THE INVERTED WORLD

 

Christopher Priest

 

 

On our world if you stand in one place long enough you will find yourself in exactly the same place. The trouble for Future as well as for Gerdun Mann was to keep the city of Earth in that one spot and this could only be done at the cost of enormous effort by continually moving. There is much of Christopher Priest’s enigmatic reaction to life in this infinite world he envisages existing outside the parameters of the known and familiar.

 

* * * *

 

One

 

Gerdun Mann was on the Moon when they located him. He was working with some other reconstruction technicians on the remains of the Apollo 11 equipment, which had been unexpectedly wrecked by a moonquake. The first Moon landings still had a nostalgic value for tourists from Earth, and the necessary reconstruction work was slow and painstaking; the original site was now too badly damaged for re-erection of the repaired descent-stage, and the whole assemblage was being moved nearly a mile to the south. Mann was in the final stages of carefully duplicating—from photographs taken at the time—all the footprints and pieces of litter left by the original astronauts.

 

At the end of his shift, Gerdun drove to the temporary hostel built near the new site, took off his work coverall and life-supports, showered, ate a meal and prepared to relax for a few hours before returning to finish the work.

 

Gerdun Mann was a reader. There were still a few firms who printed books, catering to what was seen as a fashionable whim by a small but affluent minority. Words printed on paper were still available for those who cared to seek them out, but they were in short supply on the Moon. Once Mann had estimated that he had read everything that existed on the Moon, and that day had taken out a subscription with a firm on Earth. It was his one luxury, and he rejoiced in it. He still had seven of the books from his last consignment to read, and now he went to his room to read the last few chapters of Dombey and Son. He desired nothing more at that moment than privacy and solitude, and sufficient mental energy to finish the book before he fell asleep.

 

He was aware, about an hour later, that a craft had landed near the hostel. He ignored it. He was also aware of somebody entering the hostel, and he tried to ignore that too, even as a growing certainty in him warned that his privacy was about to be invaded just as surely as his concentration had been. He sighed, and closed the book as someone knocked on the door.

 

It was Fitzpatrick, his immediate senior.

 

Gerdun invited him into the tiny room, noting that the man had not removed his surface-gear.

 

‘I’m off-duty,’ he said. ‘I’m tired, and I’m reading.’

 

‘And I’m sorry. I didn’t come two hundred miles for nothing.’

 

‘That’s what I thought. Don’t tell me, you want the module moved to another site.’

 

Inside his helmet, Fitzpatrick grinned and shook his head. ‘Not this time, no. I’ve got something for you.’ He turned his back on Mann, ‘In the bottom compartment... a package.’

 

Mann opened the compartment in the back-pack and took out a small, plastic-wrapped carton.

 

‘What is it?’

 

‘You’ve been recalled to Earth. I’ve issued an authorisation, and-’

 

‘What? But I don’t want to go to Earth!’

 

As well as a man in a life-support suit can shrug, Fitzpatrick shrugged. ‘Someone there wants you to go. I gather it’s important.’

 

Gerdun Mann looked at the package in his hand. He had lost all desire to open it.

 

‘Listen, Joe, there isn’t a single good reason why I should go to Earth. I don’t want to go, I don’t have to go. I’ve got a contract here that runs for another three years. I don’t know anyone on Earth, and no one on Earth knows me.’

 

‘They’ve apparently found a good reason. There’s a relative they want you to meet.’

 

Mann stared at him with a healthy malice, then opened the packet with deliberate motions. ‘I don’t have a single relative alive on Earth...’ He took some papers from the packet, and looked through them.

 

‘They came on the last shuttle,’ said Fitzpatrick. ‘I was radioed about them this morning, and had someone pick them up for me. Don’t ask me what it’s all about, because I don’t know. I was told by EASA that they were top priority, and that you were to return to Earth on the same shuttle.’

 

Gerdun Mann was staring at one particular piece of paper which was written in the familiar—though to Mann, abhorrent—combination of monosyllables and graphics that passed for contemporary written English.

 

‘“Department of Transliteral Geophysics”?’ he said. ‘Have you ever heard of them?’

 

Fitzpatrick shook his head. ‘Have you seen the names on the masthead?’

 

‘That is what’s interesting. They want me on Earth, without telling me why.’ He looked suspiciously at Fitzpatrick. ‘What was this about a relative?’

 

Again, Fitzpatrick made the awkward shrugging motion. ‘It was just something they said on the radio. It may have been a joke.’

 

‘Joe, I don’t want to go. I enjoy the work and I enjoy the life. I’ve no ties on Earth. Give me a single good reason why I should go.’

 

Fitzpatrick stared round the tiny cubicle, and noted the hundreds of volumes jammed into every available space.

 

‘Have you thought about the British Museum reading-room?’ he said.

 

‘There is that,’ said Mann. ‘Maybe I’ll go.’

 

* * * *

 

The atmosphere of crisis which had pervaded the city of Earth for the last few miles had not eased at all as Future Mann set off on one of his regular reconnaissance missions. He was not sorry to leave the city at this moment, for he, like everyone else was deeply involved in the trouble. The whole existence of the city was threatened, and so were the lives of everyone who lived there. At least Future had been given the opportunity to escape from the apprehensions for a while, and for this he was grateful.

 

Even so, he was faced with the regular dangers of his work, and he was not unaware of these.

 

He left the city, and headed north. There was only one direction in which his work took him, and it was always north. He rode his horse carefully, sensible of the fact that she was one of the seven beasts left. She had not foaled this year, and unless another wild herd was encountered soon this too would bring another small crisis to the city.

 

He rode slowly alongside the rails, nodding to each of the Militiamen who stood on guard. The rails were one of the two most vulnerable aspects of the city, and they had to be guarded night and day. It was these and the cables that the enemy attacked. Today, in the wake of a relatively long period of peace—three miles had elapsed since the last attack—Future noted that the Militiamen were uneasy, that if anything the feeling of impending attack was greater here than in the city.

 

He rode for another half-mile until he came to the present cable-stay emplacement, and checked-out with the controller, Cable Statchik.

 

‘How far are you going?’ said Statchik.

 

‘Seven, maybe eight miles. I hope to be back tomorrow. Routine north-survey.’

 

Statchik nodded. From where they were standing they could see back to the city. Already, at this short distance from Earth, the concave nature of the gradient could be seen. They looked back along the straight path of the rails, saw the three six-inch wound cables taut under the strain, disappearing under the front lip of the city to where the nuclear winches slowly wound them up. Looking at the cables always made Future nervous. He knew of the time when one of them had broken and whipped back into the heart of the city, killing eight men and injuring dozens of others.

 

Looking beyond the city to the south, Future could see the rail-teams dismantling the track, loading the sections on to sleds and preparing them to be hauled slowly to the north of the city where they would be re-laid once more. As Earth city moved itself forward, once again those rails would be behind the city, and once again be taken up and brought round to the north side. And at the same time the cables would be extended further and further to the north, planted in another emplacement like this one, anchored to the ground by deep, steel piles.

 

Allowing his gaze to move even further to the south. Future Mann saw the ground the city had already passed over, spreading up and out behind the city, moving up in an apparent gentle slope ... up and up until it was lost in the atmospheric haze. Standing here, away from Earth city, it was possible to witness the immense size of the world, even if the mind could not encompass the concept. Further north, in the region he was about to travel, the phenomenon was even more marked. As he walked the future ground, the country he had left would rear up behind him like a wall. It took a special kind of man to survey the future, for the distortions of apparent dimensions were immense.

 

So it was with a mutual respect that the two men regarded each other. Mann, for he could not bear close proximity to the cables for long, and Statchik, for this far into the future was enough for him.

 

Future Mann remounted his horse, nodded to Cable and set off on his survey-mission.

 

* * * *

 

On his way to the hospital, General Dula stopped by at the temporary field-headquarters.

 

‘Where’s Gerdun Mann?’ he said as he walked in to the office. A young major sitting behind a desk jumped to his feet, saluted, then relaxed as Dula nodded to him.

 

‘He’s on his way, sir. We had difficulty locating him.’

 

‘Where was he?’

 

‘On the Moon, sir, working with-’

 

‘On the Moon? How long before he’s here?’

 

‘He’s coming immediately. Three days for the flight, and another to reach here.’

 

Dula frowned, and walked over to inspect a map pinned to a wall. He stared at it thoughtfully for a few minutes while the major waited.

 

‘Is there a problem, sir?’

 

‘Of course there’s a problem. Time’s the problem. We haven’t got enough of it. By the time Mann’s here and we’ve briefed him it’ll probably be too late. Even then, he may not want to do it. He’s a civilian.’

