Part 3

Inside his mind was a slowly growing hatred of the Aliens, and he clung to it tenaciously. They'd denied him his right to be a normal human being--and while their imposed attitudes made it impossible for him to understand the absurd conduct of men, he was beginning to realize that the fault lay with him, and not with the rest of humanity. It was not a pleasant thought.

Fresh guards had replaced the original pair. They swung in behind him, and then stopped at the entrance of the laboratory. He'd insisted that they stay outside, since he wanted no one to watch his experiments with the lizards. Complete ignorance of events was the only sure protection against spies.

He headed around the computer by letting his feet guide him, and reached for the switch. It clicked, just as a voice sounded in front of him.

"Norden, you damned fool! Leave those lights off!"

But they were already on, showing the tall, unmoving figure of Armsworth standing before the cage of the lizards with a knife in his hand.

IV

Norden felt a wave of hate boil up in him, and made no attempt to check it. As he returned Armsworth's stare his mind reacted to the situation before he could realize more than a few of the implications.

Obviously, Armsworth was a spy who knew of the work here, and had come to wreck it. With his rank, it would be easy enough for him to get in. Also, the man stood there with none of the fear he should have shown on being discovered, and Norden felt the sick confirmation of his being a pawn for the Aliens.

But the fact itself gave him some chance. He lifted his arm to the switch, and then dropped it. "The guards would suspect something if I cut it off now," he admitted candidly. "Any suggestions?"

"I could kill the lizards, let you discover me, and chase me out to explode," Armsworth said thoughtfully, without any emotional color to the suggestion. He shook his head.

"I don't know. It's funny they can't trust you to stall off the Miles girl and have to send me here. With replacements scarce, I'd hate to blow up unless it's absolutely necessary."

Then his eyes narrowed in incredulous alarm. "Wait a minute. You weren't supposed to know my identity."

Norden's hand swept up, hit the light switch. His other arm jerked out for the big tongs he had noticed. He heard the spy leap, and recoiled just in time to avoid the rush. His arm came down with the instrument, and there was a solid thud. When he turned the lights on again, Armsworth lay on the floor with a gash across his head an inch deep.

For a moment Norden was only aware of his own harsh breathing. Then, slowly and horribly, the corpse sat up and began hitching along the floor toward the cage of lizards.

Norden bent, picked up the little cage and swung towards the door. He took one step forward, stopped abruptly, and bent again. His hand gripped the collar of the thing on the floor and, straightening, he heaved it up against the light gravity of the Moon.

The thing sailed across the laboratory, heading toward the rear of the heavy protogravity generator. Norden cushioned the cage of lizards against his chest and dropped to the floor in the shelter of the computer.

There was a blast that nearly ruptured his eardrums and the accompanying glare of greenish-yellow light burned through his eyelids into his brain. The floor heaved and shook, while sections of the curved roof began falling. The air gushed upwards, and the floor jarred again as the automatic airseal dropped, cutting off other sections.

Norden jumped toward a plainly marked closet, and threw it open. He yanked down one of the spacesuits stored there for emergency purposes, thrust the lizard cage inside, closed it, and turned on the oxygen.

Adapted to the thin air of Mars, it seemed likely the animals would remain alive. He groped about until he located another suit that would fit, cursed as he found it zippered closed, and finally worked it open. Once in, he sealed it, and headed toward the personnel lock on the big emergency airseal.

He got through just as the guards were about to enter in their own spacesuits, dragging rescue equipment. Miles was with them, waiting impatiently while Norden slipped his helmet off. "Who was it?" he demanded.

"Armsworth," Norden told him. "After he passed the fluoroscope test!"

Miles sighed, but there was no surprise. "Damn! I should have had him checked when he came back from inspecting the other side. They must have had a spy all ready to make the switch as soon as they got him. Or maybe the test doesn't mean anything."

The guards had come back. One of them began to report on what they had seen. Most of the damage had been confined to the roof of the building, and to the big protogravity generator, which apparently had shielded the rest of the equipment.

Norden and Pat, who had finally been called, went inside in their suits to supervise clearing away the debris. Outside, a crew was already erecting a new roof on the laboratory, using prefab sheets. Aside from the generator they had never used, nothing irreplaceable had been hurt. And the two little male lizards were doing well enough. Inside of two hours the laboratory was back in full operation.

By common consent, Pat and Norden abandoned all idea of sleeping. Norden started to draw up a list of new tests, and then went back to the potassium shield. It seemed to produce a very slight quantitative difference in the reaction of the females. He consulted the vague speculations in his own works on possible other spectra, and came back.

