'Well, I haven't,' said Colin. 'This is as far as I can go.' He sat on one of the ledges, away from the drop.

Meg went to the tip of the point and looked down and about her. 'Wow.' She spread her arms. 'Wow! Whee!'

'Please,' said Colin.

'What a view,' said Meg. 'And the wind's great. I could fly.'

'Don't,' said Colin.

'Geronimo!'

'Please come back, Meg.'

She began to whistle a tune.

'What's that?' he said.

'Something we used to sing in the playground at school.'

'I've heard it before.'

'I shouldn't wonder. You were a kid once. We all were.'

'Please come away from there,' said Colin. 'You're making my insteps hurt.'

Meg turned round, her back to the drop. 'It can't harm you,' she said. 'The rock has no opinion.'

'Hasn't it? Please.'

'You great mardy. You're frit.' But she came and sat by him and looked to the hills. She hummed the tune.

'What is that?' said Colin.

'You know,' she said, and began to sing quietly and slowly.

'The wind, the wind, the wind blows high.

The rain comes pattering down the sky.

She is handsome, she is pretty, She is the girl of the windy city.

She has lovers, one, two, three; Pray will you tell me who is she?'

'I know it. Somewhere,' said Colin. 'Yes. Bert whistled it. But I have heard it before, too.'

'I tell you what,' said Meg. 'I'm ready for that lamb.'

'Of course,' said Colin.

'Come on then. Let's go. Doesn't the telescope look good from here?' Away to the south the structure stood out from the land as a bowl, pointing straight up. 'What's it doing?'

'Nothing at the moment,' said Colin. 'It's in the zenith; what we call "parked".'

'At this distance it's a goblet, or even a chalice. It could be the Grail.'

'It's certainly a Questing tool,' said Colin.

They left Castle Rock by a shorter way and came to Church Quarry from the side and down a path to the hut. Colin hung up his gown and opened the oven door.

'Mm. Smells delicious,' said Meg.

Colin tried the meat with a fork. 'Perfect.' He lifted it out and set it to stand.

The table was already laid.

'I like your silver,' said Meg.

'It needs to be used.'

'Couldn't agree more. If you've got it, flaunt it, that's my motto.'

Colin put an oil lamp on the table. He lifted off the globe of frosted gla.s.s, and removed the clear chimney. He set them side by side and took a pair of scissors and trimmed the two wicks, lit them, and turned them down until they burned a low flame. He left it for a while, then he fitted the chimney back on.

'What I can't stomach about period films,' he said, 'is that no one knows how to light a lamp. They're always flaring and smoking and the top of the chimney's black with soot. It kills all credibility. You have to start cool, wait for the gla.s.s to warm, and turn the wick up gently to give a clear flame. Like-' He checked that the wicks were level, and lowered the globe over the chimney. '-so.' He chose wood to put on the fire.

'You can't beat a log fire, can you?' said Meg. 'It's atavistic.'

'And it warms you three times,' said Colin. 'Once fetching, once splitting, once burning. But you have to know how to use that over there.'

'Hey. Some axe.'

'Scandinavian. They're the best. But you can't fool around with them. If you do, you're dead.'

'It must be four foot, if it's an inch.' Meg went to the corner where the axe stood and put her finger to the edge. 'Sharp as a razor. I see you keep it greased.'

'If you let it get dull the energy is dissipated through friction,' said Colin. 'And if rust takes hold you might as well thump wedges. Here's another lost art.' He took sheets of newspaper and rolled each tightly across from corner to corner to make a thin rod. He bent the rod into a triangle, leaving the two ends long so that he could turn them back and weave and lock them between the three sides. Then he crumpled a sheet loosely in the grate and laid the triangles on the paper. He built grids of kindling on top at right angles to each other. 'The secret is to make plenty of room for air.'

'Where did you learn all that palaver with rolling the paper?' said Meg.

'At the farm, I imagine.' Colin chose small logs, arranged them above and around the kindling, and lit the loose paper. 'The rule is, "One log can't burn. Two logs won't burn. Three logs make a fire." And mix them. Ash, thorn and oak are best, if it's heat you want. Birch, holly and fir for brightness.'

The rolled sheets were red, and blue flame spurted from their ends. The kindling caught.

'Brilliant,' said Meg. 'Strange how things often come in threes, isn't it?'

'Simple physics, in this case.'

'But who worked out the trinities? Ash, thorn, oak. Birch, holly, fir. Timber. Logs. Firelighters.'

'Empirical pragmatism,' said Colin. 'Nothing mystical or esoteric; though some would have it so. Now let's have a whiff of adventure, shall we?' He fitted a head torch on his brow and opened the door.

