he eased the port fan into fine pitch, and she began to curve slowly to the right. When she was clear of the embarkation building, he straightened her out and pushed the throttle forward.
She handled very well, when one considered the complete novelty of her design. There had been no millennia of trial and error here, stretching back to the first neolithic man who ever launched a log out into a stream. Selene was the very first of her line, created in the brains of a few engineers who had sat down at a table and asked themselves: "How do we build a vehicle that will skim over a sea of dust?"
Some of them, harking back to Ole Man River, had wanted to make her a stern-wheeler, but the more efficient submerged fans had carried the day. As they drilled through the dust, driving her before them, they produced a wake like that of a high-speed mole, but it vanished within seconds, leaving the Sea unmarked by any sign of the boat's passage.
Now the squat pressure-domes of Port Roris were dropping swiftly below the sky line. In less than ten minutes, they had vanished from sight: Selene was utterly alone. She was at the center of something for which the languages of mankind have no name.
As Pat switched off the motors and the boat coasted to rest, he waited for the silence to grow around him. It was always the same; it took a little while for the passengers to realize the strangeness of what lay outside. They had crossed space and seen stars all about them; they had looked up - or down - at the dazzling face of Earth, but this was different. It was neither land nor sea, neither air nor space, but a little of each.
Before the silence grew oppressive - if he left it too long, someone would get scared - Pat rose to his feet and faced his passengers.
"Good evening, ladies and gentlemen," he began. "I hope Miss Wilkins has been making you comfortable. We've stopped here because this is a good place to introduce you to the Sea - to give you the feel of it, as it were."
He pointed to the windows, and the ghostly grayness that lay beyond.
"Just how far away," he asked quietly, "do you imagine our horizon is? Or, to put it in another way, how big would a man appear to you if he was standing out there where the stars seem to meet the ground?"
It was a question that no one could possibly answer, from the evidence of sight alone. Logic said, "The Moon's a small world - the horizon must be very close." But the senses gave a wholly different verdict. "This land," they reported, "is absolutely fiat, and stretches to infinity. It divides the Universe in twain; for ever and ever, it rolls onward beneath the stars.. .."
The illusion remained, even when one knew its cause. The eye has no way of judging distances when there is nothing for it to focus upon. Vision slipped and skidded helplessly on this featureless ocean of dust. There was not even - as there must always be on Earth - the softening haze of the atmosphere to give some hint of nearness or remoteness. The stars were unwinking needle points of light, clear down to that indeterminate horizon.
"Believe it or not," continued Pat, "you can see just three kilometers - or almost two miles, for those of you who haven't been able to go metric yet. I know it looks a couple of light. years out to the horizon, but you could walk there in twenty minutes, if you could walk on this stuff at all."
He moved back to his seat, and started the motors once more.
"Nothing much to see for the next sixty kilometers," he called over his shoulder, "so we'll get a move on."
Selene surged forward. For the first time, there was a real sensation of speed. The boat's wake became longer and more disturbed as the spinning fans bit fiercely into the dust. Now the dust itself was being tossed up on either side in great ghostly plumes; from a distance, Selene would have looked like a snowplow driving its way across a winter landscape, beneath a frosty moon. But those gray, slowly collapsing parabolas were not snow, and the lamp that lit their trajectory was the planet Earth.
The passengers relaxed, enjoying the smooth, almost silent ride. Every one of them had traveled hundreds of