The freedom of the skies! How she wanted it. Tiaan bit down on those feelings. 'Maybe so, but all the cleverness of the Aachim has failed to uncover that secret.'

'Perhaps they were looking in the wrong place.'

'What are you up to, Malien? Do you hope I will solve it for you?'

Malien laughed, though it had an odd ring to it. 'My adventuring days are well behind me.'

They returned to the machine. 'What I don't understand,' Malien continued, 'is how how they could have rebuilt it. I saw Yggur's blast pa.s.s across the void and turn Rulke's construct into a glowing cinder. We all did, who were there that fateful day. How could they recover its design after such ruin?' they could have rebuilt it. I saw Yggur's blast pa.s.s across the void and turn Rulke's construct into a glowing cinder. We all did, who were there that fateful day. How could they recover its design after such ruin?'

She answered her own question. 'Metalmancy. They used mancery to recover the form and purpose of every part of it. That must have been a labour indeed, though they had two hundred years to do it, and the resources of a world. But even metalmancy could not have recovered the most fragile parts.

'They never saw it used,' Malien mused. 'Not the way I did. Rulke's machine was as hot as a furnace beneath, after it had flown.'

'The Aachim constructs weren't hot,' said Tiaan. 'They pa.s.sed over snow and ice without melting it.'

'Did they now! Vithis can't have discovered the secret of flight at all.' Malien turned away. 'I'm going back to check on the Well.' Vithis can't have discovered the secret of flight at all.' Malien turned away. 'I'm going back to check on the Well.'

Tiaan, consumed by the thought of flight, the ultimate secret, hardly noticed her going.

She spent all the following morning practising with the construct, bringing hand and eye into coordination. It was more difficult than it seemed, especially under the pressure of time, though after a couple of hours she could manoeuvre it without too much risk.

She went back over everything the Aachim had taught her of geomancy. The more she compared that to what Nunar's book had taught her, the clearer it was that someone was wrong. The construct did not seem designed to detect, much less draw upon, the strong forces. It used a weak field she had never bothered with.

A few hours later, Malien came down the stairs, exhausted. Tiaan told her what she had learned. 'Maybe Nunar was wrong, and the strong forces do not exist.'

Malien sat on a carved bench and closed her eyes.

After several minutes, Tiaan said, 'Malien?'

'What? Oh, give me a look at the book.'

Tiaan showed her the pa.s.sages in The Mancer's Art The Mancer's Art.

Malien looked thoughtful. 'I think I know how to test your theory. Wait here.'

She returned with two sheets of a gla.s.sy mineral somewhat like mica, though brittle. Laying one sheet over the other, she held them up to the light and rotated the top sheet. At one point it went black. 'Make yourself a set of goggles from these. Put the goggles on, then use the amplimet to envision the field.'

Tiaan did so, and as soon as she put them on, the field streamed all around her.

'Rotate the upper lenses until they go black,' said Malien. 'Now what do you see?'

'Nothing. The field has completely disappeared.'

'Nothing at all?'

'No.'

'Concentrate, as though you're searching for a distant field.'

'Still nothing.'

'You're too tense. Relax. Just let it flow.' Malien's hands went around her head, over the goggles.

Tiaan tried to relax. One of the lenses moved, allowing in a multi-coloured loop of the field. She moved it back to the dark position and saw a white-hot cross made of three planes intersecting at right angles. She cried out, the lenses slipped and the cross vanished. And then the truth came to her.

'I saw it!' she cried. 'The strong forces do exist.' Tiaan began to laugh.

'What is it?' Malien said, anxiously.

Tiaan took particular pleasure in telling her. 'Vithis can't can't be using the strong forces. The Aachim don't know how.' be using the strong forces. The Aachim don't know how.'

'I don't understand. Come, sit down. Tell me what the matter is.'

'The Aachim always act so superior. To their mind they are are superior, and make sure everyone knows it. Yes, you too, Malien. But they're not even using the node field, just little local fields.' superior, and make sure everyone knows it. Yes, you too, Malien. But they're not even using the node field, just little local fields.'

'Stress-fields,' Malien said crossly. 'They're strong on Aachan but weak here.'

'They don't know as much as we do,' Tiaan chortled.

'Beware pride!' snapped Malien, nettled.

'Or false false pride,' Tiaan retorted. 'The Aachim could never have made the construct fly. Flight requires power that only the strong forces can provide, as well as the ability to see them.' pride,' Tiaan retorted. 'The Aachim could never have made the construct fly. Flight requires power that only the strong forces can provide, as well as the ability to see them.'

'Once the secret is out, they will soon learn. So, are you saying you can make the construct fly?'

'I'm prepared to try.'

'Try very hard.'

'Is something the matter?'

'The amplimet is still communicating with the Well, in spite of all my efforts. The Well is drawing power from somewhere and rapidly unfreezing. I can't allow that to happen.'

'What are you saying?'

'Either the amplimet leaves here, or I'll have to destroy it, whatever the consequences.'

TEN.

