by Larry Niven
“Photosynthesis. That’s where all the carbon dioxide went.”
“Right.”
“But if the air changed, why didn’t we change with it? We evolved to be able to breathe a certain kind of air. Shouldn’t the evolution have been cancelled too? For that matter, why do we remember?”
“I don’t know. There’s a lot we don’t know about time travel.”
“I’m not nagging, Svetz. I don’t know either.”
More silence.
“It’s clear enough,” Zeera said presently. “I’ll have to go back and warn myself to get the duplicator on straight.”
“That won’t work. It didn’t work. If you’d gotten the ends of the duplicator on straight we wouldn’t be in this mess. Therefore you didn’t.”
“Logic and time travel don’t go, remember?”
“Maybe we can go around you.” Svetz hesitated, then plunged in. “Try this. Send me back to an hour before the earlier Zeera arrives. The automobile won’t have disappeared yet. I’ll duplicate it, duplicate the duplicate, take the reversed duplicate and the original past you in the big extension cage. That leaves you to destroy the duplicate. I reappear after you’re gone, leave the original automobile for Ford, and come back here with the reverse duplicate. How’s that?”
“It sounded great. Would you mind going through it again?”
“Let’s see. I go back to—”
She was laughing at him. “Never mind. But it has to be me, Svetz. You couldn’t find your way. You couldn’t ask directions or read the street signs. You’ll have to stay here and man the machinery.”
* * *
Svetz was crawling out of the extension cage when there came a scream like the end of the world.
Momentarily he froze. Then he dashed around the swelling flank of the cage. Zeera followed, wearing the filter helmet she had worn during her attempt to duplicate Ford’s automobile.
One wall of the Center was glass. It framed a crest of hill across from the Palace, and a double row of cages that made up the Zoo. One of the cages was breaking apart as they watched, smashing itself to pieces like—
—Like an egg hatching. And like a chick emerging, the roc stood up in the ruin of its cage.
The scream came again.
“What is it?” Zeera whispered.
“It was an ostrich. I’d hate to give it a name now.”
The bird seemed to move in slow motion. There was so much of it! Green and black, beautiful and evil, big as eternity, and a crest of golden feathers had sprouted on its forehead. Its hooked beak descended toward a cage.
That cage ripped like tissue paper.
Zeera was shaking his arm. “Come on! If it came from the Zoo, we don’t need to worry about it. It’ll suffocate when we get the car back where it belongs.”
“Oh. Right,” said Svetz. They went to work moving the big extension cage a few hours further back in time.
When Svetz looked again, the bird was just taking to the air. Its wings flapped like sails, and their black shadows swept like clouds over the houses. As the roc rose fully into view, Svetz saw that something writhed and struggled in its tremendous talons.
Svetz recognized it … and realized just how big the roc really was.
“It’s got Elephant,” he said. An inexplicable sorrow gripped his heart. Inexplicable, for Svetz hated animals.
“What? Come on, Svetz!”
“Um? Oh, yes.” He helped Zeera into the small extension cage and sent it on its way.
Despite its sleeping crew, the machinery of the Center was working perfectly. If anything got off, Svetz would have six men’s work to do. Therefore he prowled among the control boards, alert for any discrepancy, making minor adjustments … And occasionally he looked out the picture window.
The roc had reached an enormous height. Any other bird would have been invisible long since. But the roc was all too apparent, hovering in the blue alien sky while it killed and ate Elephant.
Bloody bones fell in the walkway.
Time passed.
Twenty minutes for Zeera to get back.
More time to make two duplicates of the automobile. Load them into the big extension cage. Then to signal Svetz—
The signal came. She had the cars. Svetz played it safe, moved her forward six hours, almost to dawn on the crucial night. She might be caught by an early riser, but at least Ford would have his automobile back.
The roc had finished its bloody meal. Elephant was gone. And—Svetz watched until he was sure—the bird was dropping, riding down the sky on outstretched wings.
