"Well," Sheen said briskly, "at least Jame isn't barring you from the Quartermaster's any more."

"We should be grateful for small mercies." He took a sip from his bowl and sighed. "Not so small, maybe…" He indicated the approaching plate. "You miners do seem to have accepted us a lot more easily since the first Boneys arrived."

"I can understand that. Perhaps the presence of the Boneys shows the rest of us how much we have in common."

"Yes."

The Belt's rotation carried the Quartermaster's beneath the approaching plate once again. Sheen could see that the little craft carried three Boneys, two men and a woman. They were all squat and broad, and they wore battered tunics provided by the Belt folk. Sheen had heard legends of what they chose to wear on their home worldlet… She found herself shuddering again.

The Belt was being used as a way station between the Bone world and the Raft; Boneys traveling to the Raft would stay here for a few shifts before departing on a supply tree. At any one time there was, Sheen reminded herself, only a handful of Boneys scattered around the Belt… but most miners felt that handful was too many.

The Boneys stared down at her, thick jaws gaping. One of the men caught Sheen's eye. He winked at her and rolled his hips suggestively. She found her food rising to her throat; but she held his stare until the plate had passed over the Belt's narrow horizon. "I wish I could believe we need those people," she muttered.

Grye shrugged. "They are human beings. And, according to Rees, they didn't choose the way they live. They have just tried to survive, as we all must do… Anyway, we might not need them. Our work with the Moles on the star kernel is proceeding well."

"Really?"

Grye leaned closer, more confident now that the conversation had moved onto a topic he knew about. "You understand what we're trying to do down there?"

"Vaguely…"

"You see, if Rees's gravitational slingshot idea is going to work we will have to drop the Raft onto a precise trajectory around the Core. The asymptotic direction is highly sensitive to the initial conditions—"

She held up her hands. "You'd better stick to words of one syllable. Or less."

"I'm sorry. We're going into a tight orbit, very close to the Core. The closer we pass, the more our path will be twisted around the Core. But the differences for a small deviation are dramatic. You have to imagine a pencil of neighboring trajectories approaching the Core. As they round the singularity they fan out, like unraveling fibers; and so a small error could give the Raft a final direction very different from the one we want."

"I understand… I think. But it doesn't make much difference, surely? You're aiming at a whole nebula, a target thousands of miles wide."

"Yes, but it's a long way away. It's quite a precise piece of marksmanship. And if we miss, by even a few miles, we could end up sailing into empty, airless space, on without end…"

"So how is the Mole helping?"

"What we need to do is work out all the trajectories in that pencil, so we can figure out how to approach the Core. It takes us hours to work the results by hand — work which, apparently, was performed by slavelike machines for the original Crew. It was Rees who had the idea of using the Mole brains."

Sheen pulled a face. "It would be."

"He argued that the Moles must once have been flying machines. And if you look closely you can see where the rockets, fins and so on must have fitted. So, argued Rees, the Moles must understand orbital dynamics, to some extent. We tried putting our problems to a Mole. It took hours of question-and-answer down there on the kernel surface… but at last we started getting usable results. Now the Mole provides concise answers, and we're proceeding quickly."

She nodded, juggling her drink. "Impressive. And you're sure of the quality of the results?"

He seemed to bridle a little. "As sure as we can be. We've checked samples against hand calculations. But none of us are experts in this particular field." His voice hardened again. "Our Chief Navigator was Cipse, you see."

She could think of no reply. She drained the last of her globe. "Well, look, Grye, I think it's time I—"

"Now, then, where can old Quid take a drink around here?»

The voice was low and sly. She turned, startled, and found herself looking down at a wide, wrinkled face; a grin revealed rotten stumps of teeth, and black eyes traveled over her body. She couldn't help but shrink away from the Boney. Vaguely she was aware of Grye quailing beside her. "What… do you want?"

The Boney stroked a finely carved spear of bone. His eyes widened in mock surprise. "Why, darling, I've only just arrived, and what kind of welcome is that? Eh? Now that we're all friends together…" He took a step closer. "You'll like old Quid when you get to know him—"

She stood her ground and let her disgust show in her face. "You come any nearer to me and I'll break your bloody arm."

He laughed evenly. "I'd be interested to see you try, darling. Remember I grew to my fine stature in high-gee… not this baby-soft micro gravity you have here. You're muscled very attractively; but I bet your bones are as brittle as dead leaves." He looked at her acutely. "Surprised to find old Quid using phrases like 'micro gravity,' girl? I may be a Boney, but I'm not a monster; nor am I stupid." He reached out and grabbed her forearm. His grip was like iron. "It's a lesson you evidently need to learn—"

She thrust at the wall of the Quartermaster's with both legs and performed a fast back flip, shaking free his hand. When she landed she had a knife in her fist.

He held up his hands with an admiring grin. "All right, all right…" Now Quid turned his gaze on Grye; the Scientist clutched his drink globe to his chest, trembling. "I heard what you were saying," Quid said. "All that stuff about orbits and trajectories… But you won't make it, you know.»

Grye's cheeks quivered and stretched, "What do you mean?"

"What are you going to do when you're riding your bit of iron, down there by the Core himself — and you find you're on a path that isn't in your tables of numbers? At the critical moment — at closest approach — you'll have maybe minutes to react. What will you do? Turn back and draw some more curves on paper? Eh?"

Sheen snorted. "You're an expert, are you?"

He smiled. "At last you're recognizing my worth, darling." He tapped his head. "Listen to me. There's more on orbits locked in here than on all the bits of paper in the Nebula."

"Rubbish," she spat.

"Yes? Your little friend Rees doesn't think so, does he?" He hefted his spear in Ms right hand; Sheen kept her eyes on the spear's bone tip. "But then," Quid went on, "Rees has seen what we can do with these things—"

Abruptly he twisted so that he faced the star kernel; with surprising grace he hurled the spear. The weapon accelerated into the five-gee gravity well of the kernel. Moving so fast that it streaked in Sheen's vision, it missed the iron horizon by mere yards and twisted behind the star—

— and now it emerged from the other side of the kernel, exploding at her like a fist. She ducked, grabbing for Grye; but the spear passed a few yards above her head and sailed away into the air.

Quid sighed. "Not quite true. Old Quid needs to get his eye in. Still—" He winked. "Not bad for a first try, eh?" He prodded Grye's sagging paunch. "Now, that's what I call orbital dynamics. And all in old Quid's head. Astonishing, isn't it? And that's why you need the Boneys. Now then, Quid needs his drink. See you later, darling…»

And he brushed past them and entered the

Quartermaster's.

Gord shoved his thinning blond hair from his eyes and thumped the table. "It can't be done. I know what I'm talking about, damn it."

Jaen towered over the little engineer. "And I'm telling you you're wrong."