“I don't know,” I confessed. “I'm just thrashing around.”

  “Well, you'll probably get it more accurately from the UN files. Edward Sinclair did some mathematics on the fields that scoop up interstellar hydrogen for the cargo ramrobots. He was a shoo-in for the exemption. That's the surest way of getting it: make a breakthrough in anything that has anything to do with the interstellar colonies. Every time you move one man away from Earth, the population drops by one.”

  “What was wrong with it?”

  “Nothing anyone could prove. Remember, the Fertility Restriction Laws were new then. They couldn't stand a real test. But Edward Sinclair's a pure math man. He works with number theory, not practical applications. I've seen Edward's equations, and they're closer to something Ray would come up with. And Ray didn't need the exemption. He never wanted children.”

  “So you think—”

  “I don't care which of them redesigned the ramscoops. Diddling the Fertility Board like that, that takes brains.” She swallowed the rest of her drink, set the glass down. “Breeding for brains is never a mistake. It's no challenge to the Fertility Board, either. The people who do the damage are the ones who go into hiding when their shots come due, have their babies, then scream to high heaven when the board has to sterilize them. Too many of those and we won't have Fertility Laws anymore. And that—” She didn't have to finish.

  Had Sinclair known that Pauline Urthiel was once Paul?

  She stared. “Now just what the bleep has that got to do with anything?”

  I'd been toying with the idea that Sinclair might have been blackmailing Urthiel with that information. Not for money but for credit in some discovery they'd made together. “Just thrashing around,” I said.

  “Well ... all right. I don't know if Ray knew or not. He never raised the subject, but he never made a pass, either, and he must have researched me before he hired me. And, say, listen: Larry doesn't know. I'd appreciate it if you wouldn't blurt it out.”

  “Okay.”

  “See, he had his children by his first wife. I'm not denying him children ... Maybe he married me because I had a touch of, um, masculine insight. Maybe. But he doesn't know it, and he doesn't want to. I don't know whether he'd laugh it off or kill me.”

  * * * *

  I had Valpredo drop me off at ARM Headquarters.

  This peculiar machine really does bother me, Gil ... Well it should, Julio. The Los Angeles Police were not trained to deal with a mad scientist's nightmare running quietly in the middle of a murder scene.

  Granted that Janice wasn't the type. Not for this murder. But Drew Porter was precisely the type to evolve a perfect murder around Sinclair's generator, purely as an intellectual exercise. He might have guided her through it; he might even have been there and used the elevator before she shut it off. It was the one thing he forgot to tell her: not to shut off the elevator.

  Or: he outlined a perfect murder to her, purely as a puzzle, never dreaming she'd go through with it—badly.

  Or: one of them killed Janice's uncle on impulse. No telling what he'd said that one of them couldn't tolerate. But the machine had been right there in the living room, and Drew had wrapped his big arm around Janice and said, Wait, don't do anything yet; let's think this out...

  Take any of these as the true state of affairs, and a prosecutor could have a hell of a time proving it. He could show that no killer could possibly have left the scene of the crime without Janice Sinclair's help, and therefore ... But what about that glowing thing, that time machine built by the dead man? Could it have freed a killer from an effectively locked room? How could a judge know its power?

  Well, could it?

  Bera might know.

  The machine was running. I caught the faint violet glow as I stepped into the laboratory and a flickering next to it ... and then it was off, and Jackson Bera stood suddenly beside it, grinning, silent, waiting.

  I wasn't about to spoil his fun. I said, “Well? Is it an interstellar drive?”

  “Yes!”

  A warm glow spread through me. I said, “Okay.”

  “It's a low-inertia field,” said Bera. “Things inside lose most of their inertia ... not their mass, just the resistance to movement. Ratio of about five hundred to one. The interface is sharp as a razor. We think there are quantum levels involved.”

  “Uh huh. The field doesn't affect time directly?”

