Herman Chouns was a man of hunches. Sometimes he was right; sometimes he was wrong-about fifty-fifty. Still, considering that one has the whole universe of possibilities from which to pull a right answer, fifty-fifty begins to look pretty good.

Chouns wasn't always as pleased with the matter as might be expected. It put too much of a strain on him. People would huddle around a problem, making nothing of it, then turn to him and say, "What do you think, Chouns? Turn on the old intuition."

And if he came up with something that fizzled, the responsibility for that was made clearly his.

His job, as field explorer, rather made things worse. "Think that planet's worth a closer look?" they would say. "What do you think, Chouns?"

So it was a relief to draw a two-man spot for a change (meaning that the next trip would be to some low-priority place, and the pressure would be off) and, on top of it, to get Allen Smith as partner.

Smith was as matter-of-fact as his name. He said to Chouns the first day out, "The thing about you is that the memory files in your brain are on extraspecial can. Faced with a problem, you remember enough little things that maybe the rest of us don't come up with to make a decision. Calling it a hunch just makes it mysterious, and it isn't."

He rubbed his hair slickly back as he said that. He had light hair that lay down like a skull cap.

Chouns, whose hair was very unruly, and whose nose was snub and a bit off-center, said softly (as was his way), "I think maybe it's telepathy."

"What!"

"Nuts!" said Smith, with loud derision (as was his way)." Scientists have been tracking psionics for a thousand years and gotten nowhere. There's no such thing: noprecognition; no telekinesis; no clairvoyance; and no telepathy."

"I admit that, but consider this. If I get a picture of what each of a group of people are thinking-even though I might not be aware of what was happening-I could integrate the information and come up with an answer. I would know more than any single individual in the group, so I could make a better judgment than the others-sometimes."

"Do you have any evidence at all for that?" Chouns turned his mild brown eyes on the other. "Just a hunch."

They got along well. Chouns welcomed the other's refreshing practicality, and Smith patronized the other's speculations. They often disagreed but never quarreled,

Even when they reached their objective, which was a globular cluster that had never felt the energy thrusts of a human-designed nuclear reactor before, increasing tension did not worsen matters.

Smith said, "Wonder what they do with all this data back on Earth. Seems a waste sometimes."

Chouns said, "Earth is just beginning to spread out. No telling how far humanity will move out into the galaxy, given a million years or so. All the data we can get on any world will come in handy someday,"

"You sound like a recruiting manual for the Exploration Teams, Think there'll be anything interesting in that thing?" He indicated the visi-plate on which the no-longer distant cluster was centered like spilled talcum powder.

"Maybe. I've got a hunch-" Chouns stopped, gulped, blinked once or twice, and then smiled weakly.

Smith snorted, "Let's get a fix on the nearest stargroups and make a random pass through the thickest of it. One gets you ten, we find a McKomin ratio under 0.2,"

"You'll lose," murmured Chouns. He felt the quick stir of excitement that always came when new worlds were about to be spread beneath them. It was a most contagious feeling, and it caught hundreds of youngsters each year. Youngsters, such as he had been once, flocked to the Teams, eager to see the worlds their descendants someday would call their own, each an explorer-

They got their fix (made their first close-quarters hyperspatial jump into the cluster, and began scanning stars for planetary systems. The computers did their work; the information files grew steadily, and all proceeded in satisfactory routine-until at system 23, shortly after completion of the jump, the ship's hyperatomic motors failed.

Chouns muttered, "Funny. The analyzers don't say what's wrong."

He was right. The needles wavered erratically, never stopping once for a reasonable length of time, so that no diagnosis was indicated. And, as a consequence, no repairs could be carried through.

"Never saw anything like it," growled Smith. "We'll have to shut everything off and diagnose manually."

"We might as well do it comfortably," said Chouns, who was already at the telescopes. "Nothing's wrong with the ordinary spacedrive, and there are two decent planets in this system."

"Oh? How decent and which ones?"

"The first and second out of four: Both water-oxygen. The first is a bit warmer and larger than Earth; the second a bit colder and smaller. Fair enough?"

"Life?"

"Both. Vegetation, anyway." Smith grunted. There was nothing in that to surprise anyone; vegetation occurred more often than not on water-oxygen worlds. And, unlike animal life, vegetation could be seen telescopically-or, more precisely, spectroscopically. Only four photochemical pigments had ever been found in any plant form, and each could be detected by the nature of the light it reflected.