 

‘We could send in another detachment.’

 

‘That’s what I’m thinking. How’s the supply situation?’

 

The major glanced at some papers on his desk. ‘I’ve contacted Geneva, sir. They can get a dozen more suits to us by this evening.’

 

‘OK. Tomorrow we have another go. I don’t like it, but there’s no alternative.’

 

He turned and walked out of the headquarters. His car was waiting outside.

 

General Dula spent an hour at the hospital, talking to the troops who had been wounded in the previous confrontations. As general in an army unused to fighting, he wasn’t accustomed to having men injured, far less to having them killed. So far, the operation had cost the army eleven men killed, and another fifty or so wounded.

 

Later, he returned to the HQ to plan the following day’s operation.

 

The suits arrived that evening, as promised, and Dula tried on one himself. Trying to walk wearing it was difficult, and the idea of a man defending himself inside it was almost inconceivable. The very weight of the equipment was prodigious, and the fact that most of that weight had to be carried on the back made movement and manoeuvrability difficult.

 

In the privacy of his own office, the General walked up and down for a few minutes, coming to realise that as the next day’s operation was probably the last attempt they would have, he was going to have to go in personally. That much at least established, he took off the suit under the anxious eye of the civilian technician and called a meeting of his staff officers. Later that night he attended a committee, comprising several members of the Department of Transliteral Geophysics—including Mosta Langham, the Director—his GOC, two representatives from the firm in Geneva producing the transliteration equipment and a handful of civilian advisers. Dula disliked committees in any event, and reserved a special dislike for committees which pressured him. He was being pressured now, and, he suspected, being eased out.

 

When General Dula went to bed that night he was tired, irritable and very worried.

 

* * * *

 

At this point eight miles north of the city, sunrise came early. Future Mann had spent the night near the bank of the river, and was awake a few minutes after daybreak. He came out of his tent, saw that his horse was standing patiently nearby and began to make preparations to move back to the city. At the present latitude the days were hot, and he wanted to be back in the city by midday. When he had eaten some food, and stowed his equipment in the saddlebag, he glanced at the sun, shielding his eyes with his hand.

 

Though still low on the eastern horizon, and diffused by the atmosphere, the sun was a brilliant-white cross that threatened to blind anyone who stared at if for more than a second. The upright arms of the cross were as thin and spindly as they had ever been known, but the lateral arms were broad. Future had seen ancient drawings of the sun when it had been a thin, cool rood, but gradually the lateral arm had thickened so that mile by mile the climate had become warmer.

 

There was no question in the minds of the people of the city but that as Earth continued to move north the temperatures would continue to mount. This was no concern of Future’s; he left such problems to the city Navigators.

 

His own problem was before him, beginning a few yards from where he stood and spreading as far north as his eye could see: the river.

 

The city had crossed rivers before, and although they introduced a new element of danger to the people of Earth, the history-books were full of the accounts of heroic crossings. There was even a Guild in the city whose sole function was to organise the traverses of such obstacles: the Bridge-Builders. Some of the greatest men in the whole history of Earth had been members of this Guild.

 

But never before had there been such a river as this.

 

Future Mann’s survey had been ordered to verify the first account of the river from another Surveyor, Future Blayne. Blayne’s account had been so unexpected, so incredible and anyway so unwelcome at this time of crisis that the Navigators had discounted it.

 

There had never been a river too wide to cross. There had always been an opposite bank, always a promise of a return to solid ground.

 

‘In Future Mann’s own Guild—the Future Surveyors—an account by one Surveyor was taken as indisputable. But Blayne had been a Surveyor for only a few miles, and was relatively junior in the Guild. For sake of protocol, Future Mann’s expedition had been said to attempt to find an alternative route from the one Blayne had surveyed, as this was an acceptable motive for a re-survey.

 

Privately, however. Future Mann had been ordered by his Guild Leader—Future Constant—to check the nature and, perhaps, the existence of the river.

 

So now Mann stood on the very bank of that river, witnessing with his own eyes the appalling breadth of the water. Using his Surveyor’s eyeglasses, Mann tried again to find the opposite bank. He searched to the very limit of his vision, but could see no sign. Forty, perhaps fifty miles or more at least until haze and cloud obscured everything, and no certainty of firm ground even at that distance.

 

It was more than his mind could grasp. The widest river in all history had been only one and a half miles across, and that had stretched the ingenuity of the Bridge-Builders to its limit.

 

In the city, the Guild Leader was waiting for his report, and a special meeting of the Navigators was waiting to be convened in the event of his reporting positively.

 

Future Mann was in no position to waste time. After one last look at the river, he mounted his horse and set off southwards.

 

There was no alternative but that the city had to cross the river. It was the very nature of the continued existence of the city that it had to move north. Its path would bring it, in eight miles time, to this water, and without hesitating it would have to continue its journey. In that period, a bridge would have to be planned and built, ready for the day when the tracks ended and the water began.

 

Future’s horse was well rested after the night, and he kept her at a steady canter across the low countryside in the immediate hinterland of the river. Further south, there was a range of hills, and he walked her up the incline. At the top, he paused, and stared south.

 

The land spread up before and in front of him. He glanced up, trying as a hundred Surveyors had tried before him to see the Equator ... but although the heat-haze of the day was still thin over the land he could see no more than one or two hundred miles. He shook his head. Surveyor or not, his mind was only a human one, and it was not wide enough to accept the concept that it was theoretically possible, and literally so, to see forever.

 

He stared down at the ground immediately before him, as all city-dwellers did, and rode on in the direction of Earth.

 

His first intimation that an attack was under way was when he approached the cable-stay emplacement. There were no Cablemen in sight, and the usual signs of activity around the city were absent. Future could see that the Militiamen had been reinforced, and now they stood in a firm defensive line alongside the track.

 

Only the tautness of the cables indicated that the winches still turned. Still the city inched itself forward along the track ... never able to stop, never able to alter its direction from a heading of due north.

 

Someone in the cable-stay emplacement must have seen him, for a few seconds after he reined in his horse. Cable Statchik came running from the emplacement. He was crouching low, and wearing the heavy leather jacket that was the standard protective garment for those forced to be away from the city during a raid.

 

‘Get back to Earth!’ he shouted. ‘There’s an attack due any moment now.’

 

‘Is it serious?’

 

‘The biggest yet. Thirty or forty of the monsters ... over there!’

 

Statchik waved his hand in a westerly direction, and Future Mann looked that way. Sure enough, a few hundred yards to the west of the city he could just make out a group of small black figures, walking with the ungainly tread of the raiders towards the track ahead of the city. One walked slightly before the others, carrying what appeared to be a large white sheet.

 

‘That damned sheet,’ Mann said. ‘What does it mean ?’

 

‘It’s a banner,’ said Statchik. ‘It’s a signal to the others to attack.’

 

‘Do they always wave it?’

 

‘Every time there’s been an attack. Come into the shelter. Quickly! You’ve got only a few seconds.’

 

Future had not dismounted, and he looked anxiously at the city. It was nearer to the emplacement than it had been the last time he was here, and he was trying to estimate how long it would take the horse, at a full gallop, to cover the distance.

 

‘I think I’ll try to get back,’ he said.

 

‘You won’t make it.’ Statchik reached up for the bridle of the horse, as if intending to lead it towards the shelter.

 

‘No,’ said Future. ‘It’s too important. I’ve got to try.’

 

He dug his heels hard into the horse’s flanks, and she galloped forward. Statchik leapt out of the way, fell, then half-stumbled, half-ran towards the safety of his shelter.

 

Future paid no attention to him, knowing that if the attack could be rebuffed again the man would be safe enough in his shelter. His main preoccupation was to return to the city and report to Future Constant. What he had to say was too urgent to be delayed.

 

As the horse galloped towards the city, Future glanced in the direction of the raiders. They were spreading out, adopting the pattern from which they always attacked.

 

He looked ahead, saw that the Militiamen were ready. The front line had their crossbows armed, and aimed.

 

Suddenly, Future Mann realised that by an error of judgment, caused by his haste, his intended path was going to take him between the Militiamen and the raiders and that he would be caught in the cross-fire.

 

He was already past the first of the Militiamen, and one of the officers shouted at him to get out of the way. Directly behind the line of men was the nearest cable. With no time to make fine decisions, Future swung his horse to the left, rode between two Militiamen and headed directly for the cable. It was about five feet from the ground. At full gallop, the horse jumped.

