"I"ll be d.a.m.ned," Lyman growled, shutting off the microfiche record of Garwood"s checking account and calling up the last set of numbers on the computer. "Fifteen thousand dollars. Enough for a year of running if he was careful with it."

Davidson nodded grimly. "And don"t forget the per diem he would have gotten while he was on that seminar tour," he reminded the other. "If he skimped on meals he could have put away another couple of thousand."

Lyman stood up. "I"m going to go talk to the Colonel," he said, moving toward the door. "At least we know now how he"s doing it. We can start hitting all the local landlords again and see which of them has a new tenant who paid in cash."

He left. Great idea, Davidson thought after him. It a.s.sumes, of course, that Garwood didn"t find a sublet that he could get into totally independently of the landlords. In a college town like Champaign that would be easy enough to do.

The financial data was still on the display, and Davidson reached over to cancel it. The screen blanked; and for a long moment he just stared at the flashing cursor. "All right," he said out loud. "But why pick Champaign as a hideout in the first place?"

Because his seminar tour had taken him through there, giving him the chance to rent a safety deposit box?

But the same tour had also taken him to universities in Chicago and Seattle, and either one of those metro areas would have provided him a for bigger haystack to hide in.

So why Champaign?

Garwood was running*that much was clear. But was he running away from something, orrunning toward something? Away from his problems at Backdrop, or towardOr toward a solution to those problems?

His fingers wanted a cigarette. Instead, he reached back to the keyboard. Everything about the Champaign area had, not surprisingly, been loaded into the computer"s main database in the past three weeks. Now if he could just find the right question to ask the machine.

Five minutes later, on his second try, he found it.

There were men, Davidson had long ago learned, who could be put at a psychological disadvantage simply by standing over them while they sat. Colonel Bidwell, clearly, wasn"t one of them. "Yes, I just got finished talking to Major Lyman," he said, looking up at Davidson from behind his desk. "Nice bit of work, if a little late in the day. You here to make sure you get proper credit?"

"No, sir," Davidson said. "I"m here to ask for permission to go back to Champaign to pick up Dr.

Garwood."

Bidwell"s eyebrows raised politely. "Isn"t that a little premature, Major? We haven"t even really gotten a handle on him yet."

"And we may not, either, sir, at least not the way Major Lyman thinks we will. There are at least two ways Garwood could have covered his trail well enough for us not to find it without tipping him off. But I think I know another way to track him down."

"Which is...?"

Davidson hesitated. "I"d like to be there at the arrest, sir."

"You bargaining with me, Major?" Bidwell"s voice remained glacially calm, but there was an unpleasant fire kindling in his eyes.

"No, sir, not really," Davidson said, mentally bracing himself against the force of the other"s will. "But I submit to you that Garwood"s arrest is unfinished business, and that I deserve the chance to rectify my earlier failure."

Bidwell snorted. "As I said when you first came in, Major, you have a bad tendency to get personally involved with your cases."

"And if I"ve really found the way to track Garwood down?"

Bidwell shook his head. "Worth a commendation in my report. Not worth letting you gad about central Illinois."

Davidson took a deep breath. "All right, then, sir, try this: if you don"t let me go get him, someone else will have to do it. Someone who doesn"t already know about the Garwood Effect... but who"ll have to be told."

Bidwell glared up at him, a faintly disgusted expression on his face. Clearly, he was a man who hated being maneuvered... but just as clearly, he was also a man who knew better than to let emotional reactions cloud his logic.And for once, the logic was on Davidson"s side. Eventually, Bidwell gave in.

He stood at the door for a minute, listening. No voices; nothing but the occasional creaking of floorboards. Taking a deep breath, preparing himself for possible action, he knocked.

For a moment there was no answer. Then more creaking, and a set of footsteps approached the door.

"Who is it?" a familiar voice called.

"It"s Major Davidson. Please open the door, Dr. Garwood."

He rather expected Garwood to refuse; but the other was intelligent enough not to bother with useless gestures. There was the click of a lock, the more elongated tinkle of a chain being removed, and the door swung slowly open.

Garwood looked about the same as the last time Davidson had seen him, though perhaps a bit wearier.

Hardly surprising, under the circ.u.mstances. "I"m impressed," he said.

"That I found you?" Davidson shrugged. "Finding people on the run is largely a matter of learning to think the way they do. I seem to have that knack. May I come in?"

Garwood"s lip twisted. "Do I have a choice?" he asked, taking a step backwards.

"Not really." Davidson walked inside, eyes automatically sweeping for possible danger. Across the room a computer terminal was sitting on the floor, humming to itself. "Rented?" he asked, nodding toward it.

"Purchased. They"re not that expensive, really, and renting them usually requires a major credit card and more scrutiny than I could afford. Is that how you traced me?"