Chouns said, "Vegetation on both planets is chlorophyll type, no less. It'll be just like Earth; real homey."

Smith said, "Which is closer?"

"Number two, and we're on our way. I have a feeling it's going to be a nice planet."

"I'll judge that by the instruments, if you don't mind," said Smith.

But this seemed to be one of Chouns's correct hunches.

The planet was a tame one with an intricate ocean network that insured a climate of small temperature range. The mountain ranges were low and rounded, and the distribution of vegetation indicated high and widespread fertility.

Chouns was at the controls for the actual landing.

Smith grew impatient. "What are you picking and choosing for? One place is like another."

"I'm looking for a bare spot, " said Chouns. "No use burning up an acre of plant life."

"What if you do?"

"What if I don't?" said Chouns, and found his bare spot.

It was only then, after landing, that they realized a small part of what they had tumbled into.

"Jumping space-warps," said Smith.

Chouns felt stunned. Animal life was much rarer than vegetation, and even the glimmerings of intelligence were far rarer still; yet here, not half a mile away from landing point, was a clustering of low, thatched huts that were obviously the product of a primitive intelligence.

"Careful, " said Smith dazedly.

"I don't think there's any harm," said Chouns. He stepped out onto the surface of the planet with firm confidence; Smith followed.

Chouns controlled his excitement with difficulty. "This is terrific. No one's ever reported anything better than caves or woven tree-branches before."

"I hope they're harmless."

"It's too peaceful for them to be anything else. Smell the air."

Coming down to landing, the terrain-to all points of horizon, except where a low range of hills broke the even line-had been colored a soothing pale pink, dappled against the chlorophyll green. At closer quarters the pale pink broke up into individual flowers, fragile and fragrant. Only the areas in the immediate neighborhood of the huts were amber with something that looked like a cereal grain.

Creatures were emerging from the huts, moving closer to the ship with a kind of hesitating trust. They had fourlegs and a sloping body which stood three feet high at the shoulders. Their heads were set firmly on those shoulders, with bulging eyes (Chouns counted six) set in a circle and capable of the most disconcertingly independent motion. (That makes up for the immovability of the head, thought Chouns.)

Each animal had a tail that forked at the end, forming two sturdy fibrils that each animal held high. The fibrils maintained a rapid tremor that gave them a hazy, blurred look.

"Come on," said Chouns. "They won't hurt us; I'm sure of it."

The animals surrounded the men at a cautious distance. Their tails made a modulated humming noise.

"They might communicate that way," said Chouns. " And I think it's obvious they're vegetarians." He pointed toward one of the huts, where a small member of the species sat on its haunches, plucking at the amber grain with his tails, and flickering an ear of it through his mouth like a man sucking a series of maraschino cherries off a toothpick.

"Human beings eat lettuce," said Smith, "but that doesn't prove anything."

More of the tailed creatures emerged, hovered about the men for a moment, then vanished off into the pink and green.

"Vegetarians," said Chouns firmly. "Look at the way they cultivate the main crop."

The main crop, as Chouns called it, consisted of a coronet of soft green spikes, close to the ground. Out of the center of the coronet grew a hairy stem which, at two-inch intervals, shot out fleshy, veined buds that almost pulsated, they seemed so "Vitally alive. The stem ended at the tip with the pale pink blossoms that, except for the color, were the most Earthly thing about the plants.

The plants were laid out in rows and files with geometric precision. The soil about each was well loosened and powdered with a foreign substance that could be nothing but fertilizer. Narrow passageways, just wide enough for an animal to pass along, crisscrossed the field, and eachpassageway was lined with narrow sluiceways, obviously for water.

The animals were spread through the fields now, working diligently, heads bent. Only a few remained in the neighborhood of the two men.

Chouns nodded. "They're good farmers."

"Not bad," agreed Smith. He walked briskly toward the nearest of the pale pink blooms and reached for one; but six inches short of it he was stopped by the sound of tail vibrations keening to shrillness, and by the actual touch of a tail upon his arm. The touch was delicate but firm, interposing itself between Smith and the plants.

Smith fell back. "What in Space-" He had half reached for his blaster when Chouns said, "No cause for excitement; take it easy."

