"Now—where the hell did that come from?" panted Wentworth.
Then, abruptly, everything went black. There was darkness. Absolute, opaque, blinding night.
For perhaps two seconds it was unbroken. Then Haynes, still in the flier, pushed the button that turned on the emergency landing-lights. Twin beams of some hundreds of thousands candlepower lashed out, and recoiled from polished metal, and spread about and were reflected and re-reflected. There was a metal roof atop the circular metal wall. Men and flier and clumps of skit-trees were sealed up in a monstrous metal cylinder.
Wentworth swore. Then he cried furiously:
"It isn't so! It simply can't be so!"
He marched angrily to the nearest of the metal walls. Twin shadows of his figure were cast on before him by the landing-light beams. Weird reflections of the shadows and the lights—distorted crazily by the polished surface—appeared on every hand.
He reached the metal wall. He pulled out his flame-pistol and tapped at it. The wall was solid. He backed off five paces and sent a flame-pistol beam at it. The flame splashed from the metal in a coruscating shower. But nothing happened. Absolutely nothing. When he turned off the pistol the metal was utterly unmarred. It was not even red-hot.
Haynes said absurdly:
"The sleeping beauty woke up, Wentworth. What's the matter?"
He saw Wentworth gazing with stupefaction at a place where the metal cylinder touched ground. There was the beginning of a circular clump of skit-trees. And he saw a stalk at a slight angle. It came out of the metal wall. The skit-trees were in the wall. They came out of it. He saw another that went into it.
He went back to the flier and climbed in. He turned the communicator up to maximum power. The racket that came out of it was deafening. He punched the call-button. Again and again and again. Nothing happened. He turned the set off.
The dead stillness which followed was daunting.
"Well?" said Haynes.
"It's impossible," said Wentworth, "but I can explain everything. That wall isn't real."
"Then we ram through it?"
"We'd kill ourselves!" Wentworth told him exasperatedly. "It's solid!"
"Not real, but solid?" asked Haynes. "A bit unusual, that. When I get back to Earth and am a happily married man, I'll try to have a more plausible story than that to tell my wife if I ever come home late—not that I ever will."
Wentworth looked at him. And Haynes grinned. But there was sweat on his face. Wentworth grunted.
"I'm scared too," he said sourly, "but I don't make bad jokes to cover up. This can be licked. It's got to be!"
"What is it?"
"How do I know?" demanded Wentworth. "It makes sense, though. A city that vanishes and re-appears—apparently without anybody in it. That doesn't happen. This can—this tank we're in. There wasn't any machinery around to put up a wall like this. And the top wasn't heaved into place. It wasn't lowered down to seal us in. It didn't slide into position. One instant it wasn't there, and the next instant it was. Like something that—hm— had materialized out of nowhere. Maybe that's it! And the city was the same sort of trick! Maybe that's the secret of this whole civilization we're trying to trace."
His voice echoed weirdly against the metal ceiling on every hand.
"What's the secret?"
"Materializing things! Making a—synthetic sort of matter! Making—well—force-fields that look and act like substance. Of course! If you can generate a building, why build one? We can make a magnetic field with a coil of wire and an electric current. It's just as real as a brick. It's simply different. We can make a picture on a screen. It's just as real as a painting. It's just different. Suppose we could make something like a magnetic field, with shape and coloring and solidity! Why not solidity? Given the trick, it should be as easy as shape or color. . . . If we had a trick like that and wanted to stop some visitors from outer space, we'd simply make the solid image of a can around them! It would be made with energy, and all the energy applied to it would flow to any threatened spot. It would draw power to fight any stress that tried to destroy it. Of course! And why should we build cities? We'd clear a place for them and generate them and maintain them simply by supplying the power needed to keep them in being! We'd make force-fields in the shape of machines, to dig canals or pile up dams. . . ."
He had raised his voice as he spoke. The solid walls and roof made echoes which clanged. He stopped short. Haynes said calmly:
"Then there wouldn't be any artifacts. When a city was abandoned, it would be wiped out as completely as the picture on a theatre-screen when the play is done with. But Wentworth—"
"Eh?"
"If we had that trick, and we'd captured some meddle-some strangers from outer space by clapping a can over them, what would we do?" He paused. "In other words, what comes next for us?"
Wentworth clamped his teeth together.
"Get in the pilot's seat," he commanded, "and put your finger on the vertical flight button. When you see light, stab it down so we'll shoot straight up! If we trapped somebody, and if we lifted it, we'd have something worse than a trap to take care of them with. They'd do the same—and they've got what it should take!"
Silence. Haynes' voice:
"Such as?"
"I saw one Thing this morning," said Wentworth grimly. "I don't like to think about it. If they're bringing it over to snap us up when this can is lifted off of us . . . You keep your finger on the flight-button! That Thing was bigger than the Galloping Cow! I'll try to tip McRae what's happened."
He settled down by the communicator. Every ten minutes he tried to call the expedition's ship. Every time there came a monstrous roar of static as the set came on, and no other sound at all. Aside from that, nothing happened. Absolutely nothing. The flier lay on the ground with an unnatural assortment of reflected and re-reflected light beams from the twin landing-lamps. There were four clumps of skit-trees sharing the prison with the flier and the men.
Silence. Stillness. Nothing. . . . Every ten minutes Wentworth called the Galloping Cow.
It was an hour and a half before there came an answering when Wentworth made his call.
" . . . llo!" came McRae's voice through the crackling static. "Down in. . . . gain. . . . no sign. . . . sort anywhere. . . ."
"Get a directional on me!" snapped Wentworth. "Can you hear me above the static?"
"What stat. . . . oice perfectly clear. . . ." came McRae's booming. "Keep. . . . talking. . . ."
Wentworth blinked. No static at the Galloping Cow! When his ears were practically deafened? Then it made sense. All of it!
"I'll keep talking," he said fervently. "Use the directional and locate me. But don't try to help me direct. Take a bearing from where you find me to where a fifty-foot dirt embankment sticks out from a mountain-spur to the north. Get on that line and you'll hear the static, all right! It's in a beam coming right here at me! Follow that static back to the mountains, and when you find where it's being projected from, you'll find some skit-tree planters with all the artifacts your little heart desires! Only maybe you'll have to blast them. . . ."
He swallowed.
"It makes sense," he went on more calmly. "They built up a civilization based on generating instead of building the things they wanted to use. Our force-fields are globular, because the generator's inside. If you want a force-field to have a definite shape, you have to generate it differently. Their cities and their machines weren't substance, though they were solid enough. They were force-fields! The generators were off at a distance, throwing the force-field they wanted where they needed it. They projected solidities like we project pictures on a screen. They projected their cities. Their tools. Probably their spaceships too. That's why we never found artifacts! We looked where installations had been, instead of where they were generated and flung to the spot where they were wanted. There's a beam full of static coming from those mountains—"