 

One of her rear hooves touched the cable, and as she returned to the ground she stumbled. Future tugged savagely on the reins and managed to keep her on her feet. For two seconds he applied no direction to her, allowing the horse to find her own balance ... then again he kicked his’ heels into her sides and she continued her gallop towards the city.

 

An order was shouted and all down the line the front Militiamen loosed off their bolts. Well-disciplined, they stepped back and the second rank moved forward while the others reloaded. Future spared a few seconds to look over at the raiders, and saw that only one of them had fallen.

 

Even as he looked, there was a burst of explosions, and several of the Militiamen fell. Now directly under fire, Future concentrated on his dash.

 

The horse was running between one of the metal tracks and the cable. Crouching low in his saddle, Future urged the horse to greater speed, seeing that the city was looming up ahead of him.

 

When he was ten yards from the front edge of the city, the second line of Militiamen loosed their bolts. Future had no time to see the results, for then he was under the city, riding in the dark and quiet, only the eternal creaking and groaning of the winch-drums disturbing the peace. He slowed his horse, then walked her to the bay which led up to the stables. She smelt the other horses, for now she was calm, even though breathing heavily from the gallop.

 

After entrusting the mare to a stable-boy. Future Mann made his way up to the main platform of the city, first to present his report to Constant and then, if necessary, repeat his message to a full convention of the city Navigators.

 

* * * *

 

Two

 

The day that Gerdun Mann arrived in Europe from the Moon, all military operations were stopped. Mosta Langham, the current Director of the Department of Transliteral Geophysics, had a private consultation with the GOC land forces, and General Dula and his men were withdrawn temporarily. The last expedition into transliteral country had ended badly—two men killed, another five injured— and it was now clear that there was no solution by military means. Like Dula, Langham was only too aware of the lack of time, and he was no more pleased at the withdrawal than Dula. No army likes to be withdrawn before it can succeed.

 

Gerdun Mann had been delayed. The shuttle from the Moon had landed him at Kennedy, and Langham had ordered that a private craft be waiting to bring him direct. Instead, Mann had taken a scheduled flight to London, and DTG agents had had to track him down again. He was on his way now, and Langham left instructions for him to be brought to the transporter as soon as possible.

 

With nothing more to do until Mann arrived, Langham went to the transporter and stared at the screen. Now that Dula’s men had retreated once more, there were signs of activity around the station. There were more armed men than ever before around the cables, and when a small party of people left the station and walked across to a grove of wild olive-trees to pick more of the fruit, they were accompanied by several crossbow-bearing men. They stayed away from the station long enough to pick only a few baskets of fruit, then returned in some haste to the station.

 

Langham moved from the screen and went outside.

 

There, only a few hundred yards from where he stood, was another olive-grove, identical in almost every way to the one he could see on the screen. But, beyond it, no station.

 

He heard the sound of an engine and looked up into the sky.

 

Shielding his eyes against the sun, he saw a helicopter coming towards him, and a minute later it landed a few yards from where he stood. A tall young man, carrying a suitcase and a large parcel, was helped down from the craft by two other men. Langham walked across to meet him.

 

‘Are you Gerdun Mann?’ he shouted over the noise of the aircraft.

 

Mann gave his suitcase to one of the two men, and walked unsteadily towards him. ‘That’s right.’

 

‘Mosta Langham. I’m Director of the Department.’

 

‘Help me, will you ? I’m not used to the gravity yet.’

 

Langham took the man’s arm and assisted him towards the transporter. He offered to take the parcel, but Mann shook his head and said he was all right. Behind them, the agent who had come from London with Mann walked with the suitcase. Langham noticed that Mann was wearing clothes totally unsuited to the climate and realised he must have come straight from London without an opportunity to change.

 

When they were inside the transporter, and the agent had returned to the helicopter, Langham said: ‘Would you like to go to your hotel to wash and change?’

 

‘I’m all right for the moment. I understand there was an element of urgency in this visit.’

 

‘That’s right,’ Langham said. ‘It can wait another hour or so...’

 

Mann shook his head. ‘I assure you, I’m not uncomfortable. I rather enjoy the heat.’

 

Langham regarded him, saw that he was wearing at least three layers of clothes, and concluded that it must be colder on the Moon than he had imagined.

 

‘Very well. The situation is urgent, and the sooner we resolve matters the better. Everyone here is very grateful that you were able to come so promptly.’

 

‘Do you mind if I sit down ?’

 

Langham pointed to a chair in front of the screen console. ‘Sit there ... please. This is what we’ve brought you to see.’

 

He switched on the screen, and Mann sat down. As the image resolved, Langham turned a control and selected a wide-angle view of the station and the surrounding countryside.

 

Without further explanation, Langham called in two of his assistants from the motor-compartment of the transporter, dialled four cold drinks from the dispenser and made mental preparation—for perhaps the tenth time that day—to explain in simple terms a concept and situation that had threatened to dismay the finest brains in his own highly-specialised field. He didn’t think he could do it.

 

* * * *

 

The Council of Navigators was the only kind of government in the city of Earth. It had a tradition of being badly attended, but in the recent miles of crisis every session had been almost fully attended. Futures Constant and Mann had presented their report, then left. Now the Navigators had to agree on how they should act on that report.

 

‘There can be no question,’ said Navigator Olssen, the president of the Council, ‘that the safety of the city is in danger. We now know that ahead of us lies the greatest natural obstacle the city has ever had to confront: a river so wide that we cannot see its opposite bank. There is no doubt in my own mind that we have to cross it. I believe that all there is to discuss is how.’

 

Olssen sat down, and as he had privately predicted, Navigator Jase got to his feet. Jase was the youngest of the Navigators currently in council, and had affiliated himself, in spirit if not in fact, to the movement in the city known as the Terminators.

 

Jase’s speech was long and portentous. To Olssen’s mind he covered no new ground, but in effect restated the philosophy of the Terminators: there was no apparent purpose to the city’s continued journey northwards. Every mile the city covered revealed new threats to their existence. There was the fact of the gradual rise in average temperatures, the continuing threat of the raiders, the abundance of good soil and vegetation in this region. Now there was a new hazard in the form of this river. The time had come, Jase stated firmly, to turn off the winches for good, to let the tracks rust and the cables fray.

 

He sat down to a spattering of applause from a few of his supporters.

 

The traditional opposition-speech out of the way, Olssen called on Bridge-Builder Lerouex to list the possibilities. Lerouex was in attendance in an advisory capacity. An old friend of Olssen’s, he was in line for a Navigatorship and had realised that he was now presented with an engineering task of a magnitude no Bridge-Builder before him had ever had to face. That morning he had ridden north with Future Constant and seen the river for himself.

 

After the customary compliments paid by an advisor to the Council, Lerouex got down to details. He addressed the president directly.

 

‘Navigator Olssen, as you know we normally employ one of two methods for crossing stretches of water. The first is by erecting a platform from one bank to the other, on which the tracks are laid. The other is to construct a pontoon bridge, which floats directly on the water. My Guild would normally advise the latter for wider stretches of water, but in this case I fear that it would not be possible. The reason for this is quite simply that either method of river-traversing requires the cables to be implanted on the opposite bank to provide traction. I have seen this river for myself; it is so wide that I assure you that even if we could locate the opposite bank we do not have cables long enough to reach it.’

 

‘Then what do you propose?’

 

Lerouex shrugged.

 

‘I see no solution,’ he said. ‘At least, not in terms of a bridge. It occurred to me this morning that the only possible way of crossing this water would be to convert the city into a ship ... and of course this could not be effected in the time we have available.’

 

A short silence followed this statement, the Council appreciating that, in effect, the Guild of Bridge-Builders was admitting defeat.

 

Once more, Jase rose to his feet, and pointed out that Lerouex’ statement only lent weight to his point of view.

 

As Jase sat down again, Lerouex walked out of the chamber. He knew it was an affront to the Council, that Olssen in particular would be offended; but he saw that he had nothing more to add.

 

He sought out Future Mann, and found him at the rear of the city, facing south, staring into the distant past.

 

Mann said: ‘What was the decision?’

 

‘I don’t know. I left before the debate really began. I said all I could.’

 

‘Which was?’

 

‘That we cannot build a bridge.’

 

‘That’s what I thought, but felt it was your decision to make.’

 

Lerouex stood beside him, and together they stared down at the ground moving slowly below.

 

‘I think I know what will happen,’ Lerouex said in a moment. ‘The Council will decide to build a bridge. They will want a pontoon bridge, and they will try to convert the traction of the city from winch-power to direct drive.’

