sleep fast. I feel as rested after four hours' sleep as I would have after eight.» «That's good, dear,» Jan said. Then he saw the clock and said, «Now why did you go and do that? I told you how it was going to be.» «You needed some rest,» she said. «I'm not a baby. I can work eight hours.» «I don't want you working eight hours,» he yelled. «I'm the captain of this ship, and when I say wake me in four hours that's exactly what I mean.» And then, «No, dammit, we are not having our first fight. I'm just telling you—» He stopped yelling, grinned at her. She came to him and inserted herself into his arms with a contented little sigh. «Thanks, honey,» he said. «I miss you,» she whispered. «Me too.» Twice during his eight hours he went to the bedroom just to look at her and to count his blessings. It was a slow and tedious process. The ship would blink to the limit of its detection equipment's range, Pete would activate the detection units, see quickly that there was nothing within range, not a stray stone, not a ship the size of Rimfire, and then he'd blink again and go through the same thing over again. Days of it, weeks of it, months of it lay ahead of him. One lost an appreciation of the vast distances involved in blink travel until one had to cover the same space in diddly-bopping little hops. During that search of the space between the two beacons Pete got an idea of what life would have been like on an X&A ship assigned to laying down new blink ranges. He told Jan that maybe it was lucky he had a hole in his head so that he wasn't spending his life making short hops, checking detection instruments, waiting for the generator to build. He made no objection when, on her next watch, Jan pulled eight hours. He awakened naturally after a good, solid seven hours of sleep and came into control with a pot of fresh coffee and some of those excellent sweetmeats from Good Haven, a small planet back in the main body of the U.P. whose soil produced the most fantastic fruits and cereals in the entire known galaxy. «Hi,» he said. «Little taste of something?» «Ummm,» she said, reaching for a sweet. It was deliciously gooey and sticky, and she licked her fingers after eating it. He leaned over and kissed her. «You taste good,» he said. «You, too. Sweet.» «I'm always sweet. No action?» He punched the computer and got a quick read of the past seven hours. He wasn't checking up on her. She'd demonstrated that she'd learned well. It was just good policy to double-check. She did the same when she relieved him. «As you see,» she said. «More coffee?» «You're a doll,» she said, holding out her mug. «Ever consider how little important things change?» he mused. «This stuff. Coffee. It goes back into the dim, distant history of man. Back when there was only good, old Earth and it looked as if the race was intent on destroying itself with endless wars. Guys on duty on watercraft drank this stuff from wooden cups, or whatever they had then. I'll bet it tasted just as good then as it does now.» «My friendly philosopher,» Jan said. «Pete—» He looked up at her, lifting his eyes from the cream-whitened coffee. «I was playing around with that tape. The one from NE794?» «Yeah?» «I want you to hear something,» she said. She punched buttons. The brief, ghostly signal came into his ears, and then repeated itself several more times. «You've stretched it out just slightly,» he said. He'd noted the elapsed time on the meter of the communications bank. The original signal, microseconds long, had lasted twice as long. «No,» she said. «What do you mean, no?» «I mean it's not stretched. What you're hearing is the entire signal. Remember that little area which we thought might have been just a manufacturer's defect in the coating, or maybe an emission of some sort of energy which the tape was not designed to record? Well, I was fiddling with things. Frequency-distortion correction and things like that.» «Lord, you didn't mess up the original tape,» he said. «No. I used a duplicate to play with.» «So what did you do?» «I don't know, really. I was just playing with the machine to pass the time while the generator was building charge and I noticed that I could change the characteristic of the sound by making certain adjustments.» He nodded. «Honey, it doesn't mean anything. Actually, the sound we hear on that signal bears no direct relationship to the signal itself. A pre-blink signal is a kind of emission which is unique, and when it was first discovered there were no machines to convert it into something which our senses could detect. It's not sound, of course, nor light, nor anything but what it is. So they just arbitrarily chose to make the signal activate a sound-generating unit so that there'd be some way, other than looking at a sensitive meter, to know that a pre-blink signal was there.» She nibbled at another sweetmeat. «So all I did was just alter the tone of the sound?» «I'm afraid so.» «But that small area on the tape isn't like a regular blink signal. How did it get transcribed into sound waves?» He thought about it and it seemed to go around and around in his head. His fingers went up to toy with the dent in his skull over his ear. Jan was immediately sorry. She hadn't intended to pose a problem which would touch him in what he thought was his weak area. «Well, never mind,» she said. «Look, the generator's been drained. I used all of it in small jumps and now she's building.» She wiped her hands on a napkin, licked her lips, lifted herself from her chair to sit on his lap. «We have at least twenty minutes. Can you think of some