Toba studied her, cautious but with traces of concern. "Are you all right?"

She tried to keep her voice steady. "I think so. I'm just a little taken aback by the speed of this thing, I suppose."

He frowned and squinted out through his window. "We're not going so fast. Maybe a meter an hour. After all, it's not as if we've got to work across the Magfield; we're simply following the flux lines home... To my home, anyway. And, this far downflux, the pigs are getting back the full strength they'll have at the Pole. There they could reach maybe twice this speed, with a clear run." He laughed. "Not that there's any such thing as a clear run in Parz these days, despite the ordinances about cars inside the City. And the top teams..."

"I've never been in a car before," she hissed, her teeth clenched.

He opened his mouth, and nodded. "No. True. I'm sorry; I'm not very thoughtful." He mused, "I guess I'd find it a little disconcerting if I'd never ridden before — if I hadn't been riding since I was a child. No wonder you're feeling ill. I'm sorry; maybe I should have warned you. I..."

"Please stop apologizing."

"Anyway, we've made good time. Considering it's such a hell of a long way from the Pole to my ceiling-farm." His round face creased with anger. "Humans can't survive much more than forty, fifty meters from the Pole. And my ceiling-farm is right on the fringe of that, right on the edge of the hinterland of Parz. So far upflux the Air tastes like glue and the coolies are weaker than Air-piglets... How am I supposed to make a living in conditions like that?" He looked at her, as if expecting an answer.

"What's a meter?"

"...A hundred thousand mansheights. A million microns." He looked deflated, his anger fading. "I don't suppose you know what I'm talking about. I'm sorry; I..."

"How deep is the Mantle?" she asked impulsively. "From Crust to Quantum Sea, I mean."

He smiled, his anger evaporating visibly. "In meters, or mansheights?"

"Meters will do."

"About six hundred."

She nodded. "That's what I've been taught, too."

He studied her curiously. "You people know about things like that?"

"Yes, we know about things like that," she said heavily. "We're not animals; we educate our children... even though it takes most of our energy just to keep alive, without clothes and cars and Air-boxes and teams of captive Air-pigs."

He winced. "I won't apologize again," he said ruefully. "Look... here's what I know." Still holding his reins loosely, he cupped his long-fingered, delicate-looking hands into a ball. "The Star is a sphere, about twenty thousand meters across."

She nodded. Two thousand million mansheights.

"It's surrounded by the Crust," he went on. "There's three hundred meters of that. And the Quantum Sea is another ball, about eighteen thousand meters across, floating inside the crust.

She frowned. "Floating?"