 

‘Would that work?’

 

‘It’s been done before. Many miles ago. But the bridge itself wouldn’t work. No one can build a bridge that long. Not in the time we have. Not with the facilities we have.’

 

‘Suppose they decide to ?’

 

‘Then I will resign.’

 

Mann looked at him in surprise. ‘Do you mean that?’

 

Lerouex nodded. They stood in silence for a long time.

 

‘I’m not a Terminator, you know,’ said Lerouex eventually. ‘I know that the city must move. We cannot stop. Everything we live for depends on our continued ability to move northwards. I fear what would happen if we stopped. Our Guild is one of the oldest in the city. The first Bridge-Builder knew Destaine.’

 

‘I didn’t know that.’

 

‘It’s true. Destaine was killed very soon after the city was built. Shortly before he died he wrote the Directive, and it was to a man called Thannet that he gave it. Thannet was the founder of my Guild. Destaine’s Directive says that we cannot stop, that we must not stop. Nothing must interfere with progress. If we encounter water, we cross it. If we come to a range of hills, we climb them. If we come to a deep chasm, we go round it.’

 

Future Mann said: ‘But what if we didn’t ? What would happen if we stopped?’

 

Lerouex looked south, across the plain to the range of hills they had come through a few miles before. Behind the hills, rising up, was the low countryside beyond.

 

‘I think we will discover that shortly. The city will have to stop. It cannot cross that water. We shall have to turn off the winches, and if the raiders do not kill us all then gradually the movement of the ground will take the city southwards. Very surely, we will be borne towards the equator. When that happens, the city will be destroyed and everyone on it will be killed.’

 

Future Mann frowned. He did not care to think about the city not moving. Every child born in the city was brought up with the over-riding teaching that the city must always move.

 

Later that day, the decision of the Council was announced. The city would not stop. A bridge would be built, and it would be a pontoon. Work would commence immediately. The winches would be converted. The northwards journey would not be interrupted.

 

So Lerouex’ prediction was accurate ... but he did not wait to learn the consequences. An hour after the decision was announced, he formally resigned from the Bridge-Builders’ Guild, and the following morning was found dead in his room. He had shot a crossbow-bolt into his own mouth.

 

* * * *

 

Gerdun Mann opted for an early night, and was conducted courteously to his hotel by Langham in person. He ate a good meal, undressed and showered. He got into bed, and opened the parcel of books he’d purchased in England. For a while he sifted through them, luxuriating in the white newness of the pages, the firmness of the bindings, the smell of recent glue in the spines. At length, he selected one and settled back to read it. He got through the first chapter, then put the book aside. For the first time in longer than he could remember his attention was distracted away from a book.

 

He was thinking of what he had seen through Langham’s television scanner. Thinking of a world that was so like Earth—and in some senses was Earth—and yet totally strange. A mathematical abstraction of a planet that had the same volume as Earth, but possessed what Langham assured him was a surface-area of infinite size. Literally ... infinite.

 

‘But is it real?’

 

‘If you can believe what you see, then it is real.’

 

A planet with north and south poles at infinity that didn’t revolve at all, and an equator which revolved at infinite speed.

 

‘But nothing can move faster than the speed of light.’

 

‘A sufficiently large rotating disk will have its circumference travelling at the speed of light. This world has an equator of infinite radius, and it rotates.’

 

‘But it’s not a disk.’

 

‘It’s shaped like a hyperbola.’

 

Again and again, Langham had instructed the camera-operator to pan his instrument to and fro. Gerdun Mann had seen the geophysics station—altered and expanded in strange ways—standing on an incline of forty-five degrees.

 

‘That is the point of equilibrium,’ Langham had said. ‘The point at which gravity-stresses are the same as on Earth.’

 

‘They’re on a one-in-one slope.’

 

‘Not there. Gravity homes in on the centre of their world; the equilibrium position is the nearest point on the surface to this centre.’

 

The camera panned to the left, towards the north of this world. The angle of the incline sharpened quickly—from forty-five to sixty, then seventy, then more than eighty degrees—and the resolution of the picture began to dim.

 

‘What’s the matter now ?’

 

‘Atmospheric haze. There ... you can see the water.’

 

Mann looked, saw the faint glimpse of an expanse of water, seemingly flat now against the almost vertical wall of the world.

 

‘Why doesn’t it pour down ?’

 

‘Gravity homes in on the centre of the world, but it also homes in on the axis of revolution. We don’t know how. It causes stresses, and distortions.’

 

The camera panned down and to the right, past the geophysics station and its strangely hostile inhabitants. Behind the station, to the south, the gradient flattened out quickly. Mann saw trees, hills and a small river.

 

‘The ground looks flat there.’

 

‘It is almost flat in our terms.’

 

‘Then why isn’t the station there ? Why is it halfway up the slope?’

 

‘It’s at the point of equilibrium. Gravity homes in on the centre of the world, and on the axis of revolution...and on the plane of that revolution. The distortions are immense, though it would be technically possible for a man to be there.’

 

‘So why isn’t the station there?’

 

‘Because it is safest where it is. Standing near it—as I have done—one feels as though one is on flat ground. If it did move too far to the south, then it would start to feel the effects of centrifugal force. On this world, centrifugal force is a considerable factor.’

 

A planet of infinite radius has its equator travelling at infinite speed, even if its angular velocity is the same as on Earth.

 

‘It rotates once every twenty-four hours. They have night and day. Let me show you the Sun.’

 

The camera-operator slotted a filter into the camera, and the picture darkened. In a moment, a bright cross-shape swam into view.

 

‘That’s the Sun.’

 

Gerdun Mann gaped at it in disbelief. Instead of the brilliant sphere he had imagined, the Sun was shaped like a cross, the lateral arm slightly broader than the vertical.

 

‘That is the same shape as this world?’

 

‘Yes.’

 

‘So it has a radius of infinite size.’

 

‘At its equator, yes.’

 

‘But there isn’t room in the Universe for two objects of infinite size.’

 

‘Not in our Universe there isn’t.’ Langham told the camera-operator to relocate the geophysics station. ‘There’s a Moon too. And planets. And a lot of stars.’

 

‘All of infinite size.’

 

‘I’m afraid so, yes.’

 

For a long time the camera had rested on the geophysics station. Mann had watched this with fascination, seeing the curiously antiquated machine. It had been added to and extended, and was now several times larger than even modern-day stations.

 

‘You can see how they’ve adapted it. The caterpillar tracks have been removed, and the traction is provided by some arrangement with winches. Most of the superstructure has been removed, and replaced with makeshift buildings. You can’t see the tracks clearly from this angle, but there are four of them. The station has wheels beneath it, and these run along the tracks as the winches wind in the cables.’

 

Mann had remarked to himself that it appeared as if the station were hanging on the cables, as if they prevented it from running backwards down the gradient.

 

‘If the cables snapped?’

 

‘The station would stop moving. They’re at the gravitational equilibrium.’

 

‘But the city is moving now. Why?’

 

‘To stay where it is.’

 

Sitting upright in his hotel bed, Gerdun Mann wished that he had stayed where he was: on the Moon. At least there he knew how everything related to everything else, even if he spent most of his time working in brilliant sunlight that would fry him if his life-supports failed, and a vacuum that would suffocate him if he opened his face-plate. That made an unpleasant kind of sense; but what he had seen that day made very little sense at all.

 

‘It stays where it is by moving?’

 

‘That’s right.’ Langham had instructed the camera-operator to zoom in on the underside of the station. ‘It moves very slowly ... about one-hundredth of a mile an hour. The same speed, incidentally, at which this transporter we’re in moves.’

 

For as long as he could remember his own thoughts, Mann had been used to the idea that if one stood in one place long enough one would find oneself in precisely the same place. Now he thought about it, perhaps it was this that made him like the act of reading books. If he stared at a page, it always contained the same amount of information however long he took over it. He could read something twice over, refer back if he wished. The audio-visual devices which were so popular now, though, had no such luxury; they swept you on, never letting you slow down or reconsider.

 

This world that Langham had shown him was like that. The ground moved. It wasn’t like Earth, where everything was solid and permanent; the ground moved.

 

It came down from the north pole, moved towards the equator.

 

It was slow—just over one hundredth of a mile an hour—but it never stopped. Stand still long enough, and you wouldn’t be in the same place. The ground would carry you inexorably towards the equator.

 

‘If the equator is infinite,’ Mann had said uneasily, ‘where does the ground go to... ?’

 

Here Langham had looked worried.

