"You look. Humor the old man. Then let's go."

The bearded man—he called himself Professor Garet—went off with the fireman. Don followed them. They had tramped a quarter of a mile along the gravel when the fireman stopped. "Okay," he said "where's the edge? I don't see nothing." The tracks seemed to stretch forever into the darkness.

"It's another half mile or so," the professor said.

"Well, let's hurry up. We haven't got all night."

The old man chuckled. "I'm afraid you have."

They came to it at last, stopping well back from it. Professor Garet swelled with pride, it seemed, as he made a theatrical gesture.

"Behold," he said. "Something even Columbus couldn't find. The edge of the world."

True, everything seemed to stop, and they could see stars shining low on the horizon where stars could not properly be expected to be seen.

Don Cort and the fireman walked cautiously toward the edge while the professor ambled ahead with the familiarity of one who had been there before. But there was a wind and they did not venture too close. Nevertheless, Don could see that it apparently was a neat, sharp edge, not one of your old ragged, random edges such as might have been caused by an explosion. This one had the feeling of design behind it.

Standing on tiptoe and repressing a touch of giddiness, Don looked over the edge. He didn't have to stand on tiptoe any more than he had to sit on the edge of his seat during the exciting part of a movie, but the situation seemed to call for it. Over the edge could be seen a big section of Ohio. At least he supposed it was Ohio.

Don looked at the fireman, who had an unbelieving expression on his face, then at the bearded old man, who was smiling and nodding.

"You see what I mean," he said. "You would have gone right over. I believe you would have had a two-mile fall."

"Of course you could have stayed aboard the train," the man driving the old Pontiac said, "but I really think you'll be more comfortable at Cavalier."

Don Cort, sitting in the back seat of the car with the redhead from the club car, asked, "Cavalier?"

"The college. The institute, really; it's not accredited. What did you say your name was, miss?"

"Jen Jervis," she said. "Geneva Jervis, formally."

"Miss Jervis. I'm Civek. You know Mr. Cort, I suppose."

The girl smiled sideways. "We have a nodding acquaintance." Don nodded and grinned.

"There's plenty of room in the dormitories," Civek said. "People don't exactly pound on the gates and scream to be admitted to Cavalier."

"Are you connected with the college?" Don asked.

"Me? No. I'm the mayor of Superior. The old town's really come up in the world, hasn't it?"

"Overnight," Geneva Jervis said. "If what Mr. Cort and the fireman say is true. I haven't seen the edge myself."

"You'll have a better chance to look at it in the morning," the mayor said, "if we don't settle back in the meantime."

"Was there any sort of explosion?" Don asked.

"No. There wasn't any sensation at all, as far as I noticed. I was watching the late show—or trying to. My house is down in a hollow and reception isn't very good, especially with old English movies. Well, all of a sudden the picture sharpened up and I could see just as plain. Then the phone rang and it was Professor Garet."

"The old fellow with the whiskers and the riding boots?" Jen Jervis asked.

"Yes. Osbert Garet, Professor of Magnology at the Cavalier Institute of Applied Sciences."

"Professor of what?"

"Magnology. As I say, the school isn't accredited. Well, Professor Garet telephoned and said, 'Hector'—that's my name, Hector Civek—'everything's up in the air.' He was having his little joke, of course. I said, 'What?' and then he told me."

"Told you what?" Jen Jervis asked. "I mean, does he have any theory about it?"

"He has a theory about everything. I think what he was trying to convey was that this—this levitation confirmed his magnology principle."

"What's that?" Don asked.

"I haven't the faintest idea. I'm a politician, not a scientist. Professor Garet went on about it for a while, on the telephone, about magnetism and gravity, but I think he was only calling as a courtesy, so the mayor wouldn't look foolish the next morning, not knowing his town had flown the coop."

"What's the population of Superior?"

"Three thousand, including the students at the institute. Three thousand and forty, counting you people from the train. I guess you'll be with us for a while."

"What do you mean by that?" Jen Jervis asked.

"Well, I don't see how you can get down. Do you?"

"Does Superior have an airport?" Don asked. "I've got to get back to—to Earth." It sounded odd to put it that way.

"Nope," Civek said. "No airport. No place for a plane to land, either."

"Maybe not a plane," Don said, "but a helicopter could land just about anywhere."

"No helicopters here, either."

"Maybe not. But I'll bet they're swarming all over you by morning."

"Hm," said Hector Civek. Don couldn't quite catch his expression in the rearview mirror. "I suppose they could, at that. Well, here's Cavalier. You go right in that door, where the others are going. There's Professor Garet. I've got to see him—excuse me."

The mayor was off across the campus. Don looked at Geneva Jervis, who was frowning. "Are you thinking," he asked, "that Mayor Civek was perhaps just a little less than completely honest with us?"

"I'm thinking," she said, "that I should have stayed with Aunt Hattie another night, then taken a plane to Washington."

"Washington?" Don said. "That's where I'm going. I mean where I was going before Superior became airborne. What do you do in Washington, Miss Jervis?"

"I work for the Government. Doesn't everybody?"

"Not everybody. Me, for instance."

"No?" she said. "Judging by that satchel you're handcuffed to, I'd have thought you were a courier for the Pentagon. Or maybe State."

He laughed quickly and loudly because she was getting uncomfortably close. "Oh, no. Nothing so glamorous. I'm a messenger for the Riggs National Bank, that's all. Where do you work?"

"I'm with Senator Bobby Thebold, S.O.B."

Don laughed again. "He sure is."

"Mister Cort!" she said, annoyed. "You know as well as I do that S.O.B. stands for Senate Office Building. I'm his secretary."

"I'm sorry. We'd better get out and find a place to sleep. It's getting late."

"Places to sleep," she corrected. She looked angry.

"Of course," Don said, puzzled by her emphasis. "Come on. Where they put you, you'll probably be surrounded by co-eds, even if I could get out of this cuff."

He took her bag in his free hand and they were met by a gray-haired woman who introduced herself as Mrs. Garet. "We'll try to make you comfortable," she said. "What a night, eh? The professor is simply beside himself. We haven't had so much excitement since the cosmolineator blew up."

They had a glimpse of the professor, still in his CD helmet, going around a corner, gesticulating wildly to someone wearing a white laboratory smock.

II

Don Cort had slept, but not well. He had tried to fold the brief case to pull it through his sleeve so he could take his coat off, but whatever was inside the brief case was too big. Cavalier had given him a room to himself at one end of a dormitory and he'd taken his pants off but had had to sleep with his coat and shirt on. He got up, feeling gritty, and did what little dressing was necessary.

It was eight o'clock, according to the watch on the unhandcuffed wrist, and things were going on. He had a view of the campus from his window. A bright sun shone on young people moving generally toward a squat building, and other people going in random directions. The first were students going to breakfast, he supposed, and the others were faculty