way to spend it?» He could. He did. He left her sleeping peacefully and went to the control room. There he checked charge, decided to let the generator continue to build, punched up the tape she'd been playing with. He used the computer to analyze, and there was no difference between the first half of the signal, that ghostly beginning of a pre-blink emission, and the second half, which had been nothing more than a disturbed area on the coating of the tape. He rubbed his dent and tried to reason it out. He ran the problem through the computer and found that the odds against Jan's hitting the exact tone of that sound, starting with what was, in effect, nothing, were astronomical. The generator was on full charge. He started working, making the small leaps until he had the big beast drained down, finding nothing, then it was charge time again and he was back at the console, playing with Jan's tape. He started from the original and began to adjust and tinker with the various sophisticated adjustments which were designed to enhance, refine, delete certain overtones, and he had to get help from the computer to arrive at the same sound Jan had found by accident. But it was there. First of all that disturbed area of tape was converted to a level of sound so low that it had to be amplified thousands of times and then the gadgets began twisting and enhancing and then it was there, not just a ghostly beginning but a good beginning to a pre-blink signal. He pulled a complete pre-blink signal from the 47's permanent tapes and did the same tricks with it. He could alter the tone of it, tune it, at will, once he programmed the process into the computer. But it still meant nothing, for all he was doing was altering the tone of sound. He was not changing the basic pre-blink signal in the slightest, only the byproduct of that signal after the unique emission had been converted into audible waves. He shrugged and put the tapes away and concentrated on the search as the hours crawled by slowly. With two hours to go before he woke Jan he began to think about the tapes again. Pre-blink signals were all the same. There was no such thing as different frequencies. The pre-blink signal had no wavelength. It was different, as different as light from sound. It could not be tuned, or altered, in any way. Could it? He shook his head. At least not by an Academy kick-out with a hole in his head. But there was a thought somewhere, or at least a near thought, which haunted him as he went about the familiar routine of search. He pounded his head with his fist. It was not the first time he had silently cursed his inability to form an elusive thought, to break through the barrier that seemed to block him off from a part of his thinking ability. «Damn, damn, damn,» he muttered. He was slumped in his chair, fingering the dent in his head, when Jan, fresh from sleep, awake a bit early, came in with the coffee. Her heart went out to him as she saw the look of intensity on his face, saw the fingers moving in a little frenzy of motion over the little depression in his skull. She occasionally tired of wearing the simple silken singlet. She'd dressed in a frilly little frock which was suitable for nothing much but entertaining at the Spacer's Rest and for making her husband forget any problems. He broke into a wide smile when he saw her, and then the coffee was good, and the talk good. The dress reminded him of the time when he was talking his head off trying to persuade her to marry him, and he was thinking seriously about letting the damned generator sit on full charge for a while. There were sweeter things to do than search endlessly for a ship that might or might not have been blown to nothing. «I think we deserve a little time off,» he grinned at her. «You're the skipper,» she said. He rose, bent to kiss her. «Race you to the bedroom.» «No fair,» she said. «My legs are shorter than yours.» «I'll give you a head start.» «That sounds fair,» she said, reaching up to kiss him. Oh, God, she was beautiful. She deserved all the best things that the galaxy had to offer her, not the isolation of life on board a Mule. She deserved much more than life had handed her, a tour of duty in a whorehouse, a broken-down tugboat loser. And he had a way to give it to her. All he had to do was find Rimfire. It blazed into his mind like a runaway comet. «The pre-blink signal guides the ship,» he said, straightening suddenly. «That, sir, is an abrupt change of subject,» Jan said. «Jan, that's what it's for. It has to be. All these centuries we've been looking on it as just something which was there, and we've even looked for ways to get rid of it because in times of war an enemy ship could have advance warning because of it. But it has to be there.» «I'm lost,» Jan admitted. «Don't you see?» He bent over her, his hands on the arms of her chair, his face near hers. «Look, we talk about locking onto the next blink beacon, right? It's standard procedure. An officer says, 'Lock onto blink beacon so-and-so.' But there's nothing to lock onto, because a blink beacon doesn't broadcast a signal or anything. It's just there. It has relay and recording equipment. But we 'lock onto' a beacon by inserting a predetermined coordinate into the navigation computer. We can even pick a coordinate at random and leap out into an area where there's no blink beacon, if we want to risk it.» «I agree,» Jan said. «But I don't see where you're going with this.» «We don't know a helluva lot about what goes on when a ship is in subspace.» He fingered his skull. «What if subspace is