Something huge moved in the black depths below Dallen, startling him and causing Cona to jump backwards from the rail. After a second he identified it as an interportal freighter slipping through space only fifty metres or so beneath his feet, like a silent leviathan swimming for the opposite shore of a black lake. His gaze followed the ship until it was lost in the mirages which overlay the more distant parts of the diaphragm field. At the far side of the kilometre-wide aperture was the space terminal where he would soon embark for Earth. Its passenger buildings and warehouses were a dominant feature of the scene, even though the principal installations — the giant docking cradles for starships — projected downwards into the void and were not readily visible.

"This place bothers me," Cona said. "Everything's more natural in Bangor."

Dallen knew she was referring to the fact that their home town of Bangor, 16,000 kilometres into Orbitsville's interior, was situated in Earth-like hilly terrain. Its official altitude was close to a thousand metres, which meant that amount of sedimentary rock had accumulated there in the Orbitsville shell, but Dallen understood that the geological structure counted for little. Without the enclosing skin of ylem, the enigmatic material of which the vast sphere was formed, the inner layer of rock, soil and vegetation would quickly succumb to instabilities and fly apart. It was an uneasy thought, but one which disturbed only visitors and newly arrived settlers. Anybody who had been born on Orbitsville had total faith in its permanence, knew it to be more durable than mere planets.