Ken Maddox could not remember a time when he had not wanted to become a scientist. Maybe it started when his father first invited him to look through a microscope. That was when he was a very small boy, but he could still remember the revelation of that experience. He remembered how it had seemed, on looking away from the lens, that the whole world of normal vision was only a fragment of that which was hidden behind curtains and shrouds and locked doors. Only men, like his father, with special instruments and wisdom and knowledge, could ever hope to understand the world of the unknown, which the ordinary person did not even suspect.

Now, at sixteen, Ken was tall, with black hair that had an annoying curl to it. He was husky enough to be the main asset of the football squad of Mayfield High School in his senior year. He knew exactly where he was going and what he was going to do. He would be one of those men who lived beyond the mere surface of the world, and who would seek to understand its deep and hidden meanings.

Ken thought of this as he watched Maria at the telescope. What a difference between knowing the comet as this instrument showed it, and with the knowledge revealed by modern astronomy, and knowing it as the average person in Mayfield did.

Ken and Maria stayed in the observatory until the comet had almost disappeared below the horizon. Mrs. Maddox brought a snack of sandwiches and punch.

"I always do this when I see the observatory dome open," she said, smiling. "I never know when Ken's going to quit his stargazing and come in for the night."

"We're about through, Mom. I'll drive Maria over to her place and be back in a little while."

"I'm going to loan him the stamps," Maria said.

Mrs. Maddox looked at Ken in mock severity. "You mean you forgot again?"

"No—I remembered," Ken said lamely. "After the post office closed, that is. Anyhow, Maria has plenty."

"Well," said Mrs. Maddox, "I know who's going to have to mail my invitations if they're ever to get out in time for the party!"

After he and Maria had finished the snack, Ken started his car again. The engine had cooled to normal temperature, but he watched the indicator closely as he drove. Nothing seemed right about the action of the car. The engine had turned over sluggishly when he pressed the starter button, as if the battery were almost dead. Now it lugged heavily, even when going downhill.

"The whole thing's haywire," Ken said irritably. "It acts like the crankcase is full of sand or something."

"Let me walk the rest of the way," said Maria. "You take the car back, and I'll bring the stamps over on my way to school in the morning."

"No, we're almost there. Nothing much more could go wrong than already has."

When they reached Maria's place they found Professor and Mrs. Larsen sitting on the porch.

"We've been watching the comet," Maria said excitedly. "Ken let me look at it through his telescope."

"A remarkable event," said Professor Larsen. "I feel very fortunate to be alive to witness it. My generation hasn't had this kind of privilege before. I was a child when Halley's comet appeared."

"I've been trying to tell Maria what a lucky break this is, but she agrees with Granny Wicks," said Ken.

"Oh, I do not!" Maria snapped.

"Granny Wicks?" Professor Larsen inquired. "Your grandmother?"

"No." Ken tried to cover the professor's lack of familiarity with American idioms. "She's just the town's oldest citizen. Everybody likes her and calls her Granny, but her mind belongs to the Middle Ages."

"You hear that, Papa?" cried Maria. "Her mind belongs to the Middle Ages, and he says I'm like Granny Wicks!"

Maria's mother laughed gently. "I'm sure Ken didn't mean your mind is of the Middle Ages, too, dear."

Ken flushed. "Of course not. What I mean is that Granny Wicks thinks the comet is something mysterious and full of omens, and Maria says she sort of thinks the same about it."

"I didn't say anything about omens and signs!"

"Well, except for that...."

"Except for that, I suppose we are all in agreement," said Professor Larsen slowly. He drew on his pipe and it glowed brightly in the darkness. "The whole universe is a terrible place that barely tolerates living organisms. Almost without exception it is filled with great suns that are flaming, atomic furnaces, or dead cinders of planets to which a scrap of poisonous atmosphere may cling. Yes, it is indeed a great miracle that here in this corner of the universe conditions exist where living things have found a foothold. We may be glad that this is so, but it does not pay man to ever forget the fierceness of the home in which he lives. Earth is merely one room of that home, on the pleasant, sunny side of the house. But the whole universe is his home."

"That's the thing I've been trying to say," Ken answered. "We can know this without being afraid."

Maria's father nodded. "Yes. Fear is of no use to anyone. Awe, respect, admiration, wonder, humility—these are all necessary. But not fear."

Maria turned from the group. "I'll bring the stamps, Ken," she said.

"Won't you come in and have some cake?" Mrs. Larsen asked.

