Hork's expression was hard, and she felt briefly uneasy — she'd been around him long enough now to witness several of his towering rages. But he merely laughed aloud once more. His noisy, exuberant presence was overwhelming in the cramped cabin; Dura felt herself shrink from it, as if escaping into herself. Hork said, "Quite right, captain! And isn't it time you started working the pigs?"

He was right; Dura swiveled in her sling to begin the work. The craft wouldn't be cut loose of the Harbor cable for some time, but they needed to be sure the internal turbine and the magnetic fields were fully functioning. The animals' harness, slung across the width of the cabin, kept the pigs' rears aimed squarely at the wide blades of a turbine. A trough carved from unfinished wood had been fixed a micron or so before the pigs' sketchy, six-eyed faces, and now Dura took a sack of leaves from a locker and filled the trough with luscious vegetable material, crushing the stuff as she worked. Soon the delicious tang of the leaves filled the cabin. Dura was aware of Hork bending over his console, evidently shutting out the scents; as for herself — well, she could all but taste the protons dripping out onto her tongue.

The pigs could barely stand it. Their hexagonal arrays of eyecups bulged and their mouths gaped wide. With grunts of protest they hurled themselves against the unyielding harness toward the leaves, their jetfarts exploding in the cramped atmosphere of the cabin.

Under the steady pressure of the jetfart stream, the broad blades of the turbine began to turn. Soon the sweet, musky smell of pig-fart permeated the Air of the cabin, reminding Dura, if she closed her eyes, of the scents of her childhood, of the Net with its enclosed herd. She scattered a few fragments of food into the grasp of the pigs' gaping maws. Just enough to keep them fed, but little enough to keep them interested in more.

The anatomy of a healthy Air-pig was efficient enough to enable it to generate farts for many days on very little food. Pigs could travel meters allowing as much of their bulky substance to dissolve into fart energy as was required; these five, though terrified and frustrated by the conditions into which they had been penned, should have little problem powering the turbine for as long as the humans needed. And there was a back-up system — a stove powered by nuclear-burning wood — if they were desperate enough to need to risk its heat in the confines of the cabin.

Hork, grunting to himself, experimentally threw switches. The ship shuddered in response, and Hork peered out of the window, gauging the effect of the currents generated in the superconducting hoops.