"Indirectly. It struck me that this was a pretty unlikely town for someone to try and hide out in... unless there was something here that you needed. The Beckman Inst.i.tute"s fancy computer system was the obvious candidate. Once we had that figured out, all we had to do was backtrack all the incoming modem links. Something of a risk for you, wasn"t it?"

Garwood shook his head. "I didn"t have any choice. I needed the use of a Cray Y-MP, and there aren"t a lot of them around that the average citizen can get access to."

"Besides the ones at Stanford and Minneapolis, that is?"

Garwood grimaced. "I don"t seem to have any secrets left, do I? I"d hoped I"d covered my trail a little better than that."

"Oh, we only got the high points," Davidson a.s.sured him. "And only after the fact. Once we knew you were here for the Beckman supercomputer it was just a matter of checking on which others around the country had had more than their share of breakdowns since you left Backdrop."

Garwood"s lips compressed into a tight line, and something like pain flitted across his eyes. "My fault?"

"I don"t know. Saunders said he"d look into it, see if there might have been other causes. He may have something by the time we get you back."

Garwood snorted. "So Saunders in his infinite wisdom is determined to keep going with it," he said bitterly. "He hasn"t learned anything at all in the past four months, has he?""I guess not." Davidson nodded again at the terminal. "Have you?" he asked pointedly.

Garwood shook his head. "Only that the universe is full of blind alleys."

"Um." Stepping past Garwood, Davidson sat down at the table. "Well, I guess we can make that unanimous," he told the other. "I haven"t learned much lately, either. Certainly not as much as I"d like."

He looked up, to find Garwood frowning at him with surprise. Surprise, and a suddenly nervous indecision... "No, don"t try it, Doctor," Davidson told him. "Running won"t help; I have men covering all the exits. Sit down, please."

Slowly, Garwood stepped forward to sink into the chair across from Davidson. "What do you want?" he asked carefully, resting his hands in front of him on the table.

"I want you to tell me what"s going on," Davidson said bluntly. He glanced down at the table, noting both the equation-filled papers and the loose cigarettes scattered about. "I want to know what Backdrop"s purpose is, why you left it*" he raised his eyes again*"and how this voodoo effect of yours works."

Garwood licked his lips, a quick slash of the tongue tip. "Major... if you had the proper clearance*"

"Then Saunders would have told me everything?" Davidson shrugged. "Maybe. But he"s had three weeks, and I"m not sure he"s ever going to."

"So why should I?"

Davidson let his face harden just a bit. "Because if Backdrop is a danger to my country, I want to know about it."

Garwood matched his gaze for a second, then dropped his eyes to the table, his fingers interlacing themselves into a tight double fist there. Then he took a deep breath. "You don"t play fair, Major," he sighed. "But I suppose it doesn"t really matter anymore. Besides, what"s Saunders going to do?*lock me up? He plans to do that anyway."

"So what is it you know that has them so nervous?" Davidson prompted.

Garwood visibly braced himself. "I know how to make a time machine."

For a long moment the only sound in the room was the hum of the terminal in the corner... and the hazy buzzing of Garwood"s words spinning over and over in Davidson"s brain. "You what?" he whispered at last.

Garwood"s shoulders heaved fractionally. "Sounds impossible, doesn"t it? But it"s true. And it"s because of that..." he broke off, reached over to flick one of the loose cigarettes a few inches further away from him.

"Dr. Garwood*" Davidson licked dry lips, tried again. "Doctor, that doesn"t make any sense.

Why should a... a time machine*?" He faltered, his tongue balking at even suggesting such a ridiculous thing.

"Make things disintegrate?" Garwood sighed. "Saunders didn"t believe it, either, not even after I explainedwhat my paper really said."

The shock was slowly fading from Davidson"s brain. "So what did it say?" he demanded.

"That the uncertainty factor in quantum mechanics didn"t necessarily arise from the observer/universe interaction," Garwood said. "At least not in the usual sense. What I found was a set of self-consistent equations that showed the same effect would arise from the universe allowing for the possibility of time travel."

"And these equations of yours are the ones you recited to me when you wrecked my car and gun?"

Garwood shook his head. "No, those came later. Those were the equations that actually show how time travel is possible." His fingers moved restlessly, worrying at another of the cigarettes. "You know, Major, it would be almost funny if it weren"t so deadly serious. Even after Backdrop started to fall apart around us Saunders refused to admit the possibility that it was our research that was causing it. That trying to build a time travel from my equations was by its very nature a self-defeating exercise."

"A long time ago," Davidson said slowly, "on that car ride from Springfield, you called it subconscious democracy. That cigarettes disintegrated in your hand because some people didn"t like smoking."

Garwood nodded. "It happens to cigarettes, plastics*"

"How? How can peoples" opinions affect the universe that way?"

