"What?"

"The Raft is half a mile wide. This Bridge is merely a hundred yards long."

Hollerbach frowned; then the implications began to hit him.

"Find Rees," Decker snapped. "I'll meet you both in your office in a quarter of an hour." With a curt nod, he turned and walked away.

Rees found the atmosphere in Hollerbach's office electric.

"Close the door," Decker growled.

Rees sat before Hollerbach's desk. Hollerbach sat opposite, long fingers pulling at the papery skin of his hands. Decker sucked breath through his wide nostrils; eyes downcast, he paced around the small office.

Rees frowned. "Why the funereal atmosphere? What's happened?"

Hollerbach leaned forward. "We have a... complication." He sketched out Gord's reservations. "We have to check his figures, of course. But-"

"But he's right," Rees said. "You know he is, don't you?"

Hollerbach sighed, the air sc.r.a.ping over his throat. "Of course he's right. And if the rest of us hadn't got carried away with glamorous speculations about gravitational slingshots and a mile-wide dome, we'd have asked the same questions. And come to the same conclusions."

Rees nodded. "But if we use the Bridge we're facing problems we didn't antic.i.p.ate. We thought we could save everybody." His eyes flicked to Decker. "Now we have to choose."

Decker's face was dark with anger. "And so you turn to me."

Rees rubbed the s.p.a.ce between his eyes. "Decker, provided we manage the departure cleanly those left behind will survive for hundreds, thousands of shifts-"

"I hope those abandoned by your shining ship will take it so philosophically." Decker spat. "Scientists. Answer me this. Will this adventure work? Could the pa.s.sengers of the Bridge actually survive a pa.s.sage around the Core, and then through s.p.a.ce to the new nebula? We're looking at a very different set-up from Rees's original idea."

Rees nodded slowly. "We'll need supply machines, whatever compressed air we can carry in the confines of the Bridge, perhaps plants to convert stale air to-"

"Spare me the trivia," Decker snapped. "This absurd project will entail backbreaking labor, injury, death. And no doubt the departing Bridge will siphon off many of mankind's best brains, worsening the lot of those left behind still further.

"If this mission does not have a reasonable chance of success then I won't back it. It's as simple as that. I won't shorten the lives of the bulk of those I'm responsible for, solely to give a few heroes a pleasure ride."

"You know," Hollerbach said thoughtfully, "I doubt that when you - ah, acquired - power on this Raft you imagined having to face decisions like this."

Decker scowled. "Are you mocking me, Scientist?"

Hollerbach closed his eyes. "No."

"Let's think it through," Rees said. "Hollerbach, we need to transport a genetic pool large enough to sustain the race. How many people?"

Hollerbach shrugged. "Four or five hundred?"

"Can we accommodate so many?"

Hollerbach paused before answering. "Yes," he said slowly. "But it will take careful management. Strict planning, rationing... It will be no pleasure ride."

Decker growled, "Genetic pool? Your five hundred will arrive like babies in the new world, without resources. Before they breed they will have to find a way of not falling into the Core of the new nebula."

Rees nodded. "Yes. But so did the Crew of the original Ship. Our migrants will be worse off materially... but at least they will know what to expect."

Decker drove his fist into his thigh. "So you're telling me that the mission can succeed, that a new colony could survive? Hollerbach, you agree?"

"Yes," Hollerbach said quietly. "We have to work out the details. But - yes. You have my a.s.surance."

Decker closed his eyes and his great shoulders slumped. "All right. We must continue with your scheme. And this time, try to foresee the problems."

Rees felt a vast relief. If Decker had decided otherwise - if the great goal had been taken away - how would he, Rees, have whiled away the rest of his life?

He shuddered. It was unimaginable.

"Now we face further actions," Hollerbach said. He held up his skeletal hand and counted points on his fingers. "Obviously we must continue our studies on the mission itself - the equipage, separation, guidance of the Bridge. For those left behind, we have to think about moving the Raft."

Decker looked surprised.

"Decker, that star up there isn't going to go away. We'd have shifted out from under it long ago, in normal times. Now that the Raft is fated to stay in this Nebula, we must move it. And finally..." Hollerbach's voice tailed away.

"And finally," Decker said bitterly, "we have to think about how to select those who travel on the Bridge. And those who stay behind."

Rees said, "Perhaps some kind of ballot would be fair..."

Decker shook his head. "No. This jaunt will only succeed if you have the right people."

Hollerbach nodded. "You're right, of course."

