.

It leaped.

On a hill far away the breeze stirred the cold, grey ash.

Further down the hill, in a crack in a hollow between two rocks where a dwarf juniper bush struggled for a Ping, a little trickle of sand began to move.

Boom.

A fine film of plaster dust drifted down on to the desk of Mustrum Ridcully, the new Archchancellor of Unseen University; just as he was trying to tie a particularly difficult fly.

He glanced out of the stained-glass window. A smoke cloud was rising over uptown Morpork.

'Bursaar!'

The Bursar arrived within a few seconds, out of breath. Loud noises always upset him.

'It's the alchemists, Master,' he panted.

'That's the third time this week. Blasted firework merchants,' muttered the Archchancellor.

'I'm afraid so, Master,' said the Bursar.

'What do they think they're doing?'

'I really couldn't say, Master,' said the Bursar, getting his breath back. 'Alchemy has never interested me. It's altogether too ... too ... '

'Dangerous,' said the Archchancellor firmly. 'Lot of damn mixin' things up and saying, hey,