Half a dozen of the creatures were now gathering about the two, offering stalks of grain humbly and gently, some using their tails, some nudging it forward with their muzzles.

Chouns said, "They're friendly enough. Picking a bloom might be against their customs; the plants probably have to be treated according to rigid rules. Any culture that has agriculture probably has fertility rites, and Lord knows what that involves. The rules governing the cultivation of the plants must be strict, or there wouldn't be those accurate measured rows...Space, won't they sit up back home when they hear this?"

The tail humming shot up in pitch again, and the creatures near them fell back. Another member of the species was emerging from a larger hut in the center of the group.

"The chief, I suppose," muttered Chouns. The new one advanced slowly, tail high, each fibril encircling a small black object. At a distance of five feet its tail arched forward.

"He's giving it to us," said Smith in astonishment, "and Chouns, for God's sake, look at it."

Chouns was doing so, feverishly. He choked out, "They're Gamow hyperspatial sighters. Those are ten-thousand-dollar instruments."

Smith emerged from the ship again, after an hour within. He shouted from the ramp in high excitement, "They work. They're perfect. We're rich."

Chouns called back, "I've been checking through their huts. I can't find any more."

"Don't sneeze at just two. Good Lord, these are as negotiable as a handful of cash."

But Chouns still looked about, arms akimbo, exasperated. Three of the tailed creatures had dogged him from hut to hut-patiently, never interfering, but remaining always between him and the geometrically cultivated pale pink blossoms. Now they stared multiply at him.

Smith said, "It's the latest model, too. Look here." He pointed to the raised lettering which said Model X-20. Gamow Products. Warsaw. European Sector.

Chouns glanced at it and said impatiently, "What interests me is getting more. I know there are more Gamow sighters somewhere, I want them." His cheeks were flushed and his breathing heavy.

The sun was setting; the temperature dropped below the comfortable point. Smith sneezed twice, then Chouns.

"We'll catch pneumonia," snuffled Smith.

"I've got to make them understand," said Chouns stubbornly. He had eaten hastily through a can of pork sausage, had gulped down a can of coffee, and was ready to try again.

He held the sighter high. "More," he said, "more," making encircling movements with his arms. He pointed to one sighter, then to the other, then to the imaginary additional ones lined up before him. "More."

Then, as the last of the sun dipped below the horizon, a vast hum arose from all parts of the field as every creature in sight ducked its head, lifted its forked tail, and vibrated it into screaming invisibility in the twilight.

"What in Space," muttered Smith uneasily. "Hey, look at the blooms!" He sneezed again.

The pale pink flowers were shriveling visibly. Chouns shouted to make himself heard above the hum, "It may be a reaction to sunset. You know, the blooms close at night. The noise may be a religious observance of the fact."

A soft flick of a tail across his wrist attracted Chouns's instant attention. The tail he had felt belonged to the nearest creature; and now it was raised to the sky, toward a bright object low on the western horizon. The tail bent downward to point to the sighter, then up again to the star.

Chouns said excitedly, "Of course-the inner planet; the other habitable one. These must have come from there." Then, reminded by the thought, he cried in sudden shock, "Hey, Smith, the hyperatomic motors are still out."

Smith looked shocked, as though he had forgotten, too; then he mumbled, "Meant to tell you-they're allright."

"You fixed them?"

"Never touched them. But when I was testing the sighters I used the hyperatomics and they worked. I didn't pay any attention at the time; I forgot there was anything wrong. Anyway, they worked."

"Then let's go," said Chouns at once. The thought of sleep never occurred to him.

Neither one slept through the six-hour trip. They remained at the controls in an almost drug-fed passion. Once again they chose a bare spot on which to land.

It was hot with an afternoon subtropical heat; and a broad, muddy river moved placidly by them. The near bank was of hardened mud, riddled with large cavities.

The two men stepped out onto planetary surface and Smith cried hoarsely, "Chouns, look at that!"

Chouns shook off the other's grasping hand. He said, "The same plants! I'll be damned."

There was no mistaking the pale pink blossoms, the stalk with its veined buds, and the coronet of spikes below. Again there was the geometric spacing, the careful planting and fertilization, the irrigation canals.

Smith said, "We haven't made a mistake and circled-"

"Oh, look at the sun; it's twice the diameter it was be-

fore. And look there."

