The Boomerang Circuit

CHAPTER VIII Dark Barrier

FOR a time Kim sat still and sweat poured out on his skin. Because their chances had seemed slight indeed. To stop a spaceship at transmitter-speed was impossible with manual means, anyhow. It could cross a galaxy in the tenth of a millisecond. So Kim had devised a radiation-operated relay which threw off the drive when the total radiation reaching a sensitive plate in the bow had reached an adjustable total.

If in an ordinary flight the Starshine headed into a sun—unlikely as such an occurrence was—the increased light striking the relay-plate would throw off the drive before harm came. But this time they had needed to approach fatally close to a star. So Kim had reversed the operation of the relay. It would throw off the drive when the amount of light reaching it dropped below a certain minimum. That could happen only if the ship came up behind the planet, so the sun was blacked out by the world's shadowed nightside.

It had happened. The glare was cut off. The transmitter-drive followed. The Starshine floated within a bare few million miles —perhaps less than one million—of a blue-white dwarf star, and the two humans in the ship were alive because they had between them and the sun's atomic furnaces, a planet some six thousand miles in diameter.

"We don't know how our velocity matches this thing," said Kim after an instant. "We could be drifting toward the edge of the shadow. You watch the stars all around. Make sure I head directly for that blackness. When we touch, I'll see what I can find out."

He reversed the ship's direction. He let the Starshine float down backward. The mass of unsubstantial darkness seemed to swell. It engulfed more and more of the cosmos. . . .

A long, long time later, there was a strange sensation in the feel of things. Dona gave a little cry.

"Kim! I feel queer! So queer!"

Kim moved heavily. His body resisted any attempt at motion, and yet he felt a horrible tension within him, as if every molecule were attempting to fly apart from every other molecule. The controls of the ship moved sluggishly. Each part of each device seemed to have a vast inertia. But the controls did yield. The drive did come on. A little later the sensation ended. But both Kim and Dona felt utterly exhausted.

"It—was getting dark, too," said Dona. She trembled.

"When we tried to move," said Kim, "our arms had a tendency to move at right angles to the way we wanted them to, at all the possible right angles at once. That was the edge of the shield, Dona. Now we'll see what we've got."

He uncovered the recording cabinet. There had been no need to set up instruments especially for the analysis of the field. They had been a part of the Starshine's original design for exploration. Now Kim read the records.

"Cosmic-ray intensity went down," he reported, studying the tapes. "The dielectric constant of space changed. It just soared up. The relationship of mass to inertia. That particular gadget never recorded anything significant before, Dona. In theory it should have detected space-warps. Actually, it never amounted to anything but a quantitative measure of gravitation on a planet one landed on. But it went wild in that field! And here! Look!"

He exultantly held out a paper recording. "Glance at that, Dona! See? A magnetometer to record the strength of the magnetic field on a new planet. It recorded the ship's own field in the absence of any other. And the ship's field dropped to zero! Do you see? Do you?"

"I'm afraid not," admitted Dona. But she smiled at the expression on Kim's face.

"It's the answer!" said Kim zestfully. "Still I don't know .v that blasted field is made, but I know now how it works. Neutrons have no magnetic field, but this thing turns them aside. Alpha and beta and gamma radiation do have magnetic fields, but this thing turns them aside, too. And the point is that it neutralizes their magnetic fields, because otherwise it couldn't start to turn them aside. So if we make a magnetic field too strong for the field to counter, it won't be able to turn aside anything in that magnetic area. The maximum force-field strength needed for the planet is simply equal to the top magnetic field the sun may project so far. If we can bury the Starshine in magnetic flux that the force-field can't handle—"

HE GRINNED. He hugged her.

"And there's a loop around the Star-shine's hull for space-radio use," he cried. "I'll run a really big current through that loop and we'll try again. We should be able to put quite a lot of juice through a six-turn loop and get a flux-density that will curl your hair!"

He set to work, beaming. It took him less than half an hour to set up a series-wound generator in the airlock, couple in a thermocell to the loop, so it would cool the generator as the current flowed and thereby reduce its internal resistance.

"Now!" he said. "We'll try once more. The more juice that goes through the outfit, the colder the generator will get and the less its resistance will be, and the more current it will make and the stronger the magnetic field will be."

He flipped a switch. There was a tiny humming noise. A meter-needle swayed over, and stayed.

The Starshine ventured into the black globe below.

Nothing happened. Nothing happened at all.

"The stars are blotted out, Kim," Dona at last said uneasily.

"But you feel all right, don't you?" He grinned like an ape in his delight.

"Why, yes."

"I feel unusually good," said Kim happily.