 

‘This is where our knowledge of this situation becomes hypothesis,’ he said. ‘Remember we are seeing only the northern hemisphere—if that is the word—of this world. There is a southern hemisphere too, also hyperboloid. Mathematically, a hyperbola meets its axis at infinity and crosses to a negative value. If this is so, then the ground crosses from north to south hemispheres at the equator, and moves on down to the south pole.’

 

‘And then where does it go?’

 

‘It reappears at the north pole, and the process is repeated.’

 

Gerdun Mann had rediscovered the childhood pleasures of biting his nails.

 

‘You would think nothing of flying around the world,’ said Langham. ‘Fly far enough and you return to your starting-place. The difference here is that the planet does the work for you.’

 

He showed Mann a model of the world that one of the men had built. It was shaped roughly like a gyroscope, with tall thin poles and a sloping disk for the equator.

 

Langham said: ‘At a distance of approximately two and a half thousand million miles from the point of equilibrium the ground is travelling at the speed of light. Beyond that we cannot see it, though it does indeed continue for infinity.’

 

‘The planet has an effective radius of two and a half thousand million miles?’

 

Langham nodded.

 

‘But that’s roughly the size of the Solar System!’

 

‘Of our Solar System.’

 

It was at this point that Mann had decided that he would, after all, appreciate an early night.

 

He lay back on his bed in the Oporto hotel-room, turned off the light and listened to the traffic outside. That was a new enough experience after eighteen months on the Moon. There were a lot of people out there, and that was interesting in itself. He’d like to get used to that idea alone before trying to absorb anything else that Langham could tell him.

 

In spite of his own expectations to the contrary, the man who had travelled a quarter of a million miles to be shown a world whose size exceeded that of the known Solar System slept soundly and without interruption.

 

* * * *

 

Three

 

When the Council of Navigators made a decision, it was implemented at once. The same day that Lerouex was found dead, another Bridge-Builder was nominated as head of the Guild, and work commenced.

 

Future Mann suddenly found himself very busy.

 

There were few men who were accustomed to travelling north, and most of them were Future-Surveyors. Now the route across ground was clearly surveyed there was little work for the Futures to do in the normal way, and they were seconded to working with the Bridge-Builders.

 

The general alert against the raiders was not slackened and the heavy defence-lines of the Militiamen were not weakened in any way. Most of the other people, though, became involved in the new work. Timber was the most urgently needed commodity, and a mile before the present crisis the city had passed a heavily-wooded area. Fortunately, the trees in the region had a high cork-producing nature, and the buoyancy of this substance provided the foundations for the design of the pontoon.

 

Being to the south of the city, the trees were away from the normal point of conflict with the raiders, and the men and women who went out to cut the timber were escorted by only a light guard. More defence was provided for those working in the north, and at the selected place on the bank where the construction work commenced the Militiamen built a small fortress.

 

Privately, Future Mann had his doubts about the efficacy of the project. He had been in the city on several occasions when it had been obliged to cross water ... but never such water as this. That last conversation he had had with Lerouex had worried him; if the city could not go on and was obliged to stop, what then ? Worse, if the city did go on and the bridge was not strong enough, it could founder.

 

But no one could see an alternative. So Future Mann worked with the others. He hauled timber, he sank piles, he waded in the shallows of the river, securing the first pontoons to the shore. He trusted the Bridge-Builders because there was no one else to trust. They had their task, and they had always done it well. But several times Mann heard quiet doubts expressed in unguarded moments, and these began to erode his confidence.

 

At first he attributed these uncertainties to the fact that when men who normally spent a large part of their time in or around the city came this far north the strange nature of the environment often disconcerted them. He, as a Future-Surveyor, spent much of his time in the north, and grew accustomed to the sight of the southern regions spreading out behind him. He was used to seeing the limitless northern vista, the sharp lines of the horizons dropping off to north-west and north-east. But men quickly adjusted to this, and the quiet fears of the Bridge-Builders grew more pronounced as days passed.

 

They were engineering fears. The strength of the pontoons. The amount of wood available. The security of the stays On the bank. The still-unresolved question of where future pontoons would lead.

 

Every day, Future Constant would ride out to the construction-site, ostensibly to inspect the progress of the work, but in reality to stare northwards with his Surveyor’s eyeglasses, seeking the still-elusive opposite bank.

 

Future Mann’s own doubts were reinforced when suddenly he and the other Surveyors working on the pontoon were recalled to the city.

 

It had been decided, as a contingency-plan, that an alternative route to the west or east would be sought. The work on the pontoons was to continue, but if a narrower part of the river could be found then the city would steer towards it.

 

Future then realised that the Council of Navigators was aware of the hazardous nature of the pontoon-bridge. Only once or twice in all the history of Earth had the city deviated to one side or another.

 

Destaine’s Directive was explicit: the city must move north, due north. Any movement to one side or another must be compensated for by a return to the original path, and overall northerly velocity must be maintained.

 

In theory, this presented no difficulty, but in practice any deviation from true north in excess of twelve degrees put strain on the nuclear winches. A few hundred miles before, the city had deviated to avoid a mountainous region, and had moved for more than eighty miles at an angular deviation of thirty degrees, and another hundred miles at twenty degrees to return them to their original line. The damage then caused to the bearings of the traction-equipment by the necessary increase in speed was still not fully repaired.

 

Future Mann was instructed to explore many miles to the west of the city, and other Surveyors took other routes, some to the west and some to the east. Mann knew that the regions he covered were sometimes thirty or forty degrees away from true north, and that even if he did find a safe route the nuclear winches might break down entirely under the strain.

 

In any event, his reports were the same as those of all the other Surveyors. However far to either side they explored, they came eventually to the river that lay in their path. It would have to be crossed, and there was nowhere that presented even a hint of an opposite bank.

 

* * * *

 

Towards the end of the 20th Century, an Australian particle physicist named Francis Destaine developed a process which he called transliteration. When some of its effects were first publicised, the popular press latched on to it as an anti-gravity device, though in fact this was a distortion of the true state of affairs.

 

Treating gravitation conceptually as a field phenomenon analogous to that of electromagnetic radiation, with a ‘graviton’ as the supposed elementary particle, Destaine devised a field-generator which created a region of space in which normal rules of gravitation did not apply. He discovered, for instance, that gravity could be cosmically repulsive—as opposed to attractive—and it was this that earned the label of anti-gravity. In fact, the energy consumed by his field-generator was so great that there could be no practical application for what he had discovered.

 

It was during this period that the need for natural energy-resources became critical. Though fusion reactors were theoretically possible, no one had yet discovered a way of containing the prodigious amounts of released energy. Fossil fuels were being used up rapidly, and there seemed to be no long-term solution to the world-wide energy shortage.

 

It was in this climate that Destaine was working. As his generator consumed vast amounts of energy with no apparent yield, he was unable to obtain official backing. Even when he claimed to have discovered a natural transliteration ‘window’ on Earth, where its effects could be harnessed by his generator to produce what he said would be unlimited amounts of electrical energy, he was unable to raise the necessary funds.

 

Finally, by methods unknown, Destaine raised the money privately.

 

Obtaining permission from the Russian government, he and a large staff of researchers and technicians assembled a mobile transliteration generator in the Yakutskaya province of Northern Siberia. It was here, said Destaine, that the natural transliteration window existed.

 

In spite of amused contempt from other scientists, Destaine persevered with his work. Meanwhile, in lieu of large quantities of electricity emanating from Northern Siberia, normal research into conventional energy-production continued.

 

Approximately six months after Destaine moved to Yakutskaya, his backers announced that he, his staff and his mobile station had suddenly ceased reporting. A search of the area was conducted, but without results. A few weeks later it was established that, inexplicably, all trace of Destaine and the others had vanished.

 

There was much evidence of activity in the area ... particularly in the form of tracks in the snow and discarded pieces of equipment ... but of the mobile station, which weighed over sixty tons, of the eighty-three people aboard it and of Destaine and his now famous graviton field-generator there was not a single sign.

 

In time, the mystery was forgotten, though every now and then the media would rehearse some of the more fascinating aspects of the disappearance.

 

Destaine’s work, though, had an unexpected legacy. The original backers, seeking to recoup some of their original investment, hired more researchers and alternative uses for the transliteral generator were sought. Finally, an adapted form of the field was found to be powerful enough to be used as a barrier in nuclear reactors, and fusion power became a reality.

 

Transliteral physics became a reality, too. More natural transliteration windows were discovered—though Destaine’s original one in Russia was never located—and in much the way that he had speculated, large quantities of electrical power could be derived by tapping these gravitational fault-zones with a graviton generator.