Out of the nearest burrows in the river bank smoothly tan and sinuous objects, as limbless as snakes, emerged. They were a foot in diameter, ten feet in length. The two ends were equally featureless, equally blunt. Midway along their upper portions were bulges. All the bulges, as though on signal, grew before their eyes to fat ovals, split in two to form lipless, gaping mouths that opened and closed with a sound like a forest of dry sticks clapping together.

Then, just as on the outer planet, once their curiosities were satisfied and their fears calmed, most of the creatures drifted away toward the carefully cultivated field of plants.

Smith sneezed. The force of expelled breath against the sleeve of his jacket raised a powdering of dust.

He stared at that with amazement, then slapped himself and said, "Damn it, I'm dusty." The dust rose like a pale pink fog. "You, too," he added, slapping Chouns.

Both men sneezed with abandon.

"Picked it up on the other planet, I suppose," said Chouns.

"We can work up an allergy."

"Impossible." Chouns held up one of the sighters and shouted at the snake-things, "Do you have any of these?"

For a while there was nothing in answer but the splashing of water, as some of the snake things slid into the river and emerged with silvery clusters of water life, which they tucked beneath their bodies toward some hidden mouth.

But then one snake-thing, longer than the others, came thrusting along the ground, one blunt end raised questingly some two inches, weaving blindly side to side. The bulb in its center swelled gently at first, then alarmingly, splitting in two with an audible pop. There, nestling within the two halves, were two more sighters, the duplicates of the first two.

Chouns said ecstatically, "Lord in heaven, isn't that beautiful?"

He stepped hastily forward. reaching out for the objects. The swelling that held them thinned and lengthened,forming what were almost tentacles. They reached out toward him.

Chouns was laughing. They were Gamow sighters all right; duplicates, absolute duplicates, of the first two. Chouns fondled them.

Smith was shouting, "Don't you hear me? Chouns, damn it, listen to me."

Chouns said, "What?" He was dimly aware that Smith had been yelling at him for over a minute.

"Look at the flowers, Chouns."

They were closing, as had those on the other planet, and among the rows the snake-things reared upward, balancing on one end and swaying with a queer, broken rhythm. Only the blunt ends of them were visible above the pale pink.

Smith said, "You can't say they're closing up because of nightfall. It's broad day."

Chouns shrugged. "Different planet, different plant. Come on! We've only got two sighters here; there must be more."

"Chouns, let's go home." Smith firmed his legs into two stubborn pillars and the grip he held on Chouns's collar tightened.

Chouns's reddened face turned back toward him indignantly. "What are you doing?"

"I'm getting ready to knock you out if you don't come back with me at once, into the ship."

For a moment Chouns stood irresolute; then a certain wildness about him faded, a certain slackening took place, and he said, "All right. "

They were halfway out of the starcluster. Smith said, "How are you?"

Chouns sat up in his bunk and rumpled his hair. "Normal, I guess; sane again. How long have I been sleeping?"

"Twelve hours."

"What about you?"

"I've catnapped." Smith turned ostentatiously to the instruments and made some minor adjustments. He said self-consciously, "Do you know what happened back there on those planets?"

Chouns said slowly, "Do you?"

"I think so."

"Oh? May I hear?"

Smith said, "It was the same plant on both planets. You'll grant that?"

"I most certainly do."

"It was transplanted from one planet to the other, somehow. It grows on both planets perfectly well; but occasionally-to maintain vigor, I imagine-there must be crossfertilization, the two strains mingling. That sort of thing happens on Earth often enough."

"Crossfertilization for vigor? Yes."

"But we were the agents that arranged for the mingling. We landed on one planet and were coated with pollen. Remember the blooms closing? That must have been just after they released their pollen; and that's what was making us sneeze, too. Then we landed on the other planet and knocked the pollen off our clothes. A new hybrid strain win start up. We were just a pair of two-legged bees, Chouns, doing our duty by the flowers."

Chouns smiled tentatively. " An inglorious role, in a way."

"Hen, that's not it. Don't you see the danger? Don't you see why we have to get back home fast?"

"Why?"

"Because organisms don't adapt themselves to nothing. Those plants seem to be adapted to interplanetary fertilization. We even got paid off, the way bees are; not with nectar, but with Gamow sighters."

"Well?"