"No, thanks. Mother fed us before we left my place. I'm afraid I couldn't eat any more."

In a moment Maria was back. "Here are two whole sheets," she said. "I hope that will be enough."

"Plenty. I'll see you get repaid tomorrow. Good night, everybody."

"Good night, Ken."

He moved down the walk toward his car and got in. When he pressed die starter button the engine groaned for a few seconds and came to a complete stop. He tried again; there was only a momentary, protesting grind.

Ken got out and raised the hood and leaned over the engine in disgusted contemplation. There was no visible clue to the cause of the trouble.

"Is your battery dead?" Professor Larsen called.

"No. It's something else." Ken slammed the hood harder than he had intended. "I'll have to leave it here overnight and pick it up in the morning."

"I can push you home with my car, or at least give you a ride."

"No, please don't bother," Ken said. "I'll tow it home with Dad's car tomorrow. I'd just as soon walk, now. It's only a few blocks."

"As you wish. Good night, Ken."

"Good night, Professor."

Ken's clock radio woke him the next morning. He reached over to shut off the newscast it carried. There was only one item any commentator talked about now, the comet. Ken wondered how they could get away with a repetition of the same thing, over and over, but they seemed able to get an audience as long as they kept the proper tone of semi-hysteria in their voices.

As his hand touched the dial to switch it off, something new caught Ken's attention. "A curious story is coming in from all parts of the country this morning," the announcer said. "Auto mechanics are reporting a sudden, unusually brisk business. No one knows the reason, but there seems to be a virtual epidemic of car breakdowns. Some garagemen are said to be blaming new additives in gasoline and lubricating oil. It is reported that one major oil company is undertaking an investigation of these charges, but, in the meantime, no one really seems to have a good answer.

"In connection with the comet, however, from widely scattered areas comes the report that people are even blaming these engine failures on our poor, old comet. In the Middle Ages they blamed comets for everything from soured cream to fallen kingdoms. Maybe this modern age isn't so different, after all. At any rate, this comet will no doubt be happy to get back into open space, where there are no Earthmen to blame it for all their accidents and shortcomings!"

Ken switched off the radio and lay back on the pillow. That was a real choice one—blaming the comet for car breakdowns! Page Granny Wicks!

The breakdowns were curious, however. There was no good reason why there should be a sudden rash of them. He wondered if they had actually occurred, or if the story was just the work of some reporter trying to make something out of his own inability to get into a couple of garages that were swamped by the usual weekend rush. This was most likely the case.

However it didn't explain why his own car had suddenly conked out, Ken thought irritably. He'd have to get it over to Art Matthews' garage as soon as school was out.

At school that morning there was little talk of anything but the comet. After physics class, Ken was met by Joe Walton and three other members of the science club, of which Ken was president.

"We want a special meeting," said Joe. "We've just had the most brilliant brainstorm of our brief careers."

"It had better be more brilliant than the last one," said Ken. "That drained the club treasury of its last peso."

"I was watching the comet last night, and I began to smell the dust of its tail as the Earth moved into it...."

"You must have been smelling something a lot more powerful than comet dust."

"I said to myself—why don't we collect some of that stuff and bottle it and see what it's made of? What do you think?" Joe asked eagerly.

Ken scowled. "Just how many molecules of material from the comet's tail do you think there are in the atmosphere over Mayfield right now?"

"How do I know? Six—maybe eight."

Ken laughed. "You're crazy, anyway. What have you got in mind?"

"I'm not sure," Joe answered seriously. "We know the comet's tail is so rarefied that it resembles a pretty fair vacuum, but it is composed of something. As it mixes with the atmosphere we ought to be able to determine the changing makeup of the air and get a pretty good idea of the composition of the comet's tail. This is a chance nobody's ever had before—and maybe never will again, until we go right out there in spaceships—being right inside a comet's tail long enough to analyze it!"

"It sounds like a terrific project," Ken admitted. "The universities will all be doing it, of course, but it would still be a neat trick if we could bring it off. Maybe Dad and Professor Larsen will have ideas on how we could do it."

"We ought to be able to make most of the equipment," said Joe, "so it shouldn't be too expensive. Anyway, we'll have a meeting then, right after school?"

"Yes—no, wait. The engine in my car conked out. I've got to go over to Art's with it this afternoon. You go ahead without me. Kick the idea around and let me know what's decided. I'll go along with anything short of mortgaging the football field."

"Okay," said Joe. "I don't see why you don't just sell that hunk of junk and get a real automobile. You've got a good excuse now. This breakdown is a good omen!"

