Hollerbach lifted his head from the lab report, eyes smarting. He removed his spectacles, set them on the desk top before him, and began methodically to massage the ridge of bone' between his eyes. "Oh, do sit down, Mith," he said wearily.

Captain Mith continued to pace around the office. His face was a well of anger under its covering of black beard and his massive belly wobbled before him. Hollerbach noted that Mith's coverall was frayed at the hem, and even the golden Officer's threads at his collar looked dulled. "Sit down? How the hell can I sit down? I suppose you know I've got a Raft to run."

Hollerbach groaned inwardly, "Of course, but—"

Mith took an orrery from a crowded shelf and shook it at Hollerbach. "And while you Scientists swan around in here my people are sick and dying—"

"Oh, by the Bones, Mith, spare me the sanctimony!" Hollerbach thrust out his jaw. "Your father was just the same. All lectures and no damn use."

Mith's mouth was round. "Now, look, Hollerbach—"

"Lab tests take time. The equipment we're working with is hundreds of thousands of shifts old,

remember. We're doing our best, and all the bluster in the Nebula isn't going to speed us up. And you can put down that orrery, if you don't mind."

Mith looked at the dusty instrument. "Why the hell should I, you old fart?"

"Because it's the only one in the universe. And nobody knows how to fix it. Old fart yourself."

Mith growled — then barked laughter. "All right, all right." He set the orrery back on its shelf and pulled a hard-backed chair opposite the desk. He sat with legs splayed under his belly and raised troubled eyes to Hollerbach. "Look, Scientist, we shouldn't be scrapping. You have to understand how worried I am, how frightened the crew are."

Hollerbach spread his hands on the desk top; liver-spots stared back at him. "Of course I do, Captain." He turned his ancient spectacles over in his fingers and sighed. "Look, we don't need to wait for the lab results. I know damn well what we're going to find."

Mith spread his hands palm up. "What?"

"We're suffering from protein and vitamin deficiencies. The children particularly are being hit by bone, skin and growth disorders so archaic that the Ship's medical printouts don't even refer to them." He thought of his own grandchild, not four thousand shifts old; when Hollerbach took those slim little legs in his hands he could feel the bones curve… "Now, we don't think there's anything wrong with the food dispensers."

Mith snorted. "How can you be so sure?"

Hollerbach rubbed his eyes again. "Of course I'm not sure," he said, irritated. "Look, Mith, I'm speculating. You can either accept that or wait for the tests.»

Mith sat back and held up his palms. "All right, all right. Go on."

"Very well, then. Of all the Raft's equipment our understanding is, by necessity, greatest of the dispensers. We're overhauling the brutes; but I don't expect anything to be found wrong."

"What, then?"

Hollerbach climbed out of his chair, feeling the familiar twinge in his right hip. He walked to the open door of his office and peered out. "Isn't it obvious? Mith, when I was a kid that sky was blue as a baby's eyes. Now we have children, adults even, who don't know what blue is. The damn Nebula has gone sour. The dispensers are fed by organic compounds in the Nebula atmosphere — and by airborne plants and animals, of course. Mith, it's a case of garbage in, garbage out. The machines can't work miracles. They can't produce decent food out of the sludge out there. And that's the problem."

Behind him Mith was silent for a long time. Then he said, "What can we do?"

"Beats me," said Hollerbach, a little harshly. "You're the Captain."

Mith got out of his chair and lumbered up to Hollerbach; his breath was hot on the old Scientist's neck, and Hollerbach could feel the pull of the Captain's weighty gut. "Damn it, stop patronizing me. What am I supposed to tell the crew?"

Abruptly Hollerbach felt very tired. He reached with one hand for the door frame and wished his chair weren't so far away. "Tell them not to give up hope," he said quietly. "Tell them we're doing all we know how to do. Or tell them nothing. As you see fit."

Mith thought it over. "Of course, not all your results are in." There was a trace of hope in his voice. "And you haven't completed that machine overhaul, have you?"

Hollerbach shook his head, eyes closed. "No, we haven't finished the overhaul."

"So maybe there's something wrong with the machines after all." Mith clapped his shoulder with a plate-sized hand. "All right, Hollerbach. Thanks. Look, keep me informed."

Hollerbach stiffened. "Of course."

Hollerbach watched Mith stride away across the deck, his belly oscillating. Mith wasn't too bright — but he was a good man. Not as good as his father, maybe, but a lot better than some of those who were now calling for his replacement.

Maybe a cheerful buffoon was right for the Raft in its present straits. Someone to keep their spirits up as the air turned to poison—

He laughed at himself. Come on, Hollerbach; you really are turning into an old fart.

He became aware of a prickling over his bald pate; he glared up at the sky. That star overhead was a searing pinpoint, its complex orbit bringing it ever closer to the path of the Raft. Close enough to burn the skin, eh? He couldn't remember a star being allowed to fall so threateningly close before; the Raft should have been shifted long since. He'd have to get on to Navigator Cipse and Ms boys. He couldn't think what they were playing at.

Now a shadow swept across him, and he made out the silhouette of a tree rotating grandly far above the Raft. That would be Pallis, returning from the Belt. Another good man, Pallis… one of the few left.

He dropped his prickling eyes and studied the deck plates beneath his feet. He thought of the human lives that had been expended on keeping this little metal island afloat in the air for so long.

And was it only to come to this, a final few generations of sour sullenness, falling at last to the poisoned air?

Maybe it would be better not to move the Raft out from under that star. Let it all go up in one last blaze of human glory—

"Sir?" Grye, one of his assistants, stood before him; the little round man nervously held out a battered sheaf of paper. "We've finished another test run."

So there was still work to do. "Well, don't stand about like that, man; if you're no use you're certainly no ornament. Bring that in and tell me what it says."

And he turned and led the way into his office.

The Raft had grown in the sky until it blocked out half the Nebula. A star was poised some tens of miles above the Raft, a turbulent ball of yellow fire a mile wide, and the Raft cast a broadening shadow down through miles of dusty air.

Under Pallis's direction Rees and Gover stoked the fire bowls and worked their way across the surface of the tree, waving large, light blankets over the billowing smoke. Pallis studied the canopy of smoke with a critical eye; never satisfied, he snapped and growled at the boys. But, steadily and surely, the tree's rise through the Nebula was moulded into a slow curve towards the Rim of the Raft.

As he worked Rees chanced the wrath of Pallis by drinking in the emergent details of the Raft. From below it showed as a ragged disc a half-mile wide; metal plates scattered highlights from the stars and light leaked through dozens of apertures in the deck. As the tree sailed up to the Rim the Raft foreshortened into a patchwork ellipse; Rees could see the sooty scars of welding around the edges of the nearer plates, and as his eye tracked across the ceiling-like surface the plates crowded into a blur, with the far side of the disc a level horizon.