"Well, you can't have interplanetary fertilization unless something or someone is there to do the job. We did it this time, but we were the first humans ever to enter the cluster. So, before this, it must be nonhumans who did it; maybe the same nonhumans who transplanted the blooms in the first place. That means that somewhere in this cluster there is an intelligent race of beings; intelligent enough for space travel. And Earth must know about that."

Slowly Chouns shook his head. Smith frowned. "You find flaws somewhere in the reasoning?"

Chouns put hi!; head between his own palms and looked miserable. "Let's say you've missed almost everything."

"What have I missed?" demanded Smith angrily.

"Your crossfertilization theory is good, as far as it goes, but you haven't considered a few points. When we approached that stellar system our hyperatomic motor went out of order in a way the automatic controls could neither diagnose nor correct. After we landed we made no effort to adjust them. We forgot about them, in fact; and when you handled them later you found they were in perfect order, and were so unimpressed by that that you didn't even mention it to me for another few hours.

"Take something else: How conveniently we chose landing spots near a grouping of animal life on both planets. Just luck? And our incredible confidence in the good will of the creatures. We never even bothered checking atmospheres for trace poisons before exposing ourselves.

"And what bothers me most of all is that I went completely crazy over the Gamow sighters. Why? They're valuable, yes, but not that valuable-and I don't generally go overboard for a quick buck."

Smith had kept an uneasy silence during all that. Now he said, "I don't see that any of that adds up to anything."

"Get off it, Smith; you know better than that. Isn't it obvious to you that we were under mental control from the outside?"

Smith's mouth twisted and caught halfway between derision and doubt. " Are you on the psionic kick again?"

"Yes; facts are facts. I told you that my hunches might be a form of rudimentary telepathy."

"Is that a fact, too? You didn't think so a couple of days ago."

"I think so now. Look, I'm a better receiver than you, and I was more strongly affected. Now that it's over, I understand more about what happened because I received more. Understand?"

"No," said Smith harshly.

"Then listen further. You said yourself the (Gamow sighters were the nectar that bribed us into pollination. You said that."

"All right."

"Well, then, where did they come from? They were Earth products; we even read the manufacturer's name and model on them, letter by letter. Yet, if no human beings have ever been in the cluster, where did the sighters come from? Neither one of us worried about that, then; and you don't seem to worry about it even now."

"Well-"

"What did you do with the sighters after we got on board ship, Smith? You took them from me; I remember that."

"I put them in the safe," said Smith defensively. "Have you touched them since?"

"No."

"Have I?"

"Not as far as I know."

"You have my word I didn't. Then why not open the safe now?"

Smith stepped slowly to the safe. It was keyed to his fingerprints, and it opened. Without looking he reached in. His expression altered and with a sharp cry he first stared at the contents, then scrabbled them out.

He held four rocks of assorted color, each of them roughly rectangular.

"They used our own emotions to drive us," said Chouns softly, as though insinuating the words into the other's stubborn skull one at a time. "They made us think the hyperatomics were wrong so we could land on one of the planets; it didn't matter which, I suppose. They made us think we had precision instruments in our hand after we landed on one so we would race to the other."

"Who are 'they'?" groaned Smith. "The tails or the snakes? Or both?"

"Neither," said Chouns. "It was the plants."

"The plants? The flowers?"

"Certainly. We saw two different sets of animals tending the same species of plant. Being animals ourselves, we assumed the animals were the masters. But why should we assume that? It was the plants that were being taken care of."

"We cultivate plants on Earth, too, Chouns."

"But we eat those plants," said Chouns.

"And maybe those creatures eat their plants, too."

"Let's say I know they don't," said Chouns. "Theymaneuvered us well enough. Remember how careful I was to find a bare spot on which to land."

"I felt no such urge."

"You weren't at the controls; they weren't worried about you. Then, too, remember that we never noticed the pollen, though we were covered with it-not till we were safely on the second planet. Then we dusted the pollen off, on order."

"I never heard anything so impossible."

"Why is it impossible? We don't associate intelligence with plants, because plants have no nervous systems; but these might have. Remember the fleshy buds on the stems? Also, plants aren't free-moving; but they don't have to be if they develop psionic powers and can make use of free-moving animals. They get cared for, fertilized, irrigated, pollinated, and so on. The animals tend them with single-minded devotion and are happy over it because the plants make them feel happy."