 

There was a minor difficulty: the transliteration windows moved.

 

To tap the energy, the graviton generator had to be moved at exactly the same speed as the transliteration window: speeds varied marginally, but were usually in the region of one-hundredth of a mile an hour.

 

Then, almost one hundred and twenty-seven years after Destaine’s disappearance, a new transliteration window was discovered in Northern Spain. A Destaine generator was assembled, and preparations were made to commence tapping the power. But scientific curiosity was being aroused by these transliteration windows: what was on the other side?

 

A firm in Geneva designed a portable transliteration generator that would allow a man to pass through. A volunteer was found ... and he passed through.

 

He found himself in terrain almost exactly like that which he had just left. But the horizons were wrong. The ground appeared to be concave. In one direction the ground curved up towards a distant point ... in the other it flattened out into a vast and apparently limitless plain.

 

And hauling itself across that plain, on a crude arrangement of tracks and cables, was Destaine’s original station.

 

* * * *

 

‘That’s the mobile generator Destaine built,’ said Langham, pointing at the screen.

 

Gerdun Mann, now physically refreshed but suffering under some mental strain, stared at the station.

 

‘You said it had disappeared in Russia,’ he said.

 

‘That’s right. But that was a hundred and twenty-seven years ago. This transliteration window was discovered only recently, and is presumably the same one Destaine found. I told you, the windows move.’

 

‘And the movement roughly correlates with the movement of the ground through there.’

 

‘No, it correlates exactly. Since it disappeared, Destaine’s station has covered about eleven and a half thousand miles. For more than a hundred years it has been crossing a transliteral analogue of Asia and Europe. It is now, as we are, in Portugal.’

 

Langham instructed the camera-operator to pan ahead of the station. There, now appreciably nearer, was the expanse of water.

 

‘So far Destaine’s station has always been on land. The sea is not in their experience. The people in the station have started to build a bridge ... across the Atlantic Ocean!’

 

* * * *

 

Four

 

As a Surveyor, Future Mann was intrinsically out of sympathy with the Terminator movement. He had been trained to see the ground that lay before the city as its future environment. The ground that lay behind was in the past, its usefulness fulfilled and spent. It was from the future that came the trees and crops that fed and sustained the people of Earth, the herds of wild animals that provided meat and a means of local transport.

 

In the past lay danger; Destaine’s Directive could not be clearer.

 

It would be a temptation to stand in the way of our northwards progress, he wrote. But such a temptation must be resisted absolutely. Danger and almost certain death lie to the south of us. No man nor any of his artefacts could withstand the gravitational stresses and centrifugal forces that obtain in the south. We must maintain position ... somewhere to the north lies our window to safety.

 

So it was written into the very constitution of the city that the north was synonymous with safety. How then, thought Future Mann, would Destaine have confronted such a river as this ? Could this be the window of which he had written ?

 

He stood now in the crowded central square of the city, watching the Terminators’ public meeting.

 

It was the first time in the history of the city that they had come out into the open, for by their very principles they stood for an ideal that directly contradicted Destaine’s words. There had always been Terminator thought in the city, once, it was rumoured, in the person of a president Navigator. But always in the past the Terminator movement had stayed out of sight, and out of general credibility.

 

So many people in the city had now seen the river for themselves, or had heard first-hand reports of it, that there was no longer any doubt that this was indeed the greatest single natural obstacle the city had ever had to face. The Terminators at last had a good case, and they no longer saw the need to hide that case from the people.

 

‘—stop the city, destroy our winches. This is fertile soil, we need not cross any river to find better-’

 

It was in the Directive: the winches must always turn. Again: however fertile the soil of one region, there will always be more to come.

 

Navigator Jase stood silently to one side of the platform. He was not scheduled to speak, though many of those who did invoked his name.

 

‘—the city will founder on any bridge across that river. Our Bridge-Builders are skilled, but before they have always had an opposite bank on which to lay foundations-’

 

Bridges must be built to cross water. Paths must be diverted to avoid high mountains or deep chasms.

 

‘—our Surveyors have proved that we cannot avoid the river. We must stop, or we must cross that river. There is no hope of our crossing that water safely-’

 

At all times, we must be fully prepared for what is to come. Men must go out to the north of the city, and survey for us a safe passage. Their word must be followed absolutely.

 

‘—the Navigators are navigating us to our destruction. Now is the time to terminate our journey before it is too late-’

 

I have created the Council of Navigators. In the Council I vest the safety of the city of Earth. The Council’s decisions must never be questioned.

 

The speaker stepped down, and another climbed up to the tiny platform. During this interval, Mann tried to count the size of the audience. There had been a census in the city recently which had revealed a population of just over eight hundred people; Mann estimated that at least half that number were in the square.

 

The new speaker was one unknown to Future Mann. He claimed to have a scientific training, and could present scientific arguments for the case of the Terminators.

 

Future Mann did not give him all his concentration; he had heard many of these quasi-scientific notions before in private. But one sentence caught his attention: a question he had never heard asked before.

 

‘—the Navigators say that we must continue northwards, for no living thing could survive to the south. I ask you this. We are all familiar with the herds of wild animals that we often encounter, with the natural fruits and vegetables that we find. These are living beings ... they require a stable climate and a natural environment in which to grow. They come down from the north, we take what we want, and allow the rest to pass on to the south. Do they go to a region where nothing can survive?’

 

Future Mann frowned. There was silence in the tightly-packed square.

 

* * * *

 

There was a long period of inactivity inside the transporter. In answer to Gerdun Mann’s question—’Why me?’ —Langham had been evasive for the first time.

 

‘I can’t tell you,’ he said. ‘But I think I may be able to show you.’

 

For a long period, the camera had rested on the scene of activity around the building of the bridge. A storm had blown up during the night, and in spite of the best efforts of the men there, considerable damage had been inflicted. Now, in the morning, the wind had dropped but the sea was still high. With considerable bravery, work on the bridge continued.

 

Occasionally, the operator panned the camera back towards the station and Langham watched the screen attentively, instructing the operator to zoom in to a close-up on selected men. After two hours of this, Langham beckoned to Mann.

 

‘This is the one. Look at him.’

 

Gerdun Mann stared. Framed unsteadily in the screen— the camera-lens had zoomed in to its maximum focal length—was a man riding a horse. He rode alone towards the bridge-site, his head bent down thoughtfully.

 

‘Recognise him?’

 

Gerdun shook his head...not in denial, but in surprise.

 

‘He looks like me.’

 

‘That’s why you were chosen. You were located by a matching of your appearance on the central photo-ident file.’

 

‘I don’t understand.’

 

Langham signalled to the cameraman to keep the horseman in view.

 

‘We’ve got less than fifteen days before the transliteration window reaches the coast. Before that happens, we’ve got to divert the station towards the window and get it through. If we don’t, the people in the station—and they number several hundred—will try to float across the Atlantic on a home-made bridge. You’ve already seen what one inshore storm will do to the bridge.

 

‘If they decide not to cross the water, they will be obliged to stop. The transliteration window will not stop, and it will pass on over the sea. Once that happens, we have no hope at all of rescuing them.’

 

‘But I don’t see what I can do on my own.’

 

Langham gestured towards the image of Mann’s double. ‘We want you to impersonate that man, infiltrate the station. Inside it there is Destaine’s original graviton field-generator. All you have to do is switch it on ... we can do the rest from here.’ 

 

‘And supposing I can’t find it?’

 

‘You will. We have plans of the original construction.’

 

‘If it’s so simple, why do we have to go to the lengths of impersonating one of the men?’

 

‘Because it isn’t that simple. We’ve had great difficulty in communicating with the people. We can pass to and fro through the window, but to do so we have to wear portable transliteration gear. This is bulky and very heavy, and we presume that the appearance of the men who wear it frightens the people. We’ve made several attempts to approach them, but we succeed only in provoking a violent attack.’

 

Mann said: ‘These suits have to be worn all the time?’

 

‘No. But as I said, they’re bulky and it takes time and several assistants to put them on or take them off.’

 

‘And you’ve never succeeded in communicating with, the people?’

 

Langham shook his head.

 

‘The last few attempts have been made by the army. We issued them with hypodermic guns, hoping to stun the defenders ... but they’ve fought back in earnest. General Dula has lost several men, and we’ve had to suspend that kind of operation indefinitely.’

 

‘What does force ever achieve?’

 

‘In this case we hoped, in lieu of being able to communicate with them directly, that we could forcibly alter the course of the station and bring it nearer the window. Then we could bring the people through one by one. But as I say, this has had to be abandoned now. Our only hope is to activate the generator that transliterated the whole station originally and bring everyone through in one move.’

