«What in the devil is this?» It was almost a snarl from Hull.
«I—don’t—know. There seems to be some kind of resistance which increases the further back we try to go—»
«Come on!»
«But—»
«Come on, God damn it!»
Saunders shrugged hopelessly.
It took two hours to fight back five years. Then Saunders stopped the projector. His voice shook.
«No go, Sam. We’ve used up three quarters of our stored energy—and the farther back we go, the more we use per year. It seems to be some sort of high-order exponential function.»
«So—»
«So we’d never make it. At this rate, our batteries will be dead before we get back another ten years.» Saunders looked ill. «It’s some effect the theory didn’t allow for, some accelerating increase in power requirements the farther back into the past we go. For twenty-year hops or less, the energy increases roughly as the square of the number of years traversed. But it must actually be something like an exponential curve, which starts building up fast and furious beyond a certain point. We haven’t enough power left in the batteries!»
«If we could recharge them—»
«We don’t have such equipment with us. But maybe—»
They climbed out of the ruined basement and looked eagerly towards the river. There was no sign of the village. It must have been torn down or otherwise destroyed still further back in the past at a point they’d been through.
«No help there,» said Saunders.
«We can look for a place. There must be people somewhere!»
«No doubt.» Saunders fought for calm. «But we could spend a long time looking for them, you know. And—» His voice wavered. «Sam, I’m not sure even recharging at intervals would help. It looks very much to me as if the curve of energy consumption is approaching a vertical asymptote.»
«Talk English, will you?» Hull’s grin was forced.
«I mean that beyond a certain number of years an infinite amount of energy may be required. Like the Einsteinian concept of light as the limiting velocity. As you approach the speed of light, the energy needed to accelerate increases ever more rapidly. You’d need infinite energy to get beyond the speed of light—which is just a fancy way of saying you can’t do it. The same thing may apply to time as well as space.»
«You mean—we can’t ever get back?»
«I don’t know.» Saunders looked desolately around at the smiling landscape. «I could be wrong. But I’m horribly afraid I’m right.»
Hull swore. «What’re we going to do about it?»
«We’ve got two choices,» Saunders said. «One, we can hunt for people, recharge our batteries, and keep trying. Two, we can go into the future.»
«The future!»
«Uh-huh. Sometime in the future, they ought to know more about such things than we do. They may know a way to get around this effect. Certainly they could give us a powerful enough engine so that, if energy is all that’s needed, we can get back. A small atomic generator, for instance.»
Hull stood with bent head, turning the thought over in his mind. There was a meadowlark singing, somewhere, maddeningly sweet.
Saunders forced a harsh laugh. «But the very first thing on the agenda,» he said, «is breakfast.»
Chapter 2
Belgotai of Syrtis
The food was tasteless. They ate in a heavy silence, choking the stuff down. But in the end they looked at each other with a common resolution.
Hull grinned and stuck out a hairy paw. «It’s a hell of a roundabout way to get home,» he said, «but I’m for it.»
Saunders clasped hands with him, wordlessly. They went back to the machine.
«And now where?» asked the mechanic.
«It’s two thousand eight,» said Saunders.
«How about—well—two thousand five hundred A.D.?»
«Okay. It’s a nice round number. Anchors aweigh!»
The machine thrummed and shook. Saunders was gratified to notice the small power consumption as the years and decades fled by. At that rate, they had energy enough to travel to the end of the world.
Eve, Eve, I’ll come back. I’ll come back if I have to go ahead to Judgment Day…
2500 A.D. The machine blinked into materialization on top of a low hill—the pit had filled in during the intervening centuries. Pale, hurried sunlight flashed through wind-driven rain clouds into the hot interior.
«Come,» said Hull. «We haven’t got all day.»
He picked up the automatic rifle.
«What’s the idea?» exclaimed Saunders.
«Eve was right the first time,» said Hull grimly. «Buckle on that pistol, Mart.»
Saunders strapped the heavy weapon to his thigh. The metal was cold under his fingers.
They stepped out and swept the horizon.
Hull’s voice rose in a shout of glee. «People!»
There was a small town beyond the river, near the site of old Hudson. Beyond it lay fields of ripening grain and clumps of trees. There was no sign of a highway. Maybe surface transportation was obsolete now.
The town looked—odd. It must have been there a long time, the houses were weathered. They were tall peak-roofed buildings, crowding narrow streets. A flashing metal tower reared some five hundred feet into the lowering sky, near the center of town.
Somehow, it didn’t look the way Saunders had visualized communities of the future. It had an oddly stunted appearance, despite the high buildings and—sinister? He couldn’t say. Maybe it was only his depression.
Something rose from the center of the town, a black ovoid that whipped into the sky and lined out across the river. Reception committee, thought Saunders. His hand fell on his pistol butt.
It was an airjet, he saw as it neared, an egg-shaped machine with stubby wings and a flaring tail. It was flying slowly now, gliding groundward toward them.
«Hallo, there!» bawled Hull. He stood erect with the savage wind tossing his flame-red hair, waving. «Hallo, people!»
The machine dove at them. Something stabbed from its nose, a line of smoke—tracers!
Conditioned reflex flung Saunders to the ground. The bullets whined over his head, exploding with a vicious crash behind him. He saw Hull blown apart.
The jet rushed overhead and banked for another assault. Saunders got up and ran, crouching low, weaving back and forth. The line of bullets spanged past him again, throwing up gouts of dirt where they hit. He threw himself down again.
Another try… Saunders was knocked off his feet by the bursting of a shell. He rolled over and hugged the ground, hoping the grass would hide him. Dimly, he thought that the jet was too fast for strafing a single man; it overshot its mark.
He heard it whine overhead, without daring to look up. It circled vulture-like, seeking him. He had time for a rising tide of bitter hate.
Sam—they’d killed him, shot him without provocation—Sam, red-haired Sam with his laughter and his comradeship, Sam was dead and they had killed him.
He risked turning over. The jet was settling to earth; they’d hunt him from the ground. He got up and ran again.
A shot wailed past his ear. He spun around the pistol in his hand, and snapped a return shot. There were men in black uniforms coming out of the jet. It was long range, but his gun was a heavy war model; it carried. He fired again and felt a savage joy at seeing one of the black-clad figures spin on its heels and lurch to the ground.
The time machine lay before him. No time for heroics; he had to get away—fast! Bullets were singing around him.
He burst through the door and slammed it shut. A slug whanged through the metal wall. Thank God the tubes were still warm!