"I'm sorry for you," said Smith in a monotone. "If you try to tell this story back on Earth, I'm sorry for you."

"I have no illusions," muttered Chouns, "yet-what can I do but try to warn Earth. You see what they do to animals."

"They make slaves of them, according to you."

"Worse than that. Either the tailed creatures or the snake-things, or both, must have been civilized enough to have developed space travel once; otherwise the plants couldn't be on both planets. But once the plants developed psionic powers (a mutant strain, perhaps), that came to an end. Animals at the atomic stage are dangerous. So they were made to forget; they were reduced to what they are. -Damn it, Smith, those plants are the most dangerous things in the universe. Earth must be informed about them, because some other Earthmen may be entering that cluster."

Smith laughed. "You know, you're completely off base. If those plants really had us under control, why would they let us get away to warn the others?"

Chouns paused. "I don't know." Smith's good humor was restored. He said, "For a minute you had me going, I don't mind telling you."

Chouns rubbed his skull violently. Why were they let go? And for that matter, why did he feel this horrible urgency to warn Earth about a matter with which Earthmen would not come into contact for millennia perhaps?

He thought desperately and something came glimmering. He fumbled for it, but it drifted away. For a moment he thought desperately that it was as though the thought had been pushed away: but then that feeling, too, left.

He knew only that the ship had to remain at full thrust, that they had to hurry.

So. after uncounted years, the proper conditions had come about again. The protospores from two planetary strains of the mother plant met and mingled, sifting together into the clothes and hair and ship of the new animals. Almost at once the hybrid spores formed; the hybrid spores that alone had all the capacity and potentiality of adapting themselves to a new planet.

The spores waited quietly, now, on the ship which, with the last impulse of the mother plant upon the minds of the creatures aboard, was hurtling them at top thrust toward a new and ripe world where free-moving creatures would tend their needs.

The spores waited with the patience of the plant (the all-conquering patience no animal can ever know) for their arrival on a new world-each, in its own tiny way, an explorer-

***

The stories in this book have not been much anthologized. That is the very reason I have chosen them, and it was one of the points Doubleday urged on me. EACH AN EXPLORER has, however, been anthologized twice, once by Judith Merril in 1957 and once by Vic Ghidalia in 1973.

That still isn't much, though. Some of my stories tend to appear many times. A little story I wrote called THE FUN THEY HAD has appeared, to date, at least forty-two times since it was first published, in 1951, and is currently in press for eight more appearances. It may have appeared in other places, too, but I only have forty-two in my library.

You can find the story, if you wish, in my book EARTH IS ROOM ENOUGH (Doubleday, 1957). That's one of the forty-two places.

Editors are always trying to think up gimmicks. Sometimes I am the victim.

On November 14, 1956, I was in the office of Infinity Science Fiction, talking to the editor, Larry Shaw. We got along well together, he and I,* [* I mustn't make that sound exceptional. I get along with nearly everyone.] and I often dropped in to see him when I visited New York.

That day he had an idea. He was to give me the title for a story-the least inspirational title he could think of-and I was to write a short-short, on the spot, based on that title. Then he would give the same title to two other writers and they would do the same.

I asked, cautiously, what the title was, and he said, "Blank."

"Blank?" I said.

"Blank," he said.

So I thought a little and wrote the following story, with the title of BLANK! (with an exclamation point).

Randall Garrett wrote a story entitled Blank? with a question mark, and Harlan Ellison wrote one called Blank with no punctuation at all.

B;ank!

"Presumably," said August Pointdexter, "there is such a thing as overweening pride. The Greeks called it hubris, and considered it to be defiance of the gods, to be followed always by ate, or retribution." He rubbed his pale blue eyes uneasily.

"Very pretty," said Dr. Edward Barron impatiently. "Has that any connection with what I said?" His forehead was high and had horizontal creases in it that cut in sharply when he raised his eyebrows in contempt.

"Every connection," said Pointdexter. "To construct a time machine is itself a challenge to fate. You make it worse by your flat confidence. How can you be sure that your time-travel machine will operate through all of time without the possibility of paradox?"

Barron said, "I didn't know you were superstitious. The simple fact is that a time machine is a machine like any other machine, no more and no less sacrilegious. Mathematically, it is analogous to an elevator moving up and down its shaft. What danger of retribution lies in that?"

