There is one fact no sane man can quarrel
with ... everything has a beginning and an end.
But some men aren't sane; thus it isn't always so!

No, you're wrong. I'm not your father's ghost, even if I do look a bit like him. But it's a longish story, and you might as well let me in. You will, you know, so why quibble about it? At least, you always have ... or do ... or will. I don't know, verbs get all mixed up. We don't have the right attitude toward tenses for a situation like this.

Anyhow, you'll let me in. I did, so you will.

Thanks. You think you're crazy, of course, but you'll find out you aren't. It's just that things are a bit confused. And don't look at the machine out there too long—until you get used to it, you'll find it's hard on the eyes, trying to follow where the vanes go. You'll get used to it, of course, but it will take about thirty years.

You're wondering whether to give me a drink, as I remember it. Why not? And naturally, since we have the same tastes, you can make the same for me as you're having. Of course we have the same tastes—we're the same person. I'm you thirty years from now, or you're me. I remember just how you feel; I felt the same way when he—that is, of course, I or we—came back to tell me about it, thirty years ago.

Here, have one of these. You'll get to like them in a couple more years. And you can look at the revenue stamp date, if you still doubt my story. You'll believe it eventually, though, so it doesn't matter.

Right now, you're shocked. It's a real wrench when a man meets himself for the first time. Some kind of telepathy seems to work between two of the same people. You sense things. So I'll simply go ahead talking for half an hour or so, until you get over it. After that you'll come along with me. You know, I could try to change things around by telling what happened to me; but he—I—told me what I was going to do, so I might as well do the same. I probably couldn't help telling you the same thing in the same words, even if I tried—and I don't intend to try. I've gotten past that stage in worrying about all this.

So let's begin when you get up in half an hour and come out with me. You'll take a closer look at the machine, then. Yes, it'll be pretty obvious it must be a time machine. You'll sense that, too. You've seen it, just a small little cage with two seats, a luggage compartment, and a few buttons on a dash. You'll be puzzling over what I'll tell you, and you'll be getting used to the idea that you are the man who makes atomic power practical. Jerome Boell, just a plain engineer, the man who put atomic power in every home. You won't exactly believe it, but you'll want to go along.

I'll be tired of talking by then, and in a hurry to get going. So I cut off your questions, and get you inside. I snap on a green button, and everything seems to cut off around us. You can see a sort of foggy nothing surrounding the cockpit; it is probably the field that prevents passage through time from affecting us. The luggage section isn't protected, though.

You start to say something, but by then I'm pressing a black button, and everything outside will disappear. You look for your house, but it isn't there. There is exactly nothing there—in fact, there is no there. You are completely outside of time and space, as best you can guess how things are.

You can't feel any motion, of course. You try to reach a hand out through the field into the nothing around you and your hand goes out, all right, but nothing happens. Where the screen ends, your hand just turns over and pokes back at you. Doesn't hurt, and when you pull your arm back, you're still sound and uninjured. But it looks frightening and you don't try it again.

Then it comes to you slowly that you're actually traveling in time. You turn to me, getting used to the idea. "So this is the fourth dimension?" you ask.

Then you feel silly, because you'll remember that I said you'd ask that. Well, I asked it after I was told, then I came back and told it to you, and I still can't help answering when you speak.

"Not exactly," I try to explain. "Maybe it's no dimension—or it might be the fifth; if you're going to skip over the so-called fourth without traveling along it, you'd need a fifth. Don't ask me. I didn't invent the machine and I don't understand it."

"But...."

I let it go, and so do you. If you don't, it's a good way of going crazy. You'll see later why I couldn't have invented the machine. Of course, there may have been a start for all this once. There may have been a time when you did invent the machine—the atomic motor first, then the time-machine. And when you closed the loop by going back and saving yourself the trouble, it got all tangled up. I figured out once that such a universe would need some seven or eight time and space dimensions. It's simpler just to figure that this is the way time got bent back on itself. Maybe there is no machine, and it's just easier for us to imagine it. When you spend thirty years thinking about it, as I did—and you will—you get further and further from an answer.

Anyhow, you sit there, watching nothing all around you, and no time, apparently, though there is a time effect back in the luggage space. You look at your watch and it's still running. That means you either carry a small time field with you, or you are catching a small increment of time from the main field. I don't know, and you won't think about that then, either.