The trouble was that he wasn't working with any natural phenomenon, but with life. He grimaced at the twist of his logic, but the sense remained. Something came into the back of his mind from a phrase in Hardwick's notes. It teased him, until his mind almost had it, and then another taboo clamped down on his thoughts.

He fought it out, standing still while Pat stared at him doubtfully. Twice he could feel himself almost black out, but he tracked the taboo down in his mind, pursued it into its lair, and strangled it. It died hard, but left his answer available.

"K-40," he said. His voice was steady, and Pat relaxed, unable to see the complete fatigue inside him. Disciplining himself seemed to be the hardest possible task. "Radio-active potassium isotope. It's supposed to be mixed up somehow with the life processes. Some scientists claim it's essential to life."

She reached for the phone, and spoke into it briefly. Then there was a wait, before she handed it over, and a voice came on. "This is General Dawes at Oak Ridge. Who's calling?"

"William Norden, Project A-sub-zero, Moon Base. I want five pounds of K-40 up here in four hours. Use my top priority and mark the shipment for delivery to me only."

There was the usual few seconds of waiting while the message traveled to Earth, and back. "Five _pounds_?" the voice asked, incredulously.

"Five pounds! And I may want more as fast as it can be gathered."

Pat was on another phone. Before Earth could answer again, there was a click, and General Miles' voice broke in sharply. "This is Miles, Dawes. _Give Norden what he wants._"

A sputter of protest began, but it ended abruptly as Miles' voice reached Earth. The silence was broken by a sigh. "Okay, Norden, we'll get it to you in four hours somehow."

It arrived in less time, and Norden and Pat began the tricky job of getting the highly active elements into a container which was both chemically and radio-actively safe. They clamped it over the cage at last, and watched the pressure on the female cages.

The results weren't spectacular, but they were unquestionable. And later, when they had reduced the amount of K-40 to a thin coating, it still worked. The quantity of potassium made very little difference beyond a certain minimum.

The effects still weren't good enough. They tried painting various substances with the chloride of the potassium, with equally good results and much greater ease of handling. The nitrate was even better to work with.

But it took them until late that night before they learned that coating the nitrate over cleaned iron was a major step forward. Until then it had been all hit and miss, except for vague directional hunches.

Norden looked at Pat, who seemed ready to drop. "Better go back for some rest," he suggested. She shook her head, but did agree to lie down while he began re-checking their results to date. Their best efforts had quieted the excitement of the females by no more than ten percent.

He reduced everything he could to a consistent basis, and added other formulae which might apply from the incomplete relationship tables that strove to reconcile the two recognized spectra. Those might also indicate something about any third spectrum. Either his memory was coming back or his reading of the books and articles was beginning to take effect, he was pleased to notice.

Pat worked the computer, which had fortunately suffered only minor damages, and had been repaired. From the computations, they made the indicated experiments, and fed the results into the machine. This time, it gave only seven suggested answers, with a rough weighing of them. The second one called for one of several organic substances soaked in potassium ferrocyanide and grounded.

While they waited for the chemistry shed to handle that with due precautions on the radio-active isotope, they tried the others. One gave a better than fifty percent reduction, which meant that the females were only mildly crazy.

"Don't they ever relax?" Pat wondered, unwrapping one of the sandwiches Miles had ordered sent in to them.

The female sand lizard's libido mattered less than nothing to Norden at the moment. He was staring at the work he had done in relating hints and fragments of information with pure hunches to get new facts, and realizing that he could never have done that, even before the Aliens had tampered with him. Either he was mysteriously more capable, now that he'd managed to overcome a few of the taboos in his mind, or else the loss of so much of his memory had left his thoughts freer to operate.

"We'll call this the Hardwick spectrum," he decided aloud. "The man was a crackpot cultist, but he was a genius, all the same. And with this, we'll pay those damned Aliens back for what they did to him."

"We wouldn't be able to if you hadn't had time to get the males and yourself into oxygen suits before Armsworth exploded," Pat told him. "They're the only males left alive, now that Mars has been scoured by the Aliens."

He swung around in surprise. "I never...."

The phone saved him from finishing. He hadn't had time to get into a space suit immediately. After the blast he had fumbled around searching for one. And he'd arrived outside the lock without ever having felt discomfort from living in a vacuum for _five full minutes_!

His self-satisfaction vanished, and revulsion took its place. He stared at his body in horror. No human body could have endured such punishment. But he had taken it without noticing it!

Pat came back at a run. "Come on, Bill. A messenger just arrived from Earth with five hundred pounds of K-40!"

"Five hundred?" Norden could almost hear again the amazed voice of General Dawes when he asked for a mere five pounds--a quantity nearly impossible to secure.

