The first of the exploring bugs reached the line of ore carts. It veered slightly and continued its search; the carts traveled in their inexorable line as if nothing had happened.
Disappointed, Morrison turned away from the window and swore. "No use. It's like each doesn't exist for the other."
Gradually the exploring crew moved away from the line of carts, past the mining operations and over a ridge beyond. There was no special hurry; they departed without having reacted to the ore-gathering syndrome.
"Maybe they're from the same factory," Morrison said hopefully.
O'Neill pointed to the antennas visible on the major mining equipment. "Their vanes are turned at a different vector, so these represent two factories. It's going to be hard; we'll have to get it exactly right or there won't be any reaction." He clicked on the radio and got hold of the monitor at the settlement. "Any results on the consolidated back-order sheets?"
The operator put him through to the settlement governing offices.
"They're starting to come in," Ferine told him. "As soon as we get sufficient samplings, we'll try to determine which raw materials which factories lack. It's going to be risky, trying to extrapolate from complex products. There may be a number of basic elements common to the various sublets."
"What happens when we've identified the missing element?" Morrison asked O'Neill. "What happens when we've got two tangent factories short on the same material?"
"Then," O'Neill said grimly, "we start collecting the material ourselves — even if we have to melt down every object in the settlements."
III
In the moth-ridden darkness of night, a dim wind stirred, chill and faint. Dense underbrush rattled metallically. Here and there a nocturnal rodent prowled, its senses hyper-alert, peering, planning, seeking food.
The area was wild. No human settlements existed for miles; the entire region had been seared flat, cauterized by repeated H-bomb blasts. Somewhere in the murky darkness, a sluggish trickle of water made its way among autofac slag and weeds, dripping thickly into what had once been an elaborate labyrinth of sewer mains. The pipes lay cracked and broken, jutting up into the night darkness, overgrown with creeping vegetation. The wind raised clouds of black ash that swirled and danced among the weeds. Once an enormous mutant wren stirred sleepily, pulled its crude protective night coat of rags around it and dozed off.
For a time, there was no movement. A streak of stars showed in the sky overhead, glowing starkly, remotely. Earl Ferine shivered, peered up and huddled closer to the pulsing heat-element placed on the ground between the three men.
"Well?" Morrison challenged, teeth chattering.
O'Neill didn't answer. He finished his cigarette, crushed it against a mound of decaying slag and, getting out his lighter, lit another. The mass of tungsten — the bait — lay a hundred yards directly ahead of them.
During the last few days, both the Detroit and Pittsburgh factories had run short of tungsten. And in at least one sector, their apparatus overlapped. This sluggish heap represented precision cutting tools, parts ripped from electrical switches, high-quality surgical equipment, sections of permanent magnets, measuring devices — tungsten from every possible source, gathered feverishly from all the settlements.
Dark mist lay spread over the tungsten mound. Occasionally, a night moth fluttered down, attracted by the glow of reflected starlight. The moth hung momentarily, beat its elongated wings futilely against the interwoven tangle of metal and then drifted off, into the shadows of the thick-packed vines that rose up from the stumps of sewer pipes.
"Not a very damn pretty spot," Ferine said wryly.
"Don't kid yourself," O'Neill retorted. "This is the prettiest spot on Earth. This is the spot that marks the grave of the autofac network. People are going to come around here looking for it someday. There's going to be a plaque here a mile high."
"You're trying to keep your morale up," Morrison snorted. "You don't believe they're going to slaughter themselves over a heap of surgical tools and light-bulb filaments. They've probably got a machine down in the bottom level that sucks tungsten out of rock."
"Maybe," O'Neill said, slapping at a mosquito. The insect dodged cannily and then buzzed over to annoy Ferine. Ferine swung viciously at it and squatted sullenly down against the damp vegetation.
And there was what they had come to see.
O'Neill realized with a start that he had been looking at it for several minutes without recognizing it. The search-bug lay absolutely still. It rested at the crest of a small rise of slag, its anterior end slightly raised, receptors fully extended. It might have been an abandoned hulk; there was no activity of any kind, no sign of life or consciousness. The search-bug fitted perfectly into the wasted, fire-drenched landscape. A vague tub of metal sheets and gears and flat treads, it rested and waited. And watched.
It was examining the heap of tungsten. The bait had drawn its first bite.
"Fish," Ferine said thickly. "The line moved. I think the sinker dropped."
"What the hell are you mumbling about?" Morrison grunted. And then he, too, saw the search-bug. "Jesus," he whispered. He half rose to his feet, massive body arched forward. "Well, there's one of them. Now all we need is a unit from the other factory. Which do you suppose it is?"
O'Neill located the communication vane and traced its angle. "Pittsburgh, so pray for Detroit… pray like mad."
Satisfied, the search-bug detached itself and rolled forward. Cautiously approaching the mound, it began a series of intricate maneuvers, rolling first one way and then another. The three watching men were mystified — until they glimpsed the first probing stalks of other search-bugs.
"Communication," O'Neill said softly. "Like bees."
Now five Pittsburgh search-bugs were approaching the mound of tungsten products. Receptors waving excitedly, they increased their pace, scurrying in a sudden burst of discovery up the side of the mound to the top. A bug burrowed and rapidly disappeared; The whole mound shuddered; the bug was down inside, exploring the extent of the find.
Ten minutes later, the first Pittsburgh ore carts appeared and began industriously hurrying off with their haul.
"Damn it!" O'Neill said, agonized. "They'll have it all before Detroit shows up."
"Can't we do anything to slow them down?" Ferine demanded helplessly. Leaping to his feet, he grabbed up a rock and heaved it at the nearest cart. The rock bounced off and the cart continued its work, unperturbed.
O'Neill got to his feet and prowled around, body rigid with impotent fury. Where were they? The autofacs were equal in all respects and the spot was the exact same linear distance from each center. Theoretically, the parties should have arrived simultaneously. Yet there was no sign of Detroit — and the final pieces of tungsten were being loaded before his eyes.
But then something streaked past him.
He didn't recognize it, for the object moved too quickly. It shot like a bullet among the tangled vines, raced up the side of the hill-crest, poised for an instant to aim itself and hurtled down the far side. It smashed directly into the lead cart. Projectile and victim shattered in an abrupt burst of sound.
Morrison leaped up. "What the hell?"
"That's it!" Ferine screamed, dancing around and waving his skinny arms. "It's Detroit!"
A second Detroit search-bug appeared, hesitated as it took in the situation, and then flung itself furiously at the retreating Pittsburgh carts. Fragments of tungsten scattered everywhere — parts, wiring, broken plates, gears and springs and bolts of the two antagonists flew in all directions. The remaining carts wheeled screechingly; one of them dumped its load and rattled off at top speed. A second followed, still weighed down with tungsten. A Detroit search-bug caught up with it, spun directly in its path and neatly overturned it. Bug and cart rolled down a shallow trench, into a stagnant pool of water. Dripping and glistening, the two of them struggled, half submerged.