  “No, it ... I shouldn't say that. Who the hell knows what time really is? It affects chemical and nuclear reactions, energy release of all kinds ... but it doesn't affect the speed of light. You know, it's kind of kicky to be measuring the speed of light at 370 miles per second with honest instruments.”

  Dammit. I'd been half hoping it was an FTL drive. I said, “Did you ever find out what was causing that blue glow?”

  Bera laughed at me. “Watch.” He'd rigged a remote switch to turn the machine on. He used it, then struck a match and flipped it toward the blue glow. As it crossed an invisible barrier, the match flared violet-white for something less than an eye blink. I blinked. It had been like a flashbulb going off.

  I said, “Oh, sure. The machinery's warm.”

  “Right. The blue glow is just infrared radiation being boosted to violet when it enters normal time.”

  Bera shouldn't have had to tell me that. Embarrassed, I changed the subject. “But you said it was an interstellar drive.”

  “Yah. It's got drawbacks,” Bera said. “We can't just put a field around a whole starship. The crew would think they'd lowered the speed of light, but so what? A slowboat doesn't get that close to lightspeed anyway. They'd save a little trip time, but they'd have to live through it five hundred times as fast.”

  “How about if you just put the field around your fuel tanks?”

  Bera nodded. “That's what they'll probably do. Leave the motor and the life support system outside. You could carry a god-awful amount of fuel that way ... Well, it's not our department. Someone else'll be designing the starships,” he said a bit wistfully.

  “Have you thought of this thing in relation to robbing banks? Or espionage?”

  “If a gang could afford to build one of these jobs, they wouldn't need to rob banks.” He ruminated. “I hate making anything this big a UN secret. But I guess you're right. The average government could afford a whole stable of the things.”

  “Thus combining James Bond and the Flash.”

  He rapped on the plastic frame. “Want to try it?”

  “Sure,” I said.

  Heart to brain: THUD! What're you doing? You'll get us all killed! I knew we should never have put you in charge of things ... I stepped up to the generator, waited for Bera to scamper beyond range, then pulled the switch.

  Everything turned deep red. Bera became a statue.

  Well, here I was. The second hand on the wall clock had stopped moving. I took two steps forward and rapped with my knuckles. Rapped, hell: it was like rapping on contact cement. The invisible wall was tacky.

  I tried leaning on it for a minute or so. That worked fine until I tried to pull away, and then I knew I'd done something stupid. I was embedded in the interface. It took me another minute to pull loose, and then I went sprawling backward; I'd picked up too much inward velocity, and it all came into the field with me.

  At that, I'd been lucky. If I'd leaned there a little longer, I'd have lost my leverage. I'd have been sinking deeper and deeper into the interface, unable to yell to Bera, building up more and more velocity outside the field.

  I picked myself up and tried something safer. I took out my pen and dropped it. It fell normally: thirty-two feet per second per second, field time. Which scratched one theory as to how the killer had thought he would be leaving.

  I switched the machine off. “Something I'd like to try,” I told Bera. “Can you hang the machine in the air, say by a cable around the frame?”

  “What have you got in mind?”

  “I want to try standing on the bottom of the field
.”

  Bera looked dubious.

  It took us twenty minutes to set it up. Bera took no chances. He lifted the generator about five feet. Since the field seemed to center on that oddly shaped piece of silver, that put the bottom of the field just a foot in the air. We moved a stepladder into range, and I stood on the stepladder and turned on the generator.

  I stepped off.

  Walking down the side of the field was like walking in progressively stickier taffy. When I stood on the bottom, I could just reach the switch.

  My shoes were stuck solid. I could pull my feet out of them, but there was no place to stand except in my own shoes. A minute later my feet were stuck, too: I could pull one loose, but only by fixing the other ever more deeply in the interface. I sank deeper, and all sensation left the soles of my feet. It was scary, though I knew nothing terrible could happen to me. My feet wouldn't die out there; they wouldn't have time.

  But the interface was up to my ankles now, and I started to wonder what kind of velocity they were building up out there. I pushed the switch up. The lights flashed bright, and my feet slapped the floor hard.

