One by one, the figures wheeling about the ship outside waved arms or cilia and fell back, coasting down the slope of the sandbar toward the familiar world, dwindling and disappearing. There was at last only one single Euglena, half-plant cousin of the protos, forging along beside the spaceship into the marches of the shallows. It loved the light, but finally it, too, was driven away into deeper, cooler waters, its single whiplike tentacle undulating placidly as it went. It was not very bright, but Lavon felt deserted when it left.
Where they were going, though, none could follow.
Now the sky was nothing but a thin, resistant skin of water coating the top of the ship. The vessel slowed, and when Lavon called for more power, it began to dig itself in among the sand-grains and boulders.
“That’s not going to work,” Shar said tensely. “I think we’d better step down the gear-ratio, Lavon, so you can apply stress more slowly.”
“All right,” Lavon agreed. “Full stop, everybody. Shar, will you supervise gear-changing, please?”
Insane brilliance of empty space looked Lavon full in the face just beyond his big mica bull’s-eye. It was maddening to be forced to stop here upon the threshold of infinity; and it was dangerous, too. Lavon could feel building in him the old fear of the outside. A few moments more of inaction, he knew with a gathering coldness at the pit of his stomach, and he would be unable to go through with it.
Surely, he thought, there must be a better way to change gear-ratios than the traditional one, which involved dismantling almost the entire gear-box. Why couldn’t a number of gears of different sizes be carried on the same shaft, not necessarily all in action all at once, but awaiting use simply by shoving the axle back and forth longitudinally in its sockets? It would still be clumsy, but it could be worked on orders from the bridge and would not involve shutting down the entire machine—and throwing the new pilot into a blue-green funk.
Shar came lunging up through the trap and swam himself to a stop.
“All set,” he said. “The big reduction gears aren’t taking the strain too well, though.”
“Splintering?”
“Yes. I’d go it slow at first.”
Lavon nodded mutely. Without allowing himself to stop, even for a moment, to consider the consequences of his words, he called: “Half power.”
The ship hunched itself down again and began to move, very slowly indeed, but more smoothly than before. Overhead, the sky thinned to complete transparency. The great light came blasting in. Behind Lavon there was an uneasy stir. The whiteness grew at the front ports.
Again the ship slowed, straining against the blinding barrier. Lavon swallowed and called for more power. The ship groaned like something about to die. It was now almost at a standstill.
“More power,” Lavon ground out.
Once more, with infinite slowness; the ship began to move. Gently, it tilted upward.
Then it lunged forward and every board and beam in it began to squall.
“Lavon! Lavon!”
Lavon started sharply at the shout. The voice was coming at him from one of the megaphones, the one marked for the port at the rear of the ship.
“Lavon!”
“What is it? Stop your damn yelling.”
“I can see the top of the sky! From the other side, from the top side! It’s like a big flat sheet of metal. We’re going away from it. We’re above the sky, Lavon, we’re above the sky!”
Another violent start swung Lavon around toward the forward port. On the outside of the mica, the water was evaporating with shocking swiftness, taking with it strange distortions and patterns made of rainbows.
Lavon saw Space.
It was at first like a deserted and cruelly dry version of the bottom. There were enormous boulders, great cliffs, tumbled, split, riven, jagged rocks going up and away in all directions, as if scattered at random by some giant.
But it had a sky of its own—a deep blue dome so far away that he could not believe in, let alone compute, what its distance might be. And in this dome was a ball of reddish fire that seared his eyeballs.
The wilderness of rock was still a long way away from the ship, which now seemed to be resting upon a level, glistening plain. Beneath the surface-shine, the plain seemed to be made of sand, nothing but familiar sand, the same substance which had heaped up to form a bar in Lavon’s own universe, the bar along which the ship had climbed. But the glassy, colorful skin over it—
Suddenly Lavon became conscious of another shout from the megaphone banks. He shook his head savagely and asked, “What is it now?”
“Lavon, this is Tol. What have you gotten us into? The belts are locked. The diatoms can’t move them. They aren’t faking, either; we’ve rapped them hard enough to make them think we were trying to break their shells, but they still can’t give us more power.”
“Leave them alone,” Lavon snapped. “They can’t fake; they haven’t enough intelligence. If they say they can’t give you more power, they can’t.”
“Well, then, you get us out of it,” Tol’s voice said frightenedly.
Shar came forward to Lavon’s elbow. “We’re on a space-water interface, where the surface tension is very high,” he said softly. “This is why I insisted on our building the ship so that we could lift the wheels off the ground whenever necessary. For a long while I couldn’t understand the reference of the history plates to ‘retractable landing gear,’ but it finally occurred to me that the tension along a space-water interface—or, to be more exact, a space-mud interface—would hold any large object pretty tightly. If you order the wheels pulled up now, I think we’ll make better progress for a while on the belly-treads.”
“Good enough,” Lavon said. “Hello below—up landing gear. Evidently the ancients knew their business after all, Shar.”
Quite a few minutes later—for shifting power to the belly treads involved another setting of the gear box—the ship was crawling along the shore toward the tumbled rock. Anxiously, Lavon scanned the jagged, threatening wall for a break. There was a sort of rivulet off toward the left which might offer a route, though a dubious one, to the next world. After some thought, Lavon ordered his ship turned toward it.
“Do you suppose that thing in the sky is a ‘star’?” he asked. “But there were supposed to be lots of them. Only one is up there—and one’s plenty for my taste.”
“I don’t know,” Shar admitted. “But I’m beginning to get a picture of the way the universe is made, I think. Evidently our world is a sort of cup in the bottom of this huge one. This one has a sky of its own; perhaps it, too, is only a cup in the bottom of a still huger world, and so on and on without end. It’s a hard concept to grasp, I’ll admit. Maybe it would be more sensible to assume that all the worlds are cups in this one common surface, and that the great light shines on them all impartially.”
“Then what makes it seem to go out every night, and dim even in the day during winter?” Lavon demanded.
“Perhaps it travels in circles, over first one world, then another. How could I know yet?”
“Well, if you’re right, it means that all we have to do is crawl along here for a while, until we hit the top of the sky of another world,” Lavon said. “Then we dive in. Somehow it seems too simple, after all our preparations.”
Shar chuckled, but the sound did not suggest that he had discovered anything funny. “Simple? Have you noticed the temperature yet?”