Garwood sighed. "Look. Quantum mechanics says that everything around us is made up of atoms, each of which is a sort of cloudy particle with a very high mathematical probability of staying where it"s supposed to. In particular, it"s the atom"s electron cloud that shows the most mathematical fuzziness; and it"s the electron clouds that interact with each other to form molecules."

Davidson nodded; that much he remembered from college physics.

"Okay. Now, you told me once that you hated being hooked by cigarettes, right? Suppose you had the chance*right now*to wipe out the tobacco industry and force yourself out of that addiction? Would you do it?"

"With North Carolina"s economy on the line?" Davidson retorted. "Of course not."

Garwood lips compressed. "You"re more ethical than most," he acknowledged. "A lot of the "not-me"

generation wouldn"t even bother to consider that particular consequence. Of course, it"s a moot question anyway*we both know the industry is too well established for anyone to get rid of it now.

"But what if you could wipe it out in, say, 1750?"

Davidson opened his mouth... closed it again. Slowly, it was starting to become clear... "All right," he said at last. "Let"s say I"d like to do that. What then?"

Garwood picked up one of the cigarettes. "Remember what I said about atoms*the atoms in this cigarette are only probably there. Think of it as a given atom being in its proper place ninety-nine point nine nine nine nine percent of the time and somewhere else the rest of it. Of course, it"s never gone long enough to really affect the atomic bonds, which is why the whole cigarette normally holds together.

"But now I know how to make a time machine; and you want to eliminate the tobacco industry in 1750.

If I build my machine, and if you get hold of it, and if you succeed in stamping out smoking, then this cigarette would never have been made and all of its atoms would be somewhere else."Davidson"s mouth seemed abnormally dry. "That"s a lot of ifs," he managed.

"True, and that"s probably why the cigarette doesn"t simply disappear. But if enough of the electron clouds are affected*if they start being gone long enough to strain their bonds with the other atoms*then eventually the cigarette will fall apart." He held out his palm toward Davidson.

Davidson looked at the cigarette, kept his hands where they were. "I"ve seen the demo before, thanks."

Garwood nodded soberly. "It"s scary, isn"t it?"

"Yeah," Davidson admitted. "And all because I don"t like smoking?"

"Oh, it"s not just you," Garwood sighed. He turned his hand over, dropping the cigarette onto the table, where it burst into a little puddle of powder. "You could be president of Philip Morris and the same thing would happen. Remember that if a time machine is built from my equations, literally everyone from now until the end of time has access to the 1750 tobacco crop. And to the start of the computer age; and the inception of the credit card; and the invention of plastic." He rubbed his forehead wearily. "This list goes on and on. Maybe forever."

Davidson nodded, his stomach feeling strangely hollow. A walking time bomb, he"d called Garwood. A time bomb. No wonder everyone at Backdrop had been so quick to latch onto that particular epithet.

"What about my car?" he asked. "Surely no one seriously wants to go back to the horse and buggy."

"Probably not," Garwood shook his head. "But the internal combustion engine is both more complicated and less efficient than several alternatives that were stamped out early in the century. If you could go back and nurture the steam engine, for instance*"

"Which is why the engine seemed to be trying to flow into a new shape, instead of just falling apart?"

Davidson frowned. "It was starting to change into a steam engine?"

Garwood shrugged. "Possibly. I really don"t know for sure why engines behave the way they do."

Almost unwillingly, Davidson reached out to touch what was left of the cigarette. "Why you?" he asked.

"If your time machine is built, then everything in the world ought to be equally fair game. So why don"t things disintegrate in my hands, too?"

"Again, I don"t know for sure. I suspect the probability shifts cl.u.s.ter around me because I"m the only one who knows how to make the machine." Garwood seemed to brace himself. "But you"re right. If the machine is actually made, then it"s all out of my hands... and I can"t see any reason why the effect wouldn"t then mushroom into something worldwide."

A brief mental image flashed through Davidson"s mind: a black vision of the whole of advanced technology falling to pieces, rapidly followed by society itself. If a superpower war of suspicion didn"t end things even quicker... "My G.o.d," he murmured. "You can"t let that happen, Doctor."

Garwood locked eyes with him. "I agree. At the moment, though, you have more power over that than I do."

For a long minute Davidson returned the other"s gaze, torn by indecision. He could do it*he could simply let Garwood walk. It would mean his career, possibly, but the stakes here made such considerations trivial. Another possibility occurred briefly to him... "Why did you need the computer?" he asked Garwood. "What were you trying to do?"

"Find a solution to my equations that would allow for a safer form of time travel," Garwood said."Something that would allow us to observe events, perhaps, without interacting with them."

"Did you have any luck?"

"No. But I"m not ready to give up the search, either. If you let me go, I"ll keep at it."

Davidson clenched his jaw tightly enough to hurt. "I know that, Doctor," he said quietly. "But you"ll have to continue your search at Backdrop."