Svetz watched it grow bigger, and bigger yet, until it seemed to enfold the universe. It settled over the Center like a tornado cloud, in darkness, and wind. Like twin tornado funnels, two sets of curved talons touched down in the walkway.
The bird bent low. An inhuman face looked in at Svetz through the picture window. It nearly filled the window.
It knows me, Svetz thought. Even a bird’s brain must be intelligent in a head that size.
The vast head rose out of sight above the roof.
I had the ostrich. I should have been satisfied, thought Svetz. A coin in the hand is worth two in the street. The ancient proverb could as easily be applied to birds.
The roof exploded downward around a tremendous hooked beak. Particles of concrete spattered against walls and floor. A yellow eye rolled and found Svetz, but the beak couldn’t reach him. Not through that hole.
The head withdrew through the roof.
Three red lights. Svetz leapt for the board and began twisting dials. He made two lights turn green, then the third. It had not occurred to him to run. The bird would find him out wherever he hid …
There! Zeera had pulled the go-home lever. From here it was all automatic.
Crash!
Svetz was backed up against the big time machine, pinned by a yellow eye as big as himself. Half the roof was gone now. Still the curved beak couldn’t reach him. But a great claw came seeking him through the shattered glass.
The light changed.
Svetz sagged. Behind the green and black feathers he could see that the sky had turned pale yellow-green, marked with yellow-brown streamers of cloud.
The bird sniffed incredulously, once, twice. Somehow the panic showed in its tremendous eye, before the great head rose through the roof. The roc stepped back from the Center for clearance; its dark wings swept down like night falling.
Svetz was beyond fear or common sense. He stepped out to watch it rise.
He had to hug an ornamental pillar. The wind of the wings was a hurricane. The bird looked down once, recognized him, and looked away.
It was still well in view, rising and circling, when Zeera stepped out to join him. Presently Ra Chen was there to follow their eyes. Then half the Center maintenance team was gaping up in awe and astonishment.
The bird dwindled to a black shadow. Black against pastel green, climbing, climbing.
Suffocating.
One sniff had been enough. The bird’s brain was as enormously proportioned as the rest of it. It had started climbing immediately, without waiting to snatch up Svetz for its dessert.
Climbing, climbing toward the edge of space. Reaching for clean air.
The Secretary-General stood beside Svetz, smiling in wonder, chuckling happily as he gazed upward.
Was the roc still climbing? No, the black shadow was growing larger, sliding down the sky. And the slow motion of the wings had stopped.
How was a roc to know that there was no clean air anywhere?
THERE’S A WOLF IN MY TIME MACHINE
The old extension cage had no fine controls; but that hardly mattered. It wasn’t as if Svetz were chasing some particular extinct animal. Ra Chen had told him to take whatever came to hand.
Svetz guided the cage back to pre-Industrial America, somewhere in mid-continent, around 1000 Ante Atomic Era. Few humans, many animals. Perhaps he’d find a bison.
And when he pulled himself to the windo
w, he looked out upon a vast white land.
Svetz had not planned to arrive in mid-winter.
Briefly he considered moving into the time stream again and using the interrupter circuit. Try another date, try his luck again. But the interrupter circuit was new, untried, and Svetz wasn’t about to be the first man to test it.
Besides which, a trip into the past cost over a million commercials. Using the interrupter circuit would nearly double that. Ra Chen would be displeased.
Svetz began freezing to death the moment he opened the door. From the doorway the view was all white, with one white bounding shape far away.
Svetz shot it with a crystal of soluble anaesthetic.
He used the flight stick to reach the spot. Now that it was no longer moving, the beast was hard to find. It was just the color of the snow, but for its open red mouth and the black pads on its feet. Svetz tentatively identified it as an arctic wolf.
It would fit the Vivarium well enough. Svetz would have settled for anything that would let him leave this frozen wilderness. He felt uncommonly pleased with himself. A quick, easy mission.
