The crystal roof had been lifted upward and outward many times in the last two centuries. Each time it had been thickened so that Atlantis might more safely climb higher; more safely withstand the possible blows of meteoric pebbles not yet entirely burnt by the thin wisps of air.

And as Atlantis became more useless and more attractive, more and more of the Higher Ones left their estates and factories in the hands of managers and foremen and took up permanent residence on the Sky-Island. All built larger, higher, more elaborately.

And here was still another structure.

Waves were standing by in stolid, duty-ridden obedience. The name applied to the females – if, Plat thought sourly, they could be called that – was taken from the Early English of the days when Earth was divided into nations. There, too, conversion and degeneration had obtained. The old Waves had done paper work behind the lines. These creatures, still called Waves, were front-line soldiers.

It made sense, Plat knew. Properly trained, women were more single-minded, more fanatic, less given to doubts and remorse than ever men could be.

They always had Waves present at the scene of any building, because the building was done by Lower Ones, and Lower Ones on Atlantis had to he guarded. Just as those on the Surface had to he cowed. In the last fifty years alone, the long-range atomic artillery that studded the underside of Atlantis had been doubled and tripled.

He watched the girder come softly down, two men yelling directions to each other as it settled in place. Soon there would be no further room for new buildings on Atlantis.

The idea that had nudged his unconscious mind earlier in the day gently touched his conscious mind.