I'm smoking, and so are you, and the air in the machine is getting a bit stale. You suddenly realize that everything in the machine is wide open, yet you haven't seen any effects of air loss.

"Where are we getting our air?" you ask. "Or why don't we lose it?"

"No place for it to go," I explain. There isn't. Out there is neither time nor space, apparently. How could the air leak out? You still feel gravity, but I can't explain that, either. Maybe the machine has a gravity field built in, or maybe the time that makes your watch run is responsible for gravity. In spite of Einstein, you have always had the idea that time is an effect of gravity, and I sort of agree, still.

Then the machine stops—at least, the field around us cuts off. You feel a dankish sort of air replace the stale air, and you breathe easier, though we're in complete darkness, except for the weak light in the machine, which always burns, and a few feet of rough dirty cement floor around. You take another cigaret from me and you get out of the machine, just as I do.

I've got a bundle of clothes and I start changing. It's a sort of simple, short-limbed, one-piece affair I put on, but it feels comfortable.

"I'm staying here," I tell you. "This is like the things they wear in this century, as near as I can remember it, and I should be able to pass fairly well. I've had all my fortune—the one you make on that atomic generator—invested in such a way I can get it on using some identification I've got with me, so I'll do all right. I know they still use some kind of money, you'll see evidence of that. And it's a pretty easygoing civilization, from what I could see. We'll go up and I'll leave you. I like the looks of things here, so I won't be coming back with you."

You nod, remembering I've told you about it. "What century is this, anyway?"

I'd told you that, too, but you've forgotten. "As near as I can guess, it's about 2150. He told me, just as I'm telling you, that it's an interstellar civilization."

You take another cigaret from me, and follow me. I've got a small flashlight and we grope through a pile of rubbish, out into a corridor. This is a sub-sub-sub-basement. We have to walk up a flight of stairs, and there is an elevator waiting, fortunately with the door open.

"What about the time machine?" you ask.

"Since nobody ever stole it, it's safe."

We get in the elevator, and I say "first" to it. It gives out a coughing noise and the basement openings begin to click by us. There's no feeling of acceleration—some kind of false gravity they use in the future. Then the door opens, and the elevator says "first" back at us.

It's obviously a service elevator and we're in a dim corridor, with nobody around. I grab your hand and shake it. "You go that way. Don't worry about getting lost; you never did, so you can't. Find the museum, grab the motor, and get out. And good luck to you."

You act as if you're dreaming, though you can't believe it's a dream. You nod at me and I move out into the main corridor. A second later, you see me going by, mixed into a crowd that is loafing along toward a restaurant, or something like it, that is just opening. I'm asking questions of a man, who points, and I turn and move off.

You come out of the side corridor and go down a hall, away from the restaurant. There are quiet little signs along the hall. You look at them, realizing for the first time that things have changed.

Steij:neri, Faunten, Z:rgat Dispenseri. The signs are very quiet and dignified. Some of them can be decoded to stationery shops, fountains, and the like. What a zergot is, you don't know. You stop at a sign that announces: Trav:l Biwrou—F:rst-Clas Twrz—Marz, Viin*s, and x: Trouj:n Planets. Spej:l reits tu aol s*nz wixin 60 lyt iirz! But there is only a single picture of a dull-looking metal sphere, with passengers moving up a ramp, and the office is closed. You begin to get the hang of the spelling they use, though.

Now there are people around you, but nobody pays much attention to you. Why should they? You wouldn't care if you saw a man in a leopard-skin suit; you'd figure it was some part in a play and let it go. Well, people don't change much.

You get up your courage and go up to a boy selling something that might be papers on tapes.

"Where can I find the Museum of Science?"

"Downayer rien turn lefa the sign. Stoo bloss," he tells you. Around you, you hear some pretty normal English, but there are others using stuff as garbled as his. The educated and uneducated? I don't know.

You go right until you find a big sign built into the rubbery surface of the walk: Miuzi:m *v Syens. There's an arrow pointing and you turn left. Ahead of you, two blocks on, you can see a pink building, with faint aqua trimming, bigger than most of the others. They are building lower than they used to, apparently. Twenty floors up seems about the maximum. You head for it, and find the sidewalk is marked with the information that it is the museum.