 

‘So you want me to go in alone, and do this myself.’

 

‘That’s right.’ Langham looked again at the screen. Mann’s double rode on northwards, alone. ‘We can’t order you to do this ... all we can do is request it.’

 

‘And if I don’t?’

 

‘We send in Dula’s men again.’

 

‘Would that work?’

 

‘I doubt it.’

 

* * * *

 

Future Mann stayed five days at the construction site, encouraged in some ways at the renewed progress of the pontoons, but alarmed by reports from new arrivals from the city. On Mann’s last day at the site. Future Colne arrived from the city and spoke privately to him.

 

The Terminators had made a formal representation to the Council, requesting that the city be stopped and the planned crossing abandoned. After due consideration, the Council had decided to continue with the bridge. Navigator Jase had promptly resigned, committed himself overtly to the Terminator cause and was now their leading spokesman.

 

There had been a confrontation between some of the Terminators and a group of Militiamen, and a riot had developed. In the chaos, some of the Terminators had managed to sever one of the cables.

 

The city had been stopped, but only temporarily, and only long enough for the transfer to direct drive to be effected. The city was now independent of the tracks and cables, and needed only a comparatively rough-laid path on which to travel.

 

As a result of this the Cable and Track Guildsmen were freed from their normal tasks and were coming to reinforce the work on the bridge. Most of the Militiamen, too, were being relieved of their work. The Council considered this an acceptable risk, in view of the recent lack of raider activity.

 

‘So it’s a total concentration on the bridge from now on ?’ said Mann.

 

‘Looks like it.’

 

They both stared at the pontoon bridge, stretching for two or three hundred yards into the water.

 

Later in the day. Future Mann started his return to the city. He rode alone as he always did, with some misgivings about what he would find in the city. There had never been riots on Earth before, and he was wondering what damage he would find.

 

In the five days he had been away the city had covered more than a mile in time and was now only a short riding distance from the bank of the river. He knew that the Navigators in their raised cockpit could see the bridge, and would be heading directly for it.

 

Lost in thought, worried about what he would find in the city, frightened of what the future held for him and for everyone. Future Mann did not notice the five men until they had surrounded him. One of them grabbed his horse’s bridle, and forced him to stop.

 

‘What’s the matter?’ Mann said, jumping to the immediate conclusion that they were Terminators. He recognised none of them.

 

The men made no reply, and instead led his horse to one side, away from the city. Future Mann repeated his question, but there was still no response. Mann looked in the direction in which he was being led, wondering why he should be moved away from the city.

 

Then his gaze fell on a large, dark figure ... and he recognised it at once. A raider!

 

He pulled hard on the horse’s rein, trying to pull her head round, and dug his heels into her sides. She reared up, hooves flailing.

 

‘Catch him!’ someone shouted, and one of the men managed to seize hold of Mann’s leg. He tried to kick free, but an instant later something hard and sharp was driven into his shin. The man hung on, and two of the others reached for the bridle.

 

Future Mann found that his resistance was weakening. Slowly, the horse was brought under control ... and he slumped in his saddle. He fell sideways, and was caught by two of the men.

 

Fully conscious, but unable to move, Future Mann was carried towards the raider. Behind him, his horse was being led.

 

What followed was for Mann partly incomprehensible and partly nightmarish. The raider stood waiting, and there appeared to be a dead or unconscious raider lying on the ground nearby. This dead raider was lifted up, and fitted around his shoulders. Mann could not resist, could not struggle, but a great and uncontrollable fear swelled in him.

 

When the dead raider was fitted about him, he was lifted and carried once more. This time, it was for a shorter distance.

 

And then, totally inexplicably, he found himself in a metal room where several men stood waiting.

 

* * * *

 

Five

 

Gerdun Mann walked through the transliteration window, and nearly fell. He had been warned that the ground would appear to change instantaneously from being level to a forty-five degree angle; but he was still unprepared for it when it came. He recovered immediately, discovering that once one was through the window the ground felt as if it were level.

 

A technician was waiting for him on the other side. Two more technicians followed him through the window, and the three of them helped Mann take off his transliteration equipment, a hitherto unacceptable risk. A horse was tethered nearby.

 

Wearing the clothes that had been taken from Future Mann, he went to the horse. He had never ridden a horse, and there hadn’t been time to learn, so he was obliged to lead it.

 

He stood still for a moment, patting the horse’s neck and regarding his surroundings. Once again he had been prepared for what he was to see by what the television camera had shown him; but that was no substitute for actually being here.

 

To his left was the sea. He could see the shore less than a mile away, and beyond that the surface of the sea rose up northwards until it vanished in the haze. He could just hear the sound of the surf, smell the salt on the breeze that blew from the coast.

 

Ahead of him, and slightly to his right, was the station. Behind it, he could see the track that had been abandoned, and the last of the cable-stay emplacements.

 

And behind that... the ground rose up once more. It was a dizzying, vertiginous feeling, looking at the ground as if viewed from an impossibly high cliff.

 

He looked away, remembering Langham’s warning that some of his men had been made physically nauseated by the sight, their senses unable to comprehend the limitless nature of the surface of this world.

 

He paused a while longer, trying to get his bearings.

 

One difficulty for him was that north on this world was not the same as north on his. To the people of the station, their way led up the side of the planet, towards the infinitely distant north pole. But the analogous direction on Earth was one hundred and ten degrees away from this, almost south-west. Langham had been unable to account for this; logically, north on this planet should be north on Earth ... but that was not the way.

 

He glanced up at the sun, catching a glimpse of its cross-shape before the brilliance forced him to look away. He rubbed his eyes, looked over towards the station and began leading the horse in that direction.

 

He had no idea what to expect. He was the first man from true Earth to go into Destaine’s station since it vanished. No one on Earth was even sure about what common language was employed, even though their captive had shown that he spoke a recognizable English. He had Langham’s plan of Destaine’s station as it was first built; but even the most superficial glance at it confirmed that it had been much changed and expanded since then.

 

Mann was confident, though, that he would be able to find the graviton field-generator. It was situated in the reactor-room, in the base of the station, and it was so large a piece of equipment that it was unlikely that it would have been moved.

 

He walked right up to the edge of the station, passing several men on the way. One or two nodded to him, and he returned the greeting in kind. He kept his movements purposeful so that he wouldn’t be detained in conversation.

 

He found himself at the side of the station.

 

The main base was some twenty feet above the ground, and beneath it he could see some of the drive machinery. The mechanism was crude. As far as he could see, an arrangement of wheels was geared up to three large winches placed deep in the centre. The wheels looked ill-suited to the work they were doing, and Mann recalled Langham telling him that once the station had been fitted with caterpillar tracks. These wheels as such were probably once the runners for those tracks.

 

From where he was standing, he could see no entry into the station. He walked the horse round to the station front, remembering that most of the movements to and from the station had been seen here.

 

Directly at the front of the station, beneath the main base, there was a wide tunnel. He led the horse in, expecting her to rear ... but she was evidently accustomed to the tunnel and walked quietly behind him.

 

To each side of him, Gerdun Mann now saw several doorways with staircases behind them, evidently leading up to the interior of the station. He walked for a short distance, wondering which one he should take.

 

Suddenly a voice called out: ‘I’ll take the horse, sir.’

 

Mann turned round. A young boy was standing a few feet away from him.

 

‘You needn’t bother with her. Future. I’ll take her in.’

 

‘Er—thanks.’ Mann walked the horse over to the boy and handed him the rein.

 

‘Are you going up into the city, sir?’

 

‘Yes.’

 

‘Be careful. Future Mann. There’s a lot of trouble up there.’

 

‘Trouble?’

 

‘Fighting, and some shooting. I heard about an hour ago that they were trying to set fire to the city.’

 

‘Is it serious?’

 

‘Well, I hear the fires are out. But there’s still a lot of fighting. Of course, you’ve been north a few days, you haven’t seen the worst.’ The boy looked closely at Mann. ‘Don’t worry about your family, sir. Most of the women and children have been evacuated until the trouble’s dealt with. They’ll be back in the main part of the city by the time we reach the bridge.’

 

‘Where are they now ?’

 

‘They’re in the hospital, sir. They’re quite safe.’

 

‘Good. I’ll go and see them.’

 

Gerdun Mann nodded to the boy, and headed for the nearest staircase. He walked up the flight of stairs and emerged in a narrow passageway, bounded on each side by what looked like wooden buildings. Several people pushed past him, and in the near distance he heard the sound of shouting.