Pointdexter said energetically, "An elevator doesn't involve paradoxes. You can't move from the fifth floor to the fourth and kill your grandfather as a child."

Dr. Barron shook his head in agonized impatience. "I was waiting for that. For exactly that. Why couldn't you suggest that I would meet myself or that I would change history by telling McClellan that Stonewall Jackson was going to make a flank march on Washington, or anything else? Now I'm asking you point blank. Will you come into the machine with me?"

Pointdexter hesitated. "I...I don't think so."

"Why do you make things difficult? I've explained already that time is invariant. If I go into the past it will be because I've already been there. Anything I decided to do and proceed to do. I will have already done in the past all along, so I'll be changing nothing and no paradoxes willresult. If I decided to kill my grandfather as a baby, and did it I would not be here. But I am here. Therefore I did not kill my grandfather. No matter how I try to kill him and plan to kill him, the fact is I didn't kill him and so I won't kill him. Nothing would change that. Do you understand what I'm explaining?"

"I understand what you say, but are you right?"

"Of course I'm right. For God's sake, why couldn't you have been a mathematician instead of a machinist with a college education?" In his impatience, Barron could scarcely hide his contempt. "Look, this machine is only possible because certain mathematical relationships between space and time hold true. You understand that, don't you, even if you don't follow the details of the mathematics? The machine exists, so the mathematical relations I worked out have some correspondence in reality. Right? You've seen me send rabbits a week into the future. You've seen them appear out of nothing. You've watched me send a rabbit a week into the past one week after it appeared. And they were unharmed."

"All right. I admit all that."

"Then will you believe me if I tell you that the equations upon which this machine is based assume that time is composed of particles that exist in an unchanging order; that time is invariant. If the order of the particles could be changed in any way-any way at all-the equations would be invalid and this machine wouldn't work; this particular method of time travel would be impossible."

Pointdexter rubbed his eyes again and looked thoughtful. "I wish I knew mathematics."

Barron said, "Just consider the facts. You tried to send the rabbit two weeks into the past when it had arrived only one week in the past. That would have created a paradox, wouldn't it? But what happened? The indicator stuck at one week and wouldn't budge. You couldn't create a paradox. Will you come?"

Pointdexter shuddered at the edge of the abyss of agreement and drew back. He said, "No."

Barron said, "I wouldn't.ask you to help if I could do this alone, but you know it takes two men to operate the machine for intervals of more than a month. I need someone to control the Standards so that we can return with precision. And you're the one I want to use. We share the-the glory of this thing now. Do you want to thin it out, but in a third person? Time enough for that after we've established ourselves as the first time travelers in history. Good Lord, man, don't you want to see where we'll be a hundred years from now, or a thousand; don't you want to see Napoleon, or Jesus, for that matter? We'll be like-like"-Barron seemed carried away-"like gods."

"Exactly," mumbled Pointdexter. " Hubris. Time travel isn't godlike enough to risk being stranded out of my owntime."

"Hubris. Stranded. You keep making up fears. We're just moving along the particles of time like an elevator along the floors of a building. Time travel is actually safer because an elevator cable can break, whereas in the time machine there'll be no gravity to pun us down destructively. Nothing wrong can possibly happen. I guarantee it," said Barron, tapping his chest with the middle finger of his right hand. "I guarantee it."

"Hubris," muttered Pointdexter, but fell into the abyss of agreement nevertheless, overborne at last.

Together they entered the machine.

Pointdexter did not understand the controls in the sense Barron did, for he was no mathematician, but he knew how they were supposed to be handled.

Barron was at one set, the Propulsions. They supplied the drive that forced the machine along the time axis. Pointdexter was at the Standards that kept the point of origin fixed so that the machine could move back to the original starting point at any time.

Pointdexter's teeth chattered as the first motion made itself felt in his stomach, Like an elevator's motion it was, but not quite, It was something more subtle, yet very real. He said, "What if-"

Barron snapped out, "Nothing can go wrong. Please!" And at once there was a jar and Pointdexter fell heavily against the wall.

Barron said, "What the devil!"

"What happened?" demanded Pointdexter breathlessly. "I don't know, but it doesn't matter. We're only twenty-two hours into the future. Let's step out and check."

The door of the machine slid into its recessed panel and the breath went out of Pointdexter's body in a panting whoosh. He said, "There's nothing there."

Nothing. No matter. No light.