  Bera said, “Well? Learn anything?”

  “Yah. I don't want to try a real test: I might wreck the machine.”

  “What kind of real test—?”

  “Dropping it forty stories with the field on. Quit worrying; I'm not going to do it.”

  “Right. You aren't.”

  “You know, this time compression effect would work for more than just spacecraft. After you're on the colony world, you could raise full-grown cattle from frozen fertilized eggs in just a few minutes.”

  “Mmm ... Yah.” The happy smile flashing white against darkness, the infinity look in Bera's eyes ... Bera liked playing with ideas. “Think of one of these mounted on a truck, say on Jinx. You could explore the shoreline regions without ever worrying about the Bandersnatchi attacking. They'd never move fast enough. You could drive across any alien world and catch the whole ecology laid out around you, none of it running from the truck. Predators in midleap, birds in midflight, couples in courtship.”

  “Or larger groups.”

  “I ... think that habit is unique to humans.” He looked at me sideways. “You wouldn't spy on people, would you? Or shouldn't I ask?”

  “That five-hundred-to-one ratio. Is that constant?”

  He came back to here and now. “We don't know. Our theory hasn't caught up to the hardware it's supposed to fit. I wish to hell we had Sinclair's notes.”

  “You were supposed to send a programmer out there.”

  “He came back,” Bera said viciously. “Clayton Wolfe. Clay says the tapes in Sinclair's computer were all wiped before he got there. I don't know whether to believe him or not. Sinclair was a secretive bastard, wasn't he?”

  “Yah. One false move on Clay's part and the computer might have wiped everything. But he says different?”

  “He says the computer was blank, a newborn mind all ready to be taught. Gil, is that possible? Could whoever have killed Sinclair have wiped the tapes?”

  “Sure, why not? What he couldn't have done is left afterward.” I told him a little about the problem. “It's even worse than that, because as Ordaz keeps pointing out, he thought he'd be leaving with the machine. I thought he might have been planning to roll the generator off the roof, step off with it, and float down. But that wouldn't work. Not if it falls five hundred times as fast. He'd have been killed.”

  “Losing the machine maybe saved his life.”

  “But how did he get out?”

  Bera laughed at my frustration. “Couldn't his niece be the one?”

  “Sure, she could have killed her uncle for the money. But I can't see how she'd have a motive to wipe the computer. Unless—”

  “Something?”

  “Maybe. Never mind.” Did Bera ever miss this kind of manhunting? But I wasn't ready to discuss this yet; I didn't know enough. “Tell me more about the machine. Can you vary that five-hundred-to-one ratio?”

  He shrugged. “We tried adding more batteries. We thought it might boost the field strength. We were wrong; it just expanded the boundary a little. And using one less battery turns it off completely. So the ratio seems to be constant, and there do seem to be quantum levels involved. We'll know better when we build another machine.”

  “How so?”

  “Well, there are all kinds of good questions,” Bera said. “What happens when the fields of two generators intersect? They might just add, but maybe not. That quantum effect ... And what happens if the generators are right next to each other, operating in each other's accelerated time? The speed of light could drop to a few feet per second. Throw a punch and your hand gets shorter!”

  “That'd be kicky, all right.”

  “Dangerous, too. Man, we'd better try that one on the moon!”

  “I don't see that.”

  “Look, with one machine going, infrared light comes out violet. If two machines were boosting each other's performance, what kind of radiation would they put out? Anything from X rays to antimatter particles.”

  “An expensive way to build a bomb.”

  “Well, but it's a bomb you can use over and over again.”

  I laughed. “We did find you an expert,” I said. “You may not need Sinclair's tapes. Bernath Peterfi says he was working with Sinclair. He could be lying—more likely he was working for him, under contract—but at least he knows what the machine does.”

  Bera seemed relieved at that. He took down Peterfi's address. I left him there in the laboratory, playing with his new toy.

