the light here and there, trying to locate undestroyed sections, portions of the assembly process still intact.
It was Morrison who felt it first. He suddenly dropped to his hands and knees; heavy body pressed against the floor, he lay listening, face hard, eyes wide. 'For God's sake—'
'What is it?' O'Neill cried. Then he, too, felt it. Beneath them, a faint, insistent vibration hummed through the floor, a steady hum of activity. They had been wrong; the hawk had not been totally successful. Below, in a deeper level, the factory was still alive. Closed, limited operations still went on.
'On its own,' O'Neill muttered, searching for an extension of the descent lift. 'Autonomous activity, set to continue after the rest is gone. How do we get down?'
The descent lift was broken off, sealed by a thick section of metal. The still-living layer beneath their feet was completely cut off; there was no entrance.
Racing back the way they had come, O'Neill reached the surface and hailed the first truck. 'Where the hell's the torch? Give it here!'
The precious blowtorch was passed to him and he hurried back, puffing, into the depths of the ruined factory where Morrison waited. Together, the two of them began frantically cutting through the warped metal flooring, burning apart the sealed layers of protective mesh.
'It's coming,' Morrison gasped, squinting in the glare of the torch. The plate fell with a clang, disappearing into the level below. A blaze of white light burst up around them and the two men leaped back.
In the sealed chamber, furious activity boomed and echoed, a steady process of moving belts, whirring machine-tools, fast-moving mechanical supervisors. At one end, a steady flow of raw materials entered the line; at the far end, the final product was whipped off, inspected and crammed into a conveyer tube.
All this was visible for a split second; then the intrusion was discovered. Robot relays came into play. The blaze of lights flickered and dimmed. The assembly line froze to a halt, stopped in its furious activity.
The machines clicked off and became silent.
At one end, a mobile unit detached itself and sped up the wall toward the hole O'Neill and Morrison had cut. It slammed an emergency seal in place and expertly welded it tight. The scene below was gone. A moment later the floor shivered as activity resumed.
Morrison, white-faced and shaking, turned to O'Neill. 'What are they doing? What are they making?'
'Not weapons,' O'Neill said.
'That stuff is being sent up' — Morrison gestured convulsively—'to the surface.'
Shakily, O'Neill climbed to his feet. 'Can we locate the spot?'
'I — think so.'
'We better.' O'Neill swept up the flashlight and started toward the ascent ramp. 'We're going to have to see what those pellets are that they're shooting up.'
The exit valve of the conveyor tube was concealed in a tangle of vines and ruins a quarter of a mile beyond the factory. In a slot of rock at the base of the mountains the valve poked up like a nozzle. From ten yards away, it was invisible; the two men were almost on top of it before they noticed it.
Every few moments, a pellet burst from the valve and shot up into the sky. The nozzle revolved and altered its angle of deflection; each pellet was launched in a slightly varied trajectory.
'How far are they going?' Morrison wondered.
'Probably varies. It's distributing them at random.' O'Neill advanced cautiously, but the mechanism took no note of him. Plastered against the towering wall of rock was a crumpled pellet; by accident, the nozzle had released it directly at the mountainside. O'Neill climbed up, got it and jumped down.
The pellet was a smashed container of machinery, tiny metallic elements too minute to be analyzed without a microscope.
'Not a weapon,' O'Neill said.
The cylinder had split. At first he couldn't tell if it had been the impact or deliberate internal mechanisms at work. From the rent, an ooze of metal bits was sliding. Squatting down, O'Neill examined them.
The bits were in motion. Microscopic machinery, smaller than ants, smaller than pins, working energetically, purposefully — constructing something that looked like a tiny rectangle of steel.
'They're building,' O'Neill said, awed. He got up and prowled on. Off to the side, at the far edge of the gully, he came across a downed pellet far advanced on its construction. Apparently it had been released some time ago.
This one had made great enough progress to be identified. Minute as it was, the structure was familiar. The machinery was building a miniature replica of the demolished factory.
'Well,' O'Neill said thoughtfully, 'we're back where we started from. For better or worse.. I don't know.'
'I guess they must be all over Earth by now,' Morrison said, 'landing everywhere and going to work.'
A thought struck O'Neill. 'Maybe some of them are geared to escape velocity. That would be neat — autofac networks throughout the whole universe.'
Behind him, the nozzle continued to spurt out its torrent of metal seeds.