The vision-screens were utterly blank. The ports opened upon absolute blackness—blackness so dead and absorbent that it seemed more than merely lack of light. It seemed like something horrible pressing against the ports and trying to thrust itself in.-

And, suddenly, a screen glowed faintly, and then another... .

Then there was a greenish glow in the ports, and Dona looked out and down. Above was that blackness, complete and absolute. But below, seen with utter clarity, because of the absence of atmosphere, lay a world. Nothing grew upon it. Nothing moved. It was raw, naked rock with an unholy luminescence. Here and there the glow was brighter where mineral deposits contained more highly active material. The surface was tortured and twisted, in swirled strained writhings of formerly melted rock.

They looked. They saw no sign of human life nor any sign that humans had ever been, there. But after all, even five thousand years of mining on a globe six thousand miles through would not involve the disturbance of more than a fraction of its surface.

"We did it," said Kim. "The shield can be broken through by anything with a strong enough magnetic field. We won't disturb the local inhabitants. They undoubtedly have orders to kill anybody who incredibly man- t ages to intrude. We can't afford to take a chance. We've got to get back to Ades!"

He pointed the Starshine straight up. He d drove her, slowly, at the ceiling of impenetrable black. He worked upon the transmitter-drive relay. He adjusted it to throw the Starshine into transmitter-speed the instant h normal starlight appeared ahead. The ship swam slowly upward. Suddenly there was a momentary impression of reeling, dancing stars. Kim swung the bow about. "Now for Ades!" he said gleefully. "Did you know, Dona, that once upon a time the word Ades meant hell?"

The stars reeled again. . . .

They found Ades. Knowing how, now, it was not too difficult. There were two positions from which it could be detected. One was a position in which it was on a line between the Starshine and the sun. The other was a position in which the invisible planet of the space-ship, and the sun formed the three K points of a right-angled triangle with Ades in the ninety-degree corner.

Kim sent the little ship in a great circle beyond the planet's normal orbit, watching for it to appear where such an imaginary triangle would be formed. The deflected light of the sun would spread out in a circular flat thin plane, and somewhere about the circuit the Starshine had to run through it. It would be a momentary sight only, and it would not be bright; it would be utterly unlike the steady radiance of a normal planet. Such flashes, if seen before, would have been dismissed as illusions or as reflections from within the ship. Even so, it was a long, long time before Dona called out quickly.

"There!" she said, and pointed.

KIM swung the Starshine back. He saw the dim, diffused spectre of sun's reflection. They drove for it, and presently a minute dark space appeared. It grew against the background of a radiant galaxy, and presently was a huge blackness, and the Starshine's space-radio loop was once more filled with a highly improbable electrical amperage by the supercooled generator in the airlock.

The ship ventured cautiously into the black.

And later there were lonely, unspeakably desolate little lights of the lost world down below.

Kim drove for them with a reckless exultation. He landed in the very center of a despairing small settlement which had believed itself dead and damned—or at any rate doomed. He shouted out his coming, and Dona cried out the news that the end of darkness was near, and men came surging toward her to listen. But it was Dona who explained, her eyes shining in the light of the torches men held up toward her.

Kim had gone back into the ship and was using the communicators to rouse out the mayors of every municipality, and to say he had just reached the planet from Terra- nova—there was no time to tell of adventures in between—and he needed atmosphere fliers to gather around him at once, with armed men in them, for urgent business connected with the restoration of a normal state of affairs.

They came swiftly, flittering down out of the blackness overhead, to land in the lights of huge bonfires built by Kim's orders. And Kim, on the communicators, asked for other bonfires everywhere, to help in navigation, and then he went out to be greeted by the bellowing Mayor of Steadheim.

"What's this?" he roared. "No sunlight! No stars! No matter-transmitter! No ships! Our ships took off and never came back! What the devil happened to the universe?"

Kim grinned at him.

"The universe is all right. It's Ades. Somewhere on the planet there's a generator throwing out a force-field. It will have plenty of power, that generator. Maybe I can pick it up with the instruments of the Starshine. But we'll be sure to find it with magnetic compasses. What we want is for everyone to flick their compasses and note the time of swing. We want to find the place where the swings get slower and slower. When we find a place where the compasses point steadily, without a flicker—not even up and down—we'll be at the generator. And everybody put on navigation-lights or there'll be crashes!"

He lifted the Starshine and by communicator kept track of the search. Toward the polar regions was the logical hiding-place for the generator, because there the chilly climate of Ades became frigid and there were no inhabitants. But it was a long search. Hours went by before a signal came from a quarter-way around the globe.

Then the Starshine drove through darkness—but cautiously—with atmosphere-fliers all about. And there was an area where the planet's magnetic field grew weaker and weaker, and then a space in which there was no magnetic field. But in the darkness they could find no sign of a depot!