Pat's face confirmed his suspicions. Earth couldn't have made five hundred pounds so rapidly.

* * * * *

They found the guards already waiting to take them to where Miles was, and followed them down to the entrance of the explosion testing chamber. Miles was smiling and chatting with a man who appeared to be a perfectly normal rocket pilot, and who seemed bored until he saw Norden. He consulted a picture on some kind of tape recording and stepped forward.

"I have orders to deliver the K-40 to you, Dr. Norden," the pilot said. "But it's pretty bulky in its containers. If you'll come out to the ship and okay it...."

Miles cut in blandly. "I've been explaining the new regulations, Dr. Norden." He winked slightly, with a faint motion toward the chamber.

"Go ahead and clear through," Norden told the pilot. "I'll wait, and then we can look at your cargo. It's a damned nuisance having to hold things up while everyone is X-rayed. But we've new regulations now." He caught Miles' look of approval, and he knew he'd reacted correctly.

The pilot shrugged. "Why not? Let me know if you find any dangerous diseases." He chuckled, and stepped through the entrance, and out toward the fluoroscope set-up.

The picture on the screen was satisfactory and the guards started to relax beside the slits where their guns projected into the chamber. Miles glanced at them, and his voice was urgent, commanding. "_Shoot to miss. And keep getting closer._"

Another screen showed the pilot turning to leave, just as the first bullet splintered the floor a yard from his boots. He jumped back with a terrified gesture. Another bullet came closer, and a third barely missed him. Shock hit his face, and vanished as he turned into a bright splash of greenish-yellow light.

"They over-estimated our production and under-estimated our ability to bluff," Miles said. "Good shooting, men. I'm glad he decided he'd failed the test before you had to shave it closer."

Norden stood staring at the blasted area and back toward the screen that had shown the image of a normal human standing before a fluoroscope. Breathing vacuum for five minutes hadn't hit him as hard. Subconsciously, he'd counted on the fluoroscopic evidence--and it had proved to be a lie.

"He couldn't have been an Alien with that kind of a skeleton!" he whispered.

Miles shook his head. "He wasn't. As near as our cyberneticists could gather, he was some kind of a robot, designed to mix with us. We left automatic televisors on Mars to catch a few telephotos of the Aliens, and they look a little like octopi on stubby legs. Nothing could make them look human."

"But a robot with a human skeleton?" Pat asked.

"It's possible, with enough advanced development. Hide the metal works in the so-called bones and skull, and shape everything else to the right form and transparency. Probably the first ones we caught were meant to mislead us. Hughes swears that any race capable of developing such an advanced cybernetic brain could handle the rest--down to letting him get his energy out of our food."

Miles' face was more fatigued than ever, but he found enough strength for a smile. "Thanks for playing along with me, Bill. Now get back to work, if you can stand it. The chem lab delivered your stuff while you were coming here."

The stuff from the chemists looked like wool, impregnated with the K-40 salt. Pat slashed off a yard of the coarse cloth and draped it around the cage, after a quick check with the Geiger-Mueller counter. She formed a rope of it and connected the cage-cover to the nearest pipe.

And the images of the females in the screens were suddenly still, as if all of them had gone to sleep at once. Pat yanked the cover off and instantly the females were dashing at the gates of their cages again.

Pat let out a yell and reached for the phone. Norden tried to echo her enthusiasm, but there was no resiliency left in him. He stared at the answer to their problems, while part of his mind estimated that the pilots could stand the radioactivity from suits of such cloth long enough to accomplish their purpose, if an undersuit of lead-cloth could be worn also.

But the rest of his mind was in his own private hell. _Robot_, it shouted at him--_robot and spy!_ It was plain enough now that his periods of "relaxation" and review of the day's events had been a mechanism for leaking information to the Aliens. His unexpected and rebellious attempt to end it had been the signal to send Armsworth against the male lizards. Hands-behind-the-head-Norden, he thought--the robot too dumb to recognize the working of an automatic transmitter switch.

He fondled the cloth cover slowly, tasting the anticipation of revenge. The Aliens had taken a man named William Jon Norden from a lonely asteroid, and had drained him of his life history and knowledge. They'd built a poor dupe of a robot, and had sent it out to spy for them, and to believe for a while that it was human and alive. Now let them feel the defeat they'd earned when they built their robot too close to the original.

Then he considered the thin thread on which his hopes rested. He had something that stopped some form of energy from being detected by the lizards--an unknown band-width of an unknown spectrum which might not even be the right one.

He swung around to check Pat's call, but it was too late. The word had already spread, judging by the whoops or rejoicing coming from beyond the laboratory.