Rees frowned. "...I guess so. But - who selects the 'right' crew?"

Decker glared at him, the scars on his face deepening into a mask of pain. "Who do you think?"

Rees cradled his drink globe. "So that's it," he told Pallis. "Now Decker faces the decision of his life."

Pallis stood before his cage of young trees, poked at the wooden bars. Some of the trees were almost old enough to release, he reflected absently. "Power brings responsibility, it seems. I'm not certain Decker understood that when he emerged on top from that joke Committee. But he sure understands it now... Decker will make the right decision; let's hope the rest of us do the same."

"What do you mean, the rest of us?"

Pallis lifted the cage from its stand; it was light, if bulky, and he held it out to Rees. The young Scientist put down his drink globe and took the cage uncertainly, staring at the agitated young trees. "This should go on the journey," Pallis said. "Maybe you should take more. Release them into the new nebula, let them breed - and, in a few hundred shifts, whole new forests will begin to form. If the new place doesn't have its own already..."

"Why are you giving this to me? I don't understand, tree-pilot."

"But I do," Sheen said.

Pallis whirled. Rees gasped, juggling the cage in his shock.

She stood just inside the doorway, diffuse starlight catching the fine hairs on her bare arms.

Pallis, with hot shame, felt himself blush; seeing her standing there, in his own cabin, made him feel like a clumsy adolescent. "I wasn't expecting you," he said lamely.

She laughed. "I can see that. Well, am I not to be invited in? Can't I have a drink?"

"Of course..."

Sheen settled comfortably to the floor, crossing her legs under her. She nodded to Rees.

Rees looked from Pallis to Sheen and back, his color deepening. Pallis was surprised. Did Rees have some feeling for his former supervisor... even after his treatment during his return exile on the Belt? Rees stood up, awkwardly fumbling with the cage. "I'll talk to you again, Pallis-"

"You don't have to go," Pallis said quickly.

Sheen's eyes sparkled with amus.e.m.e.nt.

Again Rees looked from one to the other. "I guess it would be for the best," he said. With mumbled farewells, he left.

Pallis handed Sheen a drink globe. "So he's carrying a torch for you."

"Adolescent l.u.s.t," she said starkly.

Pallis grinned. "I can understand that. But Rees is no adolescent."

"I know that. He's become determined, and he's driving us all ahead of him. He's the savior of the world. But he's also a b.l.o.o.d.y idiot when he wants to be."

"I think he's jealous..."

"Is there something for him to be jealous of, tree-pilot?"

Pallis dropped his eyes without reply.

"So," she said briskly, "you're not travelling on the Bridge. That was the meaning of your gift to Rees, wasn't it?"

He nodded, turning to the s.p.a.ce the cage had occupied.

"There's not much of my life left," he said slowly. "My place on that Bridge would be better to go to some youngster."

She reached forward and touched his knee; the feeling of her flesh was electric. "They'll only invite you to go if they think they need you."

He snorted. "Sheen, by the time those caged skitters have grown, my stiffening corpse will long since have been hurled over the Rim. And what use will I be without a tree to fly?" He pointed to the flying forest hidden by the cabin's roof. "My life is the forest up there. After the Bridge goes, the Raft will still be here, for a long time to come. And they're going to need their trees."

She nodded. "Well, I understand, even if I don't agree." She fixed him with her clear eyes. "I guess we can debate it after the Bridge has gone."

He gasped; then he reached out and took her hand. "What are you talking about? Surely you're not planning to stay too? Sheen, you're crazy-"

"Tree-pilot," she snapped, "I did not insult you on the quality of your decision." She let her hand rest in his. "As you said, the Raft is going to be here for a long time to come. And so is the Belt. It's going to be grim after the Bridge departs, taking away - all our hope. But someone will have to keep things turning. Someone will have to call the shift changes. And, like you, I find I don't want to leave behind my life."

He nodded. "Well, I won't say I agree-"

She said warningly, "Tree-pilot-"

"But I respect your decision. And-" He felt the heat rise to his face again. "And I'm glad you'll still be here."

She smiled and moved her face closer to his. "What are you trying to say, tree-pilot?"

"Maybe we can keep each other company."

She reached up, took a curl of his beard, and tugged it gently. "Yes. Maybe we can."

14.

ACAGE OF SCAFFOLDING obscured the Bridge's clean lines. Crew members crawled over the scaffolding fixing steam jets to the Bridge's hull. Rees, with Hollerbach and Grye, walked around the perimeter of the work area. Rees eyed the project with a critical eye. "We're too slow, d.a.m.n it."