You go up the steps, but you see that it seems to be closed. You hesitate for a moment, then. You're beginning to think the whole affair is complete nonsense, and you should get back to the time machine and go home. But then a guard comes to the gate. Except for the short legs in his suit and the friendly grin on his face, he looks like any other guard.

What's more, he speaks pretty clearly. Everyone says things in a sort of drawl, with softer vowels and slurred consonants, but it's rather pleasant.

"Help you, sir? Oh, of course. You must be playing in 'Atoms and Axioms.' The museum's closed, but I'll be glad to let you study whatever you need for realism in your role. Nice show. I saw it twice."

"Thanks," you mutter, wondering what kind of civilization can produce guards as polite as that. "I—I'm told I should investigate your display of atomic generators."

He beams at that. "Of course." The gate is swung to behind you, but obviously he isn't locking it. In fact, there doesn't seem to be a lock. "Must be a new part. You go down that corridor, up one flight of stairs and left. Finest display in all the known worlds. We've got the original of the first thirteen models. Professor Jonas was using them to check his latest theory of how they work. Too bad he could not explain the principle, either. Someone will, some day, though. Lord, the genius of that twentieth century inventor! It's quite a hobby with me, sir. I've read everything I could get on the period. Oh—congratulations on your pronunciation. Sounds just like some of our oldest tapes."

You get away from him, finally, after some polite thanks. The building seems deserted and you wander up the stairs. There's a room on your right filled with something that proclaims itself the first truly plastic diamond former, and you go up to it. As you come near, it goes through a crazy wiggle inside, stops turning out a continual row of what seem to be bearings, and slips something the size of a penny toward you.

"Souvenir," it announces in a well-modulated voice. "This is a typical gem of the twentieth century, properly cut to 58 facets, known technically as a Jaegger diamond, and approximately twenty carats in size. You can have it made into a ring on the third floor during morning hours for one-tenth credit. If you have more than one child, press the red button for the number of stones you desire."

You put it in your pocket, gulping a little, and get back to the corridor. You turn left and go past a big room in which models of spaceships—from the original thing that looks like a V-2, and is labeled first Lunar rocket, to a ten-foot globe, complete with miniature manikins—are sailing about in some kind of orbits. Then there is one labeled Wep:nz, filled with everything from a crossbow to a tiny rod four inches long and half the thickness of a pencil, marked Fynal Hand Arm. Beyond is the end of the corridor, and a big place that bears a sign, Mad:lz *v Atamic Pau:r Sorsez.

By that time, you're almost convinced. And you've been doing a lot of thinking about what you can do. The story I'm telling has been sinking in, but you aren't completely willing to accept it.

You notice that the models are all mounted on tables and that they're a lot smaller than you thought. They seem to be in chronological order, and the latest one, marked 2147—Rincs Dyn*pat:, is about the size of a desk telephone. The earlier ones are larger, of course, clumsier, but with variations, probably depending on the power output. A big sign on the ceiling gives a lot of dope on atomic generators, explaining that this is the first invention which leaped full blown into basically final form.

You study it, but it mentions casually the inventor, without giving his name. Either they don't know it, or they take it for granted that everyone does, which seems more probable. They call attention to the fact that they have the original model of the first atomic generator built, complete with design drawings, original manuscript on operation, and full patent application.

They state that it has all major refinements, operating on any fuel, producing electricity at any desired voltage up to five million, any chosen cyclic rate from direct current to one thousand megacycles, and any amperage up to one thousand, its maximum power output being fifty kilowatts, limited by the current-carrying capacity of the outputs. They also mention that the operating principle is still being investigated, and that only such refinements as better alloys and the addition of magnetric and nucleatric current outlets have been added since the original.

So you go to the end and look over the thing. It's simply a square box with a huge plug on each side, and a set of vernier controls on top, plus a little hole marked, in old-style spelling, Drop BBs or wire here. Apparently that's the way it's fueled. It's about one foot on each side.

"Nice," the guard says over your shoulder. "It finally wore out one of the cathogrids and we had to replace that, but otherwise it's exactly as the great inventor made it. And it still operates as well as ever. Like to have me tell you about it?"

