Hosch laughed out loud. “And where do the farts come from, upfluxer? You?”

Seciv frowned, his crumpled hair waving. “You could mimic the internal operation of the pig’s anatomy. The car could carry tanks of Air, heated by a stock of wood in a nuclear-burning boiler and expelled through a valve orifice.” With a delicate finger he reached out and poked at one flabby fin, tentatively. “You could even make an attempt at steering, by mounting these fins on gimbals worked from inside the craft. And the fart nozzles could be made directional, with a little ingenuity.” The old man nodded approvingly to Adda. “A practical suggestion in many respects.”

Adda — despite himself, Dura realized — swelled at the praise; Hosch looked disgruntled.

Farr said seriously, “But how could it survive the underMantle? Adda, I learned in the Bells that it’s not pressure alone that would destroy such a craft, by crushing it…” He snapped his fist closed suddenly, making Dura flinch; she wondered where he’d learned such crude dramatic tricks. Farr went on, “Nuclear matter — ordinary matter — would dissolve.”

Hosch said rapidly, “Well, of course it would. Anyone with a fingernail of experience knows that. Our Bells are protected from the pressure by magnetic fields sent down from the turbines in the City.”

Seciv Trop shook his head. “That’s a misapprehension, Supervisor. To be precise, the Bells are fed by electrical currents which are generated in the Harbor… but the protective magnetic shell is generated at the Bell itself, by superconducting hoops which girdle the Bell.”

Hosch looked the old man up and down. “You’re a Fisherman, I suppose. We must have been on different shifts…”

Muub touched Hosch’s shoulder. “Seciv designed the current generation of Bells — the Bells you ride every day. Hosch, your life depends upon his expertise; it suits you ill to mock him.”

Hosch subsided. “Well, what of it? The boy’s point stands.”

Seciv seemed impervious to offense. “One would simply need to gird this artificial pig around with superconducting hoops, and carry equipment to generate the magnetic field from within.” He frowned. “Of course, the bulk of the craft would be increased.”

Dura asked, “Wouldn’t it get hot inside the wooden pig, with nuclear burning going on all the time?”

Seciv nodded. “Yes, that would be a difficulty… though not in itself insurmountable. A more serious problem would be the supply of propellent Air. Compression ratios in even our best-made tanks are not very high. Sufficient for a jaunt to the ceiling-farms in an Air-car, but hardly enough for an expedition of this magnitude.” He eyed Adda sadly. “Again, perhaps this could be overcome. But there are two far more devastating flaws. First, a lack of stability. There is more to an Air-pig than an anus and a few fins, after all. The pig has six eyes to guide it…”

“Well,” Adda said defensively, “you could have six windows of clearglass. Or more.”

“Perhaps. But the windows would each be manned by a pilot — yes? — who would then have to relay instructions to a crew — five or six men who would haul laboriously at the directing fins, hoping to adjust the motion. Adda, your wooden pig would flounder in the Air, I fear.”

Dura said, “But you don’t have to use fins. The thing doesn’t have to be exactly like a pig, after all. Maybe we could use jetfarts, coming from the sides of the pig.”

“Yes.” Muub looked thoughtful. “That could be far more precise.”

Seciv smiled indulgently. “Still, I would expect instability. Besides, I fear my second objection is fatal.”

Adda glared at him, his eye-leech slithering across his cheek.

“Your mode of propulsion could not work within the underMantle, let alone the Quantum Sea. In high-pressure conditions Air could not be expelled; it would be forced back into the body of the pig.”

Hosch scratched his head. “I hate to be constructive about this stupid idea,” he said, “but couldn’t you throw a magnetic field away from the pig’s hull? Then the farts would be expelled into Air at normal pressure.”

Seciv looked at him and ran bony fingers through his scraps of hair, evidently searching for a simple explanation. “But the expelled Air would still be inside the magnetic field, which in turn would be attached to the ship through the field lines. The Air would push at the magnetic shell, which would drag back the ship. It is a matter of action and reaction, you see…”

Muub waved him to silence. “I think we can take your word for it, Seciv.” He smiled at Adda. “Sir, the consensus seems to be that we can’t proceed with your suggestion; but it was ingenious, and perhaps — do you agree, Seciv? — some aspects of it may survive in a final design. Also, it sounds to me as if we could use this idea to make Air-cars of a different design from those we have at present — Air-cars which wouldn’t need pigs to draw them. None of the problems we’ve talked about would arise if the craft operated in the free Air, after all.”

Adda, clutching his retrieved pig with his one free arm, looked inordinately pleased with himself. Dura nudged him and said quietly, “You’re enjoying this. You’re forgetting you’re a miserable old bugger. You’ll confuse them.”

Adda glared at her. “Well? Who’s next? This Fisherman’s been so clever about my suggestions; now let’s hear what he has to say.”

“Indeed. Hosch?”

The Harbor supervisor spread his empty hands, speaking only to Muub. “My idea is straightforward and I don’t need to send pigskins flying around to describe it. I say we stick to what we know. I say we extend the Spine… but build it as long as we need it to be, down into the underMantle.”

Seciv Trop rubbed his chin. “Well, that has the merit of familiarity, as you say. The wooden Spine would need protecting against dissolution in the underMantle, but we could use superconducting coils to achieve that, as we do now… But what an awesome undertaking it would be. I doubt if such a Spine could sustain its structural integrity on the lengthscale required. And it might affect the stability of the City itself. Could the anchor-bands sustain our position, here at the Pole, with such a counterweight?”

Muub was shaking his head. “Hosch, we can’t conceivably spare the resources for this. You must know the timber convoys from the Crust have dried up since the Glitch, so we’re not getting the wood. And we haven’t the manpower to spare, in any case…”

“Besides,” Dura said, “what if a Glitch hit? The Spine would be so fragile it would be destroyed in moments.”

Hosch folded his arms and crossed his legs, turning his wiry body into a ball of finality. “Then it’s impossible. We may as well stop wasting our time and tell Hork so.”

Muub turned to him. “Frankly, Hosch, I won’t be sorry if that is our conclusion. I’d rather not waste any more time and effort on this fool’s errand than I have to.”

“Oh, no.” Seciv Trop’s creased face showed irritation. “We haven’t reached such a conclusion at all. We’ve merely eliminated possibilities. And we do, perhaps, have some of the elements of a workable solution.”

Muub looked sour, and he pulled at a thread in his robe. “Go on.”

“First, we know that this hypothetical device — this new, free-floating Bell — will need a protective magnetic field, to keep it from dissolution, and some means of propulsion. It will have to be self-sustaining; our traditional methods cannot be extended to such depths, so we’ve ruled out supply from the City. So the device would have to carry a simple turbine to generate a protective field.”

“How would it move?” Dura asked. “I thought you said that jetfarts couldn’t work.”

“And so they couldn’t,” said Seciv. “But there are other means of propulsion…”

“Waving,” said Farr, his round face animated. “What about that? Maybe we could make a Bell that could swim freely, a Bell that could Wave.”