Grye twisted his hands together. "Rees, I'm forced to say that your detailed understanding of this project is woefully lacking. Come-" He beckoned. "Let me show you how much progress we have made." He slapped a plump hand against the wooden cage surrounding the Bridge; it was a rectangular box securely fastened to the deck, and it supported three broad hoops which wrapped around the Bridge itself. "We can't take chances with this," Grye said. "The last stage in the launch process will be the cutting away of the Bridge from the deck. When that is done, all that will support the Bridge will be this scaffolding. A mistake made here could cause catastrophic-"

"I know, I know," Rees said, irritated. "But the fact is we're running out of time..."

They came to the Bridge's open port. Under the supervision of Jaen and another Scientist, two burly workmen were manhandling an instrument out of the Observatory. The instrument - a ma.s.s spectrometer, Rees recognized - was dented and scratched, and its power lead terminated in a melted stump. The spectrometer was placed with several others in an eerie group some yards from the Bridge; the discarded instruments turned blinded sensors to the sky.

Hollerbach shuddered. "And this is something I certainly hesitate over," he said, his voice strained. "We face an awful dilemma. Every instrument we vandalize and throw out gives us floor s.p.a.ce and air for another four or five people. But can we afford to leave behind this telescope, that spectrometer? Is this device a mere luxury - or, in the unknown environs of our destination, will we leave ourselves blind in some key spectrum?"

Rees suppressed a sigh. Hesitation, delays, obfuscations, more delays... Obviously the Scientists could not metamorphose into men of action in mere hours - and he sympathized with the dilemmas they were trying to resolve - but he wished they could learn to establish and stick to priorities.

Now they came to a group of Scientists probing cautiously at a food machine. The huge device loomed over them, its outlets like stilled mouths. Rees knew that the machine was too large to carry into the Bridge's interior, and so it - and a second companion machine - would, rather absurdly, have to be lodged close to the port in the Bridge's outer corridor.

Grye and Hollerbach both made to speak, but Rees held up his hands. "No," he said acidly. "Let me go into the reasons why we can't possibly rush this particular process. We've calculated that if strict rationing is imposed during the flight two machines should satisfy our needs. This one even has an air filtration and oxygenation unit built into it, we've discovered..."

"Yes," Grye said eagerly, "but that calculation depends on a key a.s.sumption: that the machines will work at full efficiency inside the Bridge. And we don't know enough about their power supply to be sure. We know this machine's power source is built into it somehow - unlike the Bridge instruments, which shared a single unit by way of cables - and we even suspect, from the old manuals, that it's based on a microscopic black hole - but we're not sure. What if it requires starlight as a source of replenishment? What if it produces volumes of some noxious gas which, in the confines of the Bridge, will suffocate us all?"

Rees said, "We have to test and be sure, I accept that. If the efficiency of the machine goes down by just ten per cent - then that's fifty more people we have to leave behind."

Grye nodded. "Then you see-"

"I see that these decisions take time. But time is what we just don't have, d.a.m.n it..." Pressure built inside him: a pressure which, he knew, would not be relieved until, for better or worse, the Bridge was launched.

Walking on, they met Gord. The mine engineer and Nead, who was working as his a.s.sistant, were carrying a steam jet unit to the Bridge. Gord nodded briskly. "Gentlemen."

Rees studied the little mine engineer, his worries momentarily lifting. Gord had returned to his old efficient, bustling, slightly p.r.i.c.kly self; he was barely recognizable as the shadow Rees had found on the Boneys' worldlet. "You're doing well, Gord."

Gord scratched his bald pate. "We're progessing," he said lightly. "I'll say no more than that; but, yes, we're progressing."

Hollerbach leaned forward, hands folded behind his back. "What about this control system problem?"

Gord nodded cautiously. "Rees, are you up to date on this one? To direct the Bridge's fall - to change its...o...b..t - we need some way to control the steam jets we'll have fixed to the hull; but we don't want to make any breaches in the hull through which to pa.s.s our control lines. We don't even know if we can make breaches, come to that.

"Now it looks as if we can use components from the cannibalized Moles. Some of their motor units operate on an action-at-a-distance principle. I'm just a simple engineer; maybe you Scientists understand the ins and outs of it. But what it boils down to is that we may be able to operate the jets from inside the Bridge with a series of switches which won't need any physical connection to the jets at all. We're about to run tests on the extent to which the hull material blocks the signals."