"Not particularly," you begin, and then realize bad manners might be conspicuous here. While you're searching for an answer, the guard pulls something out of his pocket and stares at it.

"Fine, fine. The mayor of Altasecarba—Centaurian, you know—is arriving, but I'll be back in about ten minutes. He wants to examine some of the weapons for a monograph on Centaurian primitives compared to nineteenth century man. You'll pardon me?"

You pardon him pretty eagerly and he wanders off happily. You go up to the head of the line, to that Rinks Dynapattuh, or whatever it transliterates to. That's small and you can carry it. But the darned thing is absolutely fixed. You can't see any bolts, but you can't budge it, either.

You work down the line. It'd be foolish to take the early model if you can get one with built-in magnetic current terminals—Ehrenhaft or some other principle?—and nuclear binding-force energy terminals. But they're all held down by the same whatchamaycallem effect.

And, finally, you're right back beside the original first model. It's probably bolted down, too, but you try it tentatively and you find it moves. There's a little sign under it, indicating you shouldn't touch it, since the gravostatic plate is being renewed.

Well, you won't be able to change the time cycle by doing anything I haven't told you, but a working model such as that is a handy thing. You lift it; it only weighs about fifty pounds! Naturally, it can be carried.

You expect a warning bell, but nothing happens. As a matter of fact, if you'd stop drinking so much of that scotch and staring at the time machine out there now, you'd hear what I'm saying and know what will happen to you. But of course, just as I did, you're going to miss a lot of what I say from now on, and have to find out for yourself. But maybe some of it helps. I've tried to remember how much I remembered, after he told me, but I can't be sure. So I'll keep on talking. I probably can't help it, anyhow. Pre-set, you might say.

Well, you stagger down the corridor, looking out for the guard, but all seems clear. Then you hear his voice from the weapons room. You bend down and try to scurry past, but you know you're in full view. Nothing happens, though.

You stumble down the stairs, feeling all the futuristic rays in the world on your back, and still nothing happens. Ahead of you, the gate is closed. You reach it and it opens obligingly by itself. You breathe a quick sigh of relief and start out onto the street.

Then there's a yell behind you. You don't wait. You put one leg in front of the other and you begin racing down the walk, ducking past people, who stare at you with expressions you haven't time to see. There's another yell behind you.

Something goes over your head and drops on the sidewalk just in front of your feet, with a sudden ringing sound. You don't wait to find out about that, either. Somebody reaches out a hand to catch you and you dart past.

The street is pretty clear now and you jolt along, with your arms seeming to come out of the sockets, and that atomic generator getting heavier at every step.

Out of nowhere, something in a blue uniform about six feet tall and on the beefy side appears—and the badge hasn't changed much. The cop catches your arm and you know you're not going to get away, so you stop.

"You can't exert yourself that hard in this heat, fellow," the cop says. "There are laws against that, without a yellow sticker. Here, let me grab you a taxi."

Reaction sets in a bit and your knees begin to buckle, but you shake your head and come up for air.

"I—I left my money home," you begin.

The cop nods. "Oh, that explains it. Fine, I won't have to give you an appearance schedule. But you should have come to me." He reaches out and taps a pedestrian lightly on the shoulder. "Sir, an emergency request. Would you help this gentleman?"

The pedestrian grins, looks at his watch, and nods. "How far?"

You did notice the name of the building from which you came and you mutter it. The stranger nods again, reaches out and picks up the other side of the generator, blowing a little whistle the cop hands him. Pedestrians begin to move aside, and you and the stranger jog down the street at a trot, with a nice clear path, while the cop stands beaming at you both.

That way, it isn't so bad. And you begin to see why I decided I might like to stay in the future. But all the same, the organized cooperation here doesn't look too good. The guard can get the same and be there before you.

And he is. He stands just inside the door of the building as you reach it. The stranger lifts an eyebrow and goes off at once when you nod at him, not waiting for thanks. And the guard comes up, holding some dinkus in his hand, about the size of a big folding camera and not too dissimilar in other ways. He snaps it open and you get set to duck.

"You forgot the prints, monograph, and patent applications," he says. "They go with the generator—we don't like to have them separated. A good thing I knew the production office of 'Atoms and Axioms' was in this building. Just let us know when you're finished with the model and we'll pick it up."

