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."

"Exactly." Seciv nodded, looking pleased. "We could haul ourselves along the Magfield, exactly as we do when we Wave in the Air. Well done, young man."

Muub pulled at his lower lip. "But maybe the Magfield doesn't penetrate the underMantle."

"We believe it does," Seciv said. "The underMantle and the Sea are permeated by charged particles — protons, electrons and hyperons — which sustain the Magfield."

Hosch sneered. "What would we do, attach a pair of false legs to the back?"

Farr — whose imagination seemed to have been caught — said excitedly, "No, you'd Wave using coils of superconductor. Like the anchor-bands. You could move them from inside the Bell, and..."