dimensionless and infinite? Some say it is. We dump a ship into it by the power of a generator. That ship has no motion, Jan. It can be sitting absolutely stationary when a blink begins and it's absolutely stationary when the blink ends. And yet there's movement in subspace, movement of some kind. That ship has to know where to go in subspace in order to emerge at a particular point in real space.» «So?» she asked. «So the pre-blink signal points the way.» He was pacing now, his fingers actually scratching at the dent. «Or maybe the pre-blink is the ship, and it arrives in the subspace form in the form of the pre-blink and—» He halted. «Damn, damn, damn.» She recognized the symptom. He'd come up against a blank wall in his thinking. «You're doing pretty good for a guy with a hole in his head,» she said encouragingly. «Go on.» «It's silly,» he said. «Not at all. You're making sense.» «Yeah, old Peter Jaynes figures out things that the scientists have been working on for centuries.» «Why not?» she asked. «Billy Bob Blink was a TV repairman.» Lord, she had faith in him, and he was stupid, stupid, unable to think. He paced. «The basic design of the blink generator hasn't changed in a thousand years,» he said. He was just blowing smoke. He knew it. He was just acting as if he could think to earn the admiration of the person who was his life. «No reason to change it,» he said. «You can't improve on the perfect machine.» «But you're saying that it could be changed?» she asked. «Oh, sure. Well, it has been changed. The first one had just enough power to blink an egg ten feet across Billy Bob's workshop, and it was ten by ten feet itself and tied into a computer the size of this ship. They've made them smaller.» He envisioned a generator. The heart of it was amazingly simple, an electronically shaped magnetic field in a cloud chamber, highly compressed. Most of the bulk of a generator was made up of the computer, which was necessary to make the multi-billion calculations required to shape the magnetic charge, and by the ionized chambers in which the charge was stored. «Pete, maybe you'd better sleep on it,» Jan suggested. «You'll have a fresh perspective on whatever it is you're working toward when you're rested.» «There's a body of research,» he muttered, speaking to himself. He pounded the thumb end of his fist onto his forehead. Jan could hear the sound of it, thump, thump, thump. She cringed, almost rose to stop him, then sighed and sat back. «Now who the hell was it?» he asked. «Larson. Parson.» Thump, thump. «You're going to beat your brains out,» she said. «What's left of them?» He paced. «Person. Lewson.» He snapped his fingers. «Geson. Jan, punch up Alex Geson on the library viewer. What I want is something about the field mechanics of a blink generator.» She had it within seconds. «Alex J. Greson,» she said. «A Definitive Study of Blink Field Mechanics.» «That's it.» He sat and started rolling the film. To Jan, it was a mishmash of complicated formulae, of incomprehensible scientific jargon. It took Pete back to second-year theory classes at the Academy. He skipped, read, fingered his skull, drank the coffee which Jan poured him. After two hours he was flipping back and forth between an analysis of the field in the first blink generators and what was, at the time of Greson's work, a modern generator. Greson himself was long dead. His book was a standard on the subject of the blink field, and it was over three hundred years old. The work traced the development of the generator from its beginning, and much of the experimentation done by Greson had been termed useless. Endless experimentation had proved that only one configuration of magnetic field produced the blink effect. Only one configuration would cause an object, or a man, to cease to exist and exist almost simultaneously in another spot. Change the field and you had an expensive, powerful magnet capable of doing nothing but moving ions inside the cloud chamber. But there was something there, something which kept nagging at Pete. He turned off the reader, sighed. «Jan, I know I'm not much, but will you take a gamble with me?» «Don't you talk about my man like that,» she said, rising to go to him, to press against his shoulder and sooth her hand over his rumpled hair. «But I'll take any gamble with you.» «It's just money,» he said. «A good chunk out of our pay for this tour.» «You do what you need to do,» she said. He swiveled to the communications panel and activated the Blinkstater. It took a half hour to perform what could have been considered a minor miracle. He was connected to a computer long, long parsecs away on old Earth. All Academy cadets visited Earth at least once. The plebe class took their first outing on Earth. It would always be a high spot in Pete Jaynes' life. There he'd seen the museums, the preserved city, the vast, hundred-acre tract of original wilderness. The air had been cleaned over the centuries of its pre-space-age pollution. The streams ran clear and sweet. It had been like coming home. No one ever visited old Earth without that feeling, because from that small, blue planet man had struggled up over a thousand years ago, had flexed his wings on flying bombs, on combustion rockets. He'd walked on Earth's satellite in a miracle of dangerous engineering with those old fire-breathing dragons. He'd been crowded in his billions there on the good, blue planet, and he'd come close to possible termination of the race with his nuclear weapons. He'd actually detonated nuclear bombs in the clean, sweet air, oblivious to the p