Seldon said in a low voice, “I heard nothing of this back home. Of course, our own news media are terribly local, but you’d think there’d be some mention that this sort of thing exists.”

Hummin said. “It’s strictly experimental and is confined to the Imperial Sector. It uses more energy than it’s worth, so the government is not really anxious to push it right now by giving it publicity. The old Emperor, Stanel VI, the one before Cleon who amazed everyone by dying in his bed, insisted on having it installed in a few places. He wanted his name associated with antigravity, they say, because he was concerned with his place in history, as old men of no great attainments frequently are. As I said, the technique may spread, but, on the other hand, it is possible that nothing much more than the gravitic lift will ever come of it.”

“What do they want to come of it?” asked Seldon.

“Antigrav spaceflight. That, however, will require many breakthroughs and most physicists, as far as I know, are firmly convinced it is out of the question. But, then, most thought that even gravitic lifts were out of the question.”

The line ahead was rapidly growing shorter and Seldon found himself standing with Hummin at the edge of the floor with an open gap before him. The air ahead faintly glittered. Automatically, he reached out his hand and felt a light shock. It didn’t hurt, but he snatched his hand back quickly.

Hummin grunted. “An elementary precaution to prevent anyone walking over the edge before activating the controls.” He punched some numbers on the control board and the glitter vanished.

Seldon peered over the edge, down the deep shaft. “You might find it better-or easier,” said Hummin, “if we link arms and if you close your eyes. It won’t take more than a few seconds.”

He gave Seldon no choice, actually. He took his arm and once again there was no hanging back in that firm grip. Hummin stepped into nothingness and Seldon (who heard himself, to his own embarrassment, emit a small squeak) shuffled off with a lurch.

He closed his eyes tightly and experienced no sense of falling, no feeling of air movement. A few seconds passed and he was pulled forward. He tripped slightly, caught his balance, and found himself on solid ground. He opened his eyes, “Did we make it?”

Hummin said dryly, “We’re not dead,” then walked away, his grip forcing Seldon to follow.

“I mean, did we get to the right level?”

“Of course.”

“What would have happened if we were dropping down and someone else was moving upward?”

“There are two separate lanes. In one lane everyone drops at the same speed; in the other everyone rises at the same speed. The shaft clears only when there are no people within ten meters of each other. There is no chance of a collision if all works well.”

“I didn’t feel a thing.”

“Why should you? There was no acceleration. After the first tenth of a second, you were at constant speed and the air in your immediate vicinity was moving down with you at the same speed.”

“Marvelous.”

“Absolutely. But uneconomic. And there seems no great pressure to increase the efficiency of the procedure and make it worthwhile. Everywhere one hears the same refrain. ‘We can’t do it. It can’t be done.’ It applies to everything.” Hummin shrugged in obvious anger and said, “But we’re here at the taxi rental.

Let’s get on with it.”

Seldon tried to look inconspicuous at the air-taxi rental terminus, which he found difficult. To look ostentatiously inconspicuous-to slink about, to turn his face away from all who passed, to study one of the vehicles overintently-was surely the way to invite attention. The way to behave was merely to assume an innocent normality.

But what was normality? He felt uncomfortable in his clothes. There were no pockets, so he had no place to put his hands. The two pouches, which dangled from his belt on either side, distracted him by hitting against him as he moved, so that he was continually thinking someone had nudged him. He tried looking at women as they passed. They had no pouches, at least none dangling, but they carried little boxlike affairs that they occasionally clipped to one hip or another by some device he could not make out. It was probably pseudomagnetic, he decided. Their clothes were not particularly revealing, he noted regretfully, and not one had any sign of dйcolletage, although some dresses seemed to be designed to emphasize the buttocks. Meanwhile, Hummin had been very businesslike, having presented the necessary credits and returned with the superconductive ceramic tile that would activate a specific air-taxi.

Hummin said, “Get in, Seldon,” gesturing to a small two-seated vehicle.

Seldon asked, “Did you have to sign your name, Hummin?”

“Of course not. They know me here and don’t stand on ceremony.”

“What