  * * * *

  The file from the city morgue was sitting on my desk, open, waiting for me since this morning. Two dead ones looked up at me through sockets of blackened bone, but not accusingly. They had patience. They could wait.

  The computer had processed my search pattern. I braced myself with a cup of coffee, then started leafing through the thick stack of printout. When I knew what had burned away two human faces, I'd be close to knowing who. Find the tool, find the killer. And the tool must be unique or close to it.

  Lasers, lasers—more than half the machine's suggestions seemed to be lasers. Incredible the way lasers seemed to breed and mutate throughout human industry. Laser radar. The laser guidance system on a tunneling machine. Some suggestions were obviously unworkable, and one was a lot too workable.

  A standard hunting laser fires in pulses. But it can be jiggered for a much longer pulse or even a continuous burst.

  Set a hunting laser for a long pulse and put a grid over the lens. The mesh has to be optically fine, on the order of angstroms. Now the beam will spread as it leaves the grid. A second of pulse will vaporize the grid, leaving no evidence. The grid would be no bigger than a contact lens; if you didn't trust your aim, you could carry a pocketful of them.

  The grid-equipped laser would be less efficient, as a rifle with a silencer is less efficient. But the grid would make the murder weapon impossible to identify.

  I thought about it and got cold chills. Assassination is already a recognized branch of politics. If this got out— But that was the trouble; someone seemed to have thought of it already. If not, someone would. Someone always did.

  I wrote up a memo for Lucas Garner. I couldn't think of anyone better qualified to deal with this kind of sociological problem.

  Nothing else in the stack of printout caught my eye. Later I'd have to go through it in detail. For now I pushed it aside and punched for messages.

  Bates, the coroner, had finished the autopsies on the two charred corpses. Nothing new. But records had identified the fingerprints. Two missing persons, disappeared six and eight months ago. Ah ha!

  I knew that pattern. I didn't even look at the names; I just skipped on to the gene coding.

  Right. The fingerprints did not match the genes. All twenty fingertips must be transplants. And the man's scalp was a transplant; his own hair had been blond.

  I leaned back in my chair, gazing
fondly down at holograms of charred skulls.

  You evil sons of bitches. Organleggers, both of you. With all that raw material available, most organleggers change their fingerprints constantly—and their retina prints—but we'd never get prints from those charred eyeballs. So, weird weapon or no, they were ARM business. My business.

  And we still didn't know what had killed them, or who.

  It could hardly have been a rival gang. For one thing, there was no competition. There must be plenty of business for every organlegger left alive after the ARM swept through them last year. For another, why had they been dumped on a city slidewalk? Rival organleggers would have taken them apart for their own organ banks. Waste not, want not.

  On that same philosophy, I had something to be deeply involved in when the mother hunt broke. Sinclair's death wasn't ARM business, and his time compression field wasn't in my field. This was both.

  I wondered what end of the business the dead ones had been in. The file gave their estimated ages: forty for the man, forty-three for the woman, give or take three years each. Too old to be raiding the city street for donors. That takes youth and muscle. I billed them as doctors, culturing the transplants and doing the operations, or salespersons, charged with quietly letting prospective clients know where they could get an operation without waiting two years for the public organ banks to come up with material.

  So they'd tried to sell someone a new kidney and had been killed for their impudence. That would make the killer a hero.

  So why hide them for three days, then drag them out onto a city slidewalk in the dead of night?

  Because they'd been killed with a fearsome new weapon?

  I looked at the burned faces and thought: fearsome, right. Whatever did that had to be strictly a murder weapon. As the optical grid over a laser lens would be strictly a murder technique.

  So a secretive scientist and his deformed assistant, fearful of rousing the wrath of the villagers, had dithered over the bodies for three days, then disposed of them in that clumsy fashion because they panicked when the bodies started to smell. Maybe.

  But a prospective client needn't have used his shiny new terror weapon. He had only to call the cops after they were gone. It read better if the killer was a prospective donor; he'd fight with anything he could get his hands on.