Inside the cage, he rolled the sleeping beast into what might have been a clear plastic bag, and sealed it. He strapped the wolf against one curved wall of the extension cage. He relaxed into the curve of the opposite wall as the cage surged in a direction vertical to all directions.
Gravity shifted oddly.
A transparent sac covered Svetz’s own head. Its lip was fixed to the skin of his neck. Now Svetz pulled it loose and dropped it. The air system was on; he would not need the filter sac.
The wolf would. It could not breathe Industrial Age air. Without the filter sac to remove the poisons, the wolf would choke to death. Wolves were extinct in Svetz’s time.
Outside, time passed at a furious rate. Inside, time crawled. Nestled in the sphericalcurve of the extension cage, Svetz stared up at the wolf, who now seemed fitted into the curve of the ceiling.
Svetz had never met a wolf in the flesh. He had seen pictures in children’s books … and even the children’s books had been stolen from the deep past. Why should the wolf look so familiar?
It was a big beast, possibly as big as Hanville Svetz, who was a slender, small-boned man. Its sides heaved with its panting. Its tongue was long and red and its teeth were white and sharp.
Like the dogs, Svetz remembered. The dogs in the Vivarium, in the glass case labeled:
DOG CONTEMPORARY
Alone of the beasts in the Vivarium, the dogs were not sealed in glass for their own protection. The others could not breathe the air outside. The dogs could.
In a very real sense, they were the work of one man. Lawrence Wash Porter had lived near the end of the Industrial Period, between 50 and 100 Post Atomic Era, when billions of human beings were dying of lung diseases while scant millions adapted. Porter had decided to save the dogs.
Why the dogs? His motives were obscure, but his methods smacked of genius. He had acquired members of each of the breeds of dog in the world, and bred them together, over many generations of dogs and most of his own lifetime.
There would never be another dog show. Not a purebred dog was left in the world. But hybrid vigor had produced a new breed. These, the ultimate mongrels, could breathe Industrial Age air, rich in oxides of carbon and nitrogen, scented with raw gasoline and sulfuric acid.
The dogs were behind glass because people were afraid of them. Too many species had died. The people of 1100 Post Atomic were not used to animals.
Wolves and dogs … could one have sired the other?
Svetz looked up at the sleeping wolf and wondered. He was both like and unlike the dogs. Dogs grinned out through the glass and wagged their tails when children waved. Dogs liked people. But the wolf, even in sleep …
Svetz shuddered. Of all the things he hated about his profession, this was the worst: the ride home, staring up at a strange and dangerous extinct animal. The first time he’d done it, a captured horse had seriously damaged the control panel. On his last mission an ostrich had kicked him and broken three ribs.
The wolf was stirring restlessly … and something about it had changed.
Something was changing now. The beast’s snout was shorter, wasn’t it? Its forelegs lengthened peculiarly; its paws seemed to grow and spread. Svetz caught his breath.
Svetz caught his breath, and instantly forgot the wolf. Svetz was choking, dying. He snatched up his filter sac and threw himself at the controls.
* * *
Svetz stumbled out of the extension cage, took three steps and collapsed. Behind him, invisible contaminants poured into the open air.
The sun was setting in banks of orange cloud.
Svetz lay where he had fallen, retching, fighting for air. There was an outdoor carpet beneath him, green and damp, smelling of plants. Svetz did not recognize the smell, did not at once realize that the carpet was alive. He would not have cared at that point. He knew only that the cage’s air system had tried to kill him. The way he felt, it had probably succeeded.
It had been a near thing. He had been passing 30 Post Atomic when the air went bad. He remembered clutching the interrupter switch, then waiting, waiting. The foul air stank in his nostrils and caught in his throat and tore at his larynx. He had waited through twenty years, feeling every second of them. At 50 Post Atomic he had pulled the interrupter switch and run choking from the cage.
50 PA. At least he had reached industrial times. He could breathe the air.
It was the horse, he thought without surprise. The horse had pushed its wickedly pointed horn through Svetz’s control panel, three years ago. Maintenance was supposed to fix it. They had fixed it.