V

Norden broke away from the men who refused to listen to his warnings as quickly as possible. Pat had already gone to her bunk, worn out completely by the brief burst of hope, and he headed for his own cubicle. There was no physical fatigue--how could there be in a robot? But his mind was dulled with too many shocks. He dropped to the bunk, and his arms came up automatically.

He forced them down, and this time he was ready when his brain tried to black out on him. The compulsions that acted on him to make him pass on his information to the Aliens were partly under his control.

He managed to sidetrack his thoughts before blacking out, and to keep his arms down. He lay there, cursing himself and the things which had created him, fighting his battle silently, until he knew he had won.

His legs were unsteady when he finally stood up. The effort of will had shocked even his motor control impulses, but the damage was not permanent, and by the time he passed Miles' darkened doorway, he was moving smoothly enough again. He saw surprised looks exchanged by his guards as they followed him back to the laboratory.

"You might as well come in," he told them. "I'll be here all night, and there's nothing secret about my work now. I think there's a deck of cards in the desk over there."

One of them looked and came back, holding the deck and grinning. "Thanks, Doc," he said. "You're all right."

For a second, Norden experienced a warming glow as he turned into his office. He could find some acceptance among men now. Then he grimaced bitterly, as he realized what they'd think of him if they knew the truth about him. It was one thing to ape humanity, quite another to belong.

The article on speculative spectra by the Japanese scientist was still on his desk, and he began poring over it. Almost at once, his mind swerved away on a flight of curiosity about the card game the men had been playing. He pulled it back, and his imagination started in on hatred of the Aliens.

He fought against that too, tempting as it was. He'd licked the compulsion to communicate with them in two hours. There was hope that he could lick the taboo against investigating into a forbidden field. The fact that it was forbidden made it doubly worth studying.

Bit by bit he traced down the mathematics, but in the end the taboo threw him. It required all the effort he could bring to the problem to follow the tricky formulae, and it couldn't be done while fighting the treachery of his own mind. He gave up in disgust, and turned to the computer.

He'd seen Pat use it often enough, and apparently his robot mind was good at memorizing. He searched through the available tapes of information until he came to one that covered the more vital aspects of Einstein's unified field theory.

He fed it in, and began adding the spectra relation data from the books, carefully storing them in the memory circuits of the machine. The mathematics of the article went in next. He made sure the material they had used to locate the screen was still active, and brought it up to date.

Finally he set the machine to deriving all possible extensions of the mathematics he couldn't handle himself.

When that was finished, there was no longer any need to worry about the taboo. The computer had done what he had failed to do, and more. He stared at the sheaf of papers. The assembled material would save years of work on extraspectral radiation. And his suspicion that magnetism was the vital link seemed to be confirmed. It appeared to be something of a universal transformer, when properly handled.

But the machine couldn't tell him what section of the Hardwick spectrum involved life. The field used by the lizards to locate each other lay well up in it, in a band relationship somewhat analogous to the X-rays of the normal spectrum. But if that failed, there was no clue to what might work.

In any new field, one fresh fact could open up tremendous stores of knowledge--but there would always be even greater ones awaiting discovery.

He put in a call to the library for more material on Janiekowski's work with the lizards, and was told that they'd have to secure a tape from Earth. Earth promised a ship with the tape, and other material he'd requested within three hours. There was no questioning of his priorities this time.

Then he glanced at the clock, and was shocked to find it already past noon. He got up impatiently, heading toward the lunch room. It was strange that Pat had failed to join him.

He found her and Miles searching for him in the cafeteria, and one look was enough. Miles motioned Norden to follow him, and led the way to his office. Once there, he closed the door, and threw the decoded dispatches down for Norden to see.

"The Aliens have narrowed the invasion area to ten million miles from Earth," he said wearily. "We've been holding out by a clever tactical subterfuge. Send out a hundred ships near each other, and the Aliens can't handle them all at once. If we're lucky, and spot the first torpedoes, we can trace them back and a few ships may survive long enough to send visual, pattern-seeking atomic torpedoes toward the Alien ship.

"But we can't get closer than a few hundred thousand miles with any life aboard a ship, because the radiation--or whatever it is they use--is fatal so long as they can detect us. You can see why Command rushed through all the screen suits they could, and struck this morning. They had to."

Norden picked up the dispatches, and scanned them grimly. Seven hundred pilots out of twice that many thousand had been screened. A third of the total number had returned--but none of the spared ships had been theoretically protected.

The Aliens had apparently not only spotted all of the protected ships, but had concentrated their torpedo fire on them. The experiment was a complete failure!