 

He walked down the passageway, and came to a slightly wider one.

 

Here there were many more people, mostly men. Several of them carried crossbows, and one or two held placards or clubs.

 

No one took any notice of him, their attention diverted towards a tightly-packed group of men at the far end of the passage. They were all shouting and waving their fists.

 

‘What’s going on?’ Mann said to one of the crossbow-carriers near him.

 

The man looked at him. ‘You’re Future Mann.’

 

‘Yes.’

 

‘It’s the Terminators, sir. Trying to reach the reactor. They want to stop the city.’

 

Gerdun Mann made to say something else, but suddenly an order was given and all the crossbowmen moved towards the crowd. Mann looked in the opposite direction, saw there were fewer people there. He headed that way.

 

He found a doorway and stepped into its shelter. From a pocket of the leather tunic Langham’s men had taken from the captive, Mann took the plan. He consulted it anxiously, trying to locate where he was so that he could reach the reactor-room.

 

Behind him there was a renewed outburst of shouting and he heard many people running in his direction. Mann pushed his way through the door, and found two children lying on the floor, their arms around one another.

 

He closed the door. One of the children burst into tears.

 

‘Where’s the reactor-room?’ Mann said to the other child. ‘Do you know where it is ?’

 

The boy shook his head.

 

‘Come on ... it’s important!’ There was still no response. ‘Listen, do you know who I am ? I’m a Future. You’ve got to tell me.’ By now, Mann had realised that a ‘Future’ held a position of some importance in the station.

 

‘Then you know where it is.’

 

‘Tell me. Pretend I don’t.’

 

The boy shook his head again, and Mann seized his shoulder. ‘Is it by the winches?’

 

‘It’s under the cockpit,’ said the girl through her tears. ‘Why don’t you know where it is?’

 

Mann went back through the doorway, and consulted his plan again. The cockpit was clearly marked as ‘Control Cabin’—or at least he presumed the two were synonymous —and was situated at the front of the station. In the passageway he tried to get his bearings. He looked up, trying to catch a glimpse of the position of the sun. Instead, apparently rearing up over the city, was the countryside to the south.

 

It took Mann a second or two to recover from the unexpectedness of this discovery, and realise that logically the control cabin would lie at the opposite end of the station.

 

He walked that way, avoiding large groups of people and changing direction if he saw any signs of trouble.

 

He came in the end to a large wooden building that was separate from the others. There was one large entrance which was heavily guarded by a cordon of crossbowmen. Mann thought for a moment, then moved around to one side. In a narrow passage he saw two or three smaller entrances ... but almost as soon as he had turned the comer three crossbowmen came and confronted him.

 

‘Where are you going?’

 

‘To the ... cockpit,’ said Mann.

 

‘Who are you?’

 

‘Don’t you recognise me?’

 

One of the crossbowmen said something quietly to the others.

 

‘Sorry, Future Mann. There’s an emergency on.’

 

The crossbowmen stood back, and Mann walked on.

 

He made for the first doorway, and went inside. There was a flight of steps, and he went up them. At the top there was a corridor, well lit by electricity. He walked down it, looking into rooms which had doors open. There appeared to be no one about. At the end of the corridor, another staircase.

 

He walked up this, along another passage and came out into a small room crammed with instruments and controls. There were five men here, sitting or standing by the instruments. One man stood in front of a window, staring forward. In his first few seconds in the room, Mann caught a glimpse of the view: it was directly ahead of the station, and the sea was now clearly visible.

 

The man by the window turned.

 

‘Future Mann! You have a new survey-report?’

 

Mann was temporarily lost for words. Langham’s interrogation of the captive had revealed that the man was a ‘surveyor’, but the actual nature of his work had never been clearly understood.

 

‘I’ve come from the bridge,’ he said in a moment. ‘It won’t be ready in time.’

 

‘There are still a few more days.’

 

‘Even so...I have an alternative plan.’

 

The man at the window walked towards him. ‘If you have no report, Future-Surveyor, you have no right of access to the cockpit.’

 

Abruptly, an alarm-bell rang out. A few yards away there was a loud bang, and a shout. There came the sound of running feet.

 

The man turned away and went to a console. ‘Get back to your station, Future-Surveyor. We are too busy to be interrupted.’

 

Mann looked round. At the far side of the control-cabin there was another doorway, marked with a radioactivity-warning sign. Disregarding the other men, he walked towards it. At that moment, the door through which he had entered opened again and suddenly several men poured into the room. They were holding crossbows and clubs.

 

‘You’re all under arrest!’ the leading man shouted. He aimed his crossbow at the Navigator who had spoken to Mann, and stepped forward. ‘The city has to be stopped. You are taking us to our deaths.’

 

At the intrusion, Mann had stopped by the door. One of the men was aiming a crossbow at him.

 

‘As duty-Navigator, I order you to leave the cockpit.’

 

‘You no longer have authority. Olssen has surrendered.’

 

Gerdun Mann had no wish to be caught up in a local revolution. He moved quickly, opening the door and almost throwing himself through. As he did so, one of the men loosed his crossbow. The bolt narrowly missed him, hit the door and clattered down on to some metal steps. Without pausing, Mann hurried down the steps.

 

He found himself in the reactor-room. He paid no attention to the reactor itself, but headed for the graviton field-generator which, according to Langham’s plan, was situated at the rear of the room.

 

At first, he was unable to find it ... then saw a large machine covered with a sheet. He heard the sound of feet on the steps at the far side of the reactor-room.

 

He tore the sheet aside. He knew exactly what he had to do. Langham had shown him a simulator on true Earth, and Mann had practised many times.

 

Two men came down the steps and stood at the bottom, looking for him in the poorly-lit room. Mann ducked low, and turned the first of the five switches that activated the generator.

 

‘You’re under arrest, Future!’ They had seen him now and were advancing on him, crossbows raised.

 

‘Keep away! This is important.’

 

‘Nothing is as important as stopping the city.’

 

Four of the five switches were open now, and the fifth one was stiff. The old generator, which hadn’t been used for more than a hundred years, was coming to life. Dials moved, warning-lights came on, a cathode-ray scanner glowed vivid green.

 

‘Stop ... or we shoot!’

 

The fifth switch suddenly freed, and there was a loud noise. It began as a low roar, then quickly raised in pitch. Around them, the lights of the reactor-room began to dim. Almost the whole output of the station’s reactor was being used up by the generator ... taking power away from the winches, halting the long journey of Earth city.

 

The crossbows were raised, both aimed at him.

 

Then one of the men lowered his weapon.

 

‘Future ... what have you done?’

 

Mann turned to face them, put up his hands defensively.

 

‘Don’t shoot,’ he said weakly.

 

The other man lowered his weapon too.

 

The noise from the generator continued to mount; now it was a high whine.

 

‘The winches have stopped,’ he said. The Future has stopped the city.’

 

They ignored Mann, and went back to the steps leading to the control cabin. Mann turned back to the field-generator, it was now 90% operational, and still mounting. As the needle of the dial touched 100%, he picked up the sheet, and threw it once more over the machine.

 

* * * *

 

Gerdun Mann walked out from under the base of the station and looked around.

 

Immediately in front of him, less than a mile away, was the sea. Beyond that, a very clear horizon. There were two ships in view.

 

He looked over to one side. A few hundred yards away he could see Langham’s transporter, and beyond it a cluster of helicopters, ambulances and trucks. He walked towards them.

 

After he had covered half the distance, he turned and looked back at the station.

 

The people of the city of Earth were looking at the planet of Earth. As Mann had walked through the station, the Terminators were announcing that the city had stopped ... and now the people came to the side of the station, looking at a world where there were horizons on all sides. A world where the ground didn’t move. Where the sun was a simple sphere.

 

Mann sat down on the dry soil. He felt strangely reactionless.

 

A few minutes later, a vehicle stopped nearby and Langham stepped out. He shook Mann’s hand, congratulated him.

 

Mann just smiled. He didn’t feel as if he had saved a world. He was thinking of all that had to be done. There were still people in that hyperboloid world: the people who had been away from the city when the generator was activated. They would have to be collected. All the people of the station would have to be rehabilitated.

 

Then there was the curious fact of the captive. The man who shared his name, who looked so remarkably like him. He wondered how much more than this they had in common; perhaps one of his own ancestors had been a member of Destaine’s original crew.

 

And Gerdun Mann thought of the pile of books that lay unread in his hotel room. He hadn’t forgotten those, but he was beginning to realize that it might be some time before he got around to looking at them.