Something must have worn through.
The way he looked at me every time I passed his cage. I always knew the horse would get me, Svetz thought.
He noticed the filter sac still in his hand. Not that he’d be—
Svetz sat up suddenly.
There was green all about him. The damp green carpet beneath him was alive; it grew from the black ground. A rough, twisted pillar thrust from the ground, branched into an explosion of red and yellow papery things. More of the crumpled colored paper lay about the pillar’s base. Something that was not an aircraft moved erratically overhead, a tiny thing that fluttered and warbled.
Living, all of it. A pre-Industrial wilderness.
Svetz pulled the filter sac over his head and hurriedly smoothed the edges around his neck to form a seal. Blind luck that he hadn’t fainted yet. He waited for it to puff up around his head. A selectively permeable membrane, it would pass the right gasses in and out until the composition of the air was—was—
Svetz was choking, tearing at the sac.
He wadded it up and threw it, sobbing. First the air plant, now the filter sac! Had someone wrecked them both? The inertial calender too; he was at least a hundred years previous to 50 Post Atomic.
Someone had tried to kill him.
Svetz looked wildly about him. Uphill across a wide green carpet, he saw an angular vertical-sided formation painted in shades of faded green. It had to be artificial. There might be people there. He could—
No, he couldn’t ask for help either. Who would believe him? How could they help him anyway? His only hope was the extension cage. And his time must be very short.
The extension cage rested a few yards away, the door a black circle on one curved side. The other side seemed to fade away into nothing. It was still attached to the rest of the time machine, in 1103 PA, along a direction eyes could not follow.
Svetz hesitated near the door. His only hope was to disable the air plant somehow. Hold his breath, then—
The smell of contaminants was gone.
Svetz sniffed at the air. Yes, gone. The air plant had exhausted itself, drained its contaminants into the open air. No need to wreck it now. Svetz was sick with relief.
He climbed in.
He remembered the wolf when he saw the filter sac, torn and empty. Th
en he saw the intruder towering over him, the coarse thick hair, the yellow eyes glaring, the taloned hands spread wide to kill.
* * *
The land was dark. In the east a few stars showed, though the west was still deep red. Perfumes tinged the air. A full moon was rising.
Svetz staggered uphill, bleeding.
The house on the hill was big and old. Big as a city block, and two floors high. It sprawled out in all directions, as though a mad architect had built to a whim that changed moment by moment. There were wrought iron railings on the upper windows, and wrought iron handles on the screens on both floors, all painted the same dusty shade of green. The screens were wood, painted a different shade of green. They were closed across every window. No light leaked through anywhere.
The door was built for someone twelve feet tall. The knob was huge. Svetz used both hands and put all his weight into it, and still would not turn. He moaned. He looked for the lens of a peeper camera and could not find it. How would anyone know he was here? He couldn’t find a doorbell either.
Perhaps there was nobody inside. No telling what this building was. It was far too big to be a family dwelling, too spread out to be a hotel or apartment house. Might it be a warehouse or a factory? Making or storing what?
Svetz looked back toward the extension cage. Dimly he caught the glow of the interior lights. He also saw something moving on the living green that carpeted the hill.
Pale forms, more than one.
Moving this way?
Svetz pounded on the door with his fists. Nothing. He noticed a golden metal thing, very ornate, high on the door. He touched it, pulled at it, let it go. It clanked.
He took it in both hands and slammed the knob against its base again and again. Rhythmic clanking sounds. Someone should hear it.
Something zipped past his ear and hit the door hard. Svetz spun around, eyes wild, and dodged a rock the size of his fist. The white shapes were nearer now. Bipeds, walking hunched.
They looked too human—or not human enough.
The door opened.
She was young, perhaps sixteen. Her skin was very pale, and her hair and brows were pure white, quite beautiful. Her garment covered her from neck to ankles, but left her arms bare. She seemed sleepy and angry as she pulled the door open—manually, and it was heavy, too. Then she saw Svetz.