"Don't talk to me about omens!"

Art Matthews had the best equipped garage in town, and was a sort of unofficial godfather to all the hot-rodders in the county. He helped them plane the heads of their cars. He got their special cams and carburetor and manifold assemblies wholesale, and he gave them fatherly advice about using their heads when they were behind the wheel.

Ken called him at noon. "I've got troubles, Art," he said. "Can I bring the car over after school?"

"I'm afraid I can't do a thing for you today," Art Matthews said. "I don't know what's happened, but I've had tow calls all day. Right now the shop is full and they're stacked four-high outside. I'm going to do a couple of highway patrol cars and Doc Adams'. I figured they ought to have priority."

Ken felt a sudden, uneasy sense of recognition. This was the same kind of thing he had heard about on the radio that morning! A rash of car breakdowns all over the country. Now, the same thing in Mayfield!

"What's wrong with them?" he asked the mechanic. "Why is everybody coming in with trouble at the same time?"

"They're not coming in," said Art. "I'm having to go out after them. I don't know yet what's wrong. They heat up and stall. It's the craziest thing I've run into in 30 years of garage work."

"Mine acted the same way," Ken said.

"Yeah? Well, you're in good company. Listen, why don't you and maybe Joe and Al come down and give me a hand after school? I'll never get on top here without some help. After we get these police and other priority cars out of the way, maybe we can get a quick look at what's wrong with yours."

"It's a deal."

Joe Walton wasn't much in favor of spending that afternoon and an unknown number of others in Art's garage; he was too overwhelmed by the idea of analyzing the material of the comet's tail. However Art had done all of them too many favors in the past to ignore his call for help.

"The trouble with this town," Joe said, "is that three-fourths of the so-called automobiles running around the streets belong down at Thompson's Auto Wrecking."

Al Miner agreed to come, too. When they reached the garage after school they saw Art had not been exaggerating. His place was surrounded by stalled cars, and the street outside was lined with them in both directions. Ken borrowed the tow truck and brought his own car back from the Larsens'. By that time the other two boys were at work.

"Batteries are all okay," Art told him. "Some of these engines will turn over, but most of them won't budge. I've jerked a couple of heads, but I can't see anything. I want you to take the pans off and take down the bearings to see if they're frozen. That's what they act like. When that's done, we'll take it from there."

Ken hoisted the front end of one of the police cars and slid under it on a creeper. Art's electric impact wrenches were all in use, so he began the laborious removal of the pan bolts by hand. He had scarcely started when he heard a yell from Joe who was beneath the other police car.

"What's the matter?" Art called.

"Come here! Look at this!"

The others crowded around, peering under the car. Joe banged and pried at one of the bearings, still clinging to the crankshaft after the cap had been removed.

"Don't do that!" Art shouted at him. "You'll jimmy up the crankshaft!"

"Mr. Matthews," Joe said solemnly, "this here crankshaft has been jimmied up just as much as it's ever going to get jimmied. These bearings are welded solid. They'll have to be machined off!"

"Nothing could freeze them to the shaft that hard," Art exclaimed.

Joe moved out of the way. Art crawled under and tapped the bearing. He pried at it with a chisel. Then he applied a cold chisel and pounded. The bearing metal came away chip by chip, but the bulk of it clung to the shaft as if welded.

"I've never seen anything like that before in my life!" Art came out from beneath the car.

"What do you think could cause it?" Joe asked.

"Gas!" said Art vehemently. "The awful gas they're putting out these days. They put everything into it except sulphur and molasses, and they expect an engine to run. Additives, they call 'em! Detergents! Why can't they sell us plain old gasoline?"

Ken watched from a distance behind the group. He looked at the silent, motionless cars in uneasy speculation. He recalled again the radio announcement of that morning. Maybe it could be something they were adding to the gas or oil, as Art said. It couldn't, however, happen so suddenly—not all over the country. Not in New York, Montgomery, Alabama, San Francisco, and Mayfield. Not all at the same time.

Art turned up the shop lights. Outside, as the sun lowered in the sky, the glow of the comet began turning the landscape a copper-yellow hue. Its light came through the broad doors of the garage and spread over the half-dismantled cars.

"All right, let's go," said Art. His voice held a kind of false cheeriness, as if something far beyond his comprehension had passed before him and he was at a loss to meet it or even understand it.

"Let's go," he said again. "Loosen all those connecting rods and get the shafts out. We'll see what happens when we try to pull the pistons."