'No!' cried Tiaan. 'You can't.' 'Do you think I want to?' said Malien. 'No one knows better than I do, how precious it is. I know what destroying it would do to you, too. But should the Well unfreeze and break the bonds that hold it here, the consequences would be catastrophic.'

'How do you mean?'

'Possibly, no more Tirthrax city or or mountain.' mountain.'

'How long do I have?'

Malien hesitated. 'I've sent a skeet to Sta.s.sor, but no Aachim could get back here in less than two months. The construct would be no quicker the country is too rugged for a hovering craft. But with flight, it could be there in a week. I sense that we're close to uncovering the last secret of the construct. Dare I risk it? Come upstairs. I'm going to my eyrie. I need to think.'

Tiaan followed. Malien walked out the opening and stood staring down at the glacier. Tiaan watched, hoping and praying she would come up with something. Destroying the amplimet would surely drive her insane. To miss the chance of flight would be almost as bad.

Malien came running back, her cloak flapping behind her. Tiaan held her breath.

'You have until tomorrow,' said Malien. 'I believe I can hold the Well that long. If you haven't found the answer by then, we must come to a decision: to take the amplimet away, or destroy it. And I dread what will happen if it leaves here whose hands it will fall into. The choice almost makes itself.'

'Please,' said Tiaan. 'I'll take it. To destroy it would be to destroy myself. Though I don't know where to go.'

'In that case, I may have to come with you. Get to work and I'll do the same, and tomorrow I'll decide what is for the best.'

Tiaan studied the strong forces through her goggles. She had to know them perfectly before she could tailor the controller to them, and even then they would be deadly.

The hours raced by. She felt that she was making no progress at all. Malien came and went a number of times during the day, looking ever more careworn. Time was running out.

'No luck?' she asked that night.

'No.' Tiaan was exhausted too, but that was due to her own failure. 'How about you?'

'It's holding, for the moment. Let me have a look down below.' Malien went down into the construct. A good while later she came up with the black box in her hand. 'This surely has to be the key.'

'It isn't connected to anything.'

'The original must have been.'

'Then why didn't the Aachim's mancery reconstruct it?'

'Perhaps the vital parts were no longer there.' Malien seemed to be looking right through Tiaan to the far wall. She often appeared lost in another world, or a distant time. Or perhaps she was holding holding the Well from afar. the Well from afar.

'I have no idea what you're talking about,' said Tiaan.

'I hardly know myself. I'm thinking as I go. The original construct was destroyed by Yggur's blast '

'Completely?'

'There's little in a construct to burn, but its parts would have fused. The crystals commonly used in the Art would not melt, though they may have shattered. Traces would remain, enough for Aachim metalmancers to reconstruct what was there. And yet ...'

'What?' said Tiaan.

Malien looked frustrated. 'I don't know. Rulke's construct flew. These are as exact copies as could be made, but they cannot fly. What did Vithis miss? What have I?'

Tiaan prised the top off the black box, which contained metal coils and shaped pieces of magnetic iron, as well as a number of evenly s.p.a.ced ceramic plates on which were mounted rows of metal sockets. She held the box up to her eye. 'There are dozens of tiny little holes in the back.'

Malien raised the box to the light. 'Fifty-four of them. I wonder what they're for?'

'Perhaps it gets hot inside and they let the hot air out.'

'They're too small.' Malien counted the metal sockets. 'Also fifty-four pairs. That can't be an accident.'

'They're meant to hold something.'

'Whatever it was, all were the same size and shape.'

'Small crystals?' Tiaan said doubtfully.

'How could small crystals draw such power that the construct would grow red-hot beneath? And why was no trace found of them?'

'There are crystals that, when heated, simply evaporate, though none are any use in mancing ...'

'That's it! Tiaan, name those crystals.'

'Ice, sulphur, iodine ... There must be others, but none are good for making hedrons '

'Some mancers use brimstone crystals.'

'Not for drawing power. It would shatter them.'

'Agreed. What else?' Malien leaned forward eagerly. 'What is the most powerful crystal?'

'Diamond, of course, but diamonds are generally too small to use in controllers. And large ones are too precious.'

'Not if they're the only thing that will do,' said Malien. 'And Rulke had the best of everything.'

'But diamond is the hardest of all. Why didn't they find it?'

'Because, unlike other crystals, diamond burns. That must be the answer: these pairs of sockets once held small hedrons made of diamond.'

'How were they connected to the amplimet binnacle?'

'Perhaps through these tiny holes in the back, no bigger than a cat's whisker? And look, there are also fifty-four holes in the back of the amplimet cavity.'

'If they were connected to the crystal there, why did metalmancers not recover the wires?'

'Because they were not metal, and also vanished without trace.'

'How can that be?'

'What wires would disappear when heated, Tiaan?'

'Ones made of thread, or spider-silk, or hair, though none are useful in the Art as I know it.'

'Nor I. Wait here.'

Again Malien disappeared in the direction of the storeroom. She was gone for ages. It was after midnight. Tiaan lay on the warm floor of the construct. Only hours left ...