You swallow several sets of tonsils you had removed years before, and take the bundle of papers he hands you out of the little case. He pumps you for some more information, which you give him at random. It seems to satisfy your amiable guard friend. He finally smiles in satisfaction and heads back to the museum.

You still don't believe it, but you pick up the atomic generator and the information sheets, and you head down toward the service elevator. There is no button on it. In fact, there's no door there.

You start looking for other doors or corridors, but you know this is right. The signs along the halls are the same as they were.

Then there's a sort of cough and something dilates in the wall. It forms a perfect door and the elevator stands there waiting. You get in, gulping out something about going all the way down, and then wonder how a machine geared for voice operation can make anything of that. What the deuce would that lowest basement be called? But the elevator has closed and is moving downward in a hurry. It coughs again and you're at the original level. You get out—and realize you don't have a light.

You'll never know what you stumbled over, but, somehow, you move back in the direction of the time machine, bumping against boxes, staggering here and there, and trying to find the right place by sheer feel. Then a shred of dim light appears; it's the weak light in the time machine.

You've located it.

You put the atomic generator in the luggage space, throw the papers down beside it, and climb into the cockpit, sweating and mumbling. You reach forward toward the green button and hesitate. There's a red one beside it and you finally decide on that.

Suddenly, there's a confused yell from the direction of the elevator and a beam of light strikes against your eyes, with a shout punctuating it. Your finger touches the red button.

You'll never know what the shouting was about—whether they finally doped out the fact that they'd been robbed, or whether they were trying to help you. You don't care which it is. The field springs up around you and the next button you touch—the one on the board that hasn't been used so far—sends you off into nothingness. There is no beam of light, you can't hear a thing, and you're safe.

It isn't much of a trip back. You sit there smoking and letting your nerves settle back to normal. You notice a third set of buttons, with some pencil marks over them—"Press these to return to yourself 30 years"—and you begin waiting for the air to get stale. It doesn't because there is only one of you this time.

Instead, everything flashes off and you're sitting in the machine in your own back yard.

You'll figure out the cycle in more details later. You get into the machine in front of your house, go to the future in the sub-basement, land in your back yard, and then hop back thirty years to pick up yourself, landing in front of your house. Just that. But right then, you don't care. You jump out and start pulling out that atomic generator and taking it inside.

It isn't hard to disassemble, but you don't learn a thing; just some plates of metal, some spiral coils, and a few odds and ends—all things that can be made easily enough, all obviously of common metals. But when you put it together again, about an hour later, you notice something.

Everything in it is brand-new and there's one set of copper wires missing! It won't work. You put some #12 house wire in, exactly like the set on the other side, drop in some iron filings, and try it again.

And with the controls set at 120 volts, 60 cycles and 15 amperes, you get just that. You don't need the power company any more. And you feel a little happier when you realize that the luggage space wasn't insulated from time effects by a field, so the motor has moved backward in time, somehow, and is back to its original youth—minus the replaced wires the guard mentioned—which probably wore out because of the makeshift job you've just done.

But you begin getting more of a jolt when you find that the papers are all in your own writing, that your name is down as the inventor, and that the date of the patent application is 1951.

It will begin to soak in, then. You pick up an atomic generator in the future and bring it back to the past—your present—so that it can be put in the museum with you as the inventor so you can steal it to be the inventor. And you do it in a time machine which you bring back to yourself to take yourself into the future to return to take back to yourself....

Who invented what? And who built which?

Before long, your riches from the generator are piling in. Little kids from school are coming around to stare at the man who changed history and made atomic power so common that no nation could hope to be anything but a democracy and a peaceful one—after some of the worst times in history for a few years. Your name eventually becomes as common as Ampere, or Faraday, or any other spelled without a capital letter.

But you're thinking of the puzzle. You can't find any answer.

One day you come across an old poem—something about some folks calling it evolution and others calling it God. You go out, make a few provisions for the future, and come back to climb into the time machine that's waiting in the building you had put around it. Then you'll be knocking on your own door, thirty years back—or right now, from your view—and telling your younger self all these things I'm telling you.

But now....

Well, the drinks are finished. You're woozy enough to go along with me without protest, and I want to find out just why those people up there came looking for you and shouting, before the time machine left.

Let's go.