The hut sat in a corner of the quarry, and at the junction of the two sides was a tunnel into the rock. It had a gate of iron bars. He unlocked the gate and pushed it open.

'I want to show you something special. I think there'll be enough daylight. There it is. Look along the wall near the floor to the right. What can you see?'

'Rock,' said Meg.

'What's on the rock, just at the edge of darkness?'

'Oh, yes! It's beautiful! The rock's glowing. Green. Green jewels.'

'Go and touch them.'

Meg went into the tunnel.

'They've scarpered! There's nothing here!'

'Come back to the entrance and look again,' said Colin.

'Yes! I can see them! What is it?'

'Goblin gold,' said Colin. 'More correctly, Schistostega pennata. It's a moss; quite rare. It grows at the limit of photosynthesis, where there's no compet.i.tion. The effect's caused by the protonemata, which have adapted to capture the light in a narrow focus; a bit like cats' eyes on a road. So when you're at the right distance and angle they reflect. But when you go up close they appear to vanish; hence the popular name.'

'You're a rum little devil, our Colin,' said Meg.

'Party tricks. I don't really "know" very much, if anything, at all.'

'Well, you know more than me.'

'Don't we all tend to dismiss our own areas of expertise?'

Meg looked at him. 'Now that's insight. Though I still don't see why an astrophysicist needs to know about moss. You're daft, but you're not stupid.'

'The electro-magnetic spectrum is what's in common,' said Colin. 'Now let's get ourselves something to complement the meal.'

He stepped up into the tunnel and switched on his torch.

'What is this?' said Meg.

'Questions, always questions,' said Colin. 'It's a trial adit to test the quality of the rock. It runs along the horizon between the conglomerate and the dimension stone.'

'So the next question is: what's dimension stone?'

Colin laughed. 'Now that is a very good question. Which is it? Eighth? Ninth? Eleventh? Twelfth? Nth? Who can tell? But it's only the term the quarrymen used for the fine unlaminated sandstones that cut well in all directions. They drove the adit to see whether it was worth extending the quarry. It wasn't; so they stopped after twenty-seven metres. But it still has its worth. It makes an excellent cellar. Come along.'

'The way the pebbles catch the light,' said Meg. 'They're big, too.'

'Yes; and fine specimens. But we need to be further in, where it's darker.'

The entrance to the adit was round and wide, and became a narrower slot where Colin had to stoop.

'Here should be about right.' Colin took two small quartz pebbles from his pocket and switched off the torch. 'Watch this.' He held one in each hand and rubbed them hard together.

'Oh!'

There was a shimmer of cold moonlight from the pebbles.

'That's beautiful!' said Meg.

Colin rubbed them again. Again the light. He lifted a hand to the roof and rubbed one of the big pebbles in the rock. The light was brighter.

'How do you do it?'

'Triboluminescence,' said Colin. 'To oversimplify. Quartz, and bone for that matter, is a substance that contains piezo-electrical charge which changes polarisation when mechanical stress is applied, which manifests itself as light. We don't know for sure how this happens, but one theory is that the impact causes electrons to jump to a higher energy sh.e.l.l, then when they jump back to the original sh.e.l.l orbit their transition creates the light.'

'Yes, I did ask, didn't I?' said Meg. 'I did ask. I did. Wae's me. I did.'

'Quartz is the second most abundant mineral in the Earth's crust, and is made up of a framework of silicon-oxygen tetrahydra,' said Colin. 'And silicon lies directly below carbon in the periodic table, so that much of its basic chemistry is similar to carbon, which is the foundation of life here; which makes me wonder whether we're merely carbon chauvinists.'

'Breathe in,' said Meg.

'I'm not out of breath.'

'I am.'

'Theoretically,' said Colin, 'under the right conditions, you could have a silicon-based life source, and I personally am prepared to accept that, though the evidence for it is not yet stable. But, as we all know, "absence of evidence is not evidence of absence." The idea of a quartz bone appeals to me.'

'Stupid of me not to think of that,' said Meg. 'Tut.'

'Carbon, however, is more adaptive. Which is why we're more than soggy bags of electrolytes. Am I boring you, am I?'

'You are not boring me,' said Meg. 'You're more fun than living with a library. Stone bone. I like that. It sounds right.'

'Your library's far bigger,' said Colin. 'And much better looking.'

'Oh, flattery, flattery,' said Meg. 'Stone bone. Bone stone. Mm.'

'Let's see, now.' Colin switched the torch back on. 'What have we here?'

One side of the adit was lined with wine racks. Colin moved along the rows of bottles.

'I think this one,' he said. 'And this. Ah, and I hadn't thought of these. They'll do nicely.'

The adit was straight, and from the end the day showed as a nimbus of another world.

'And while we're here-'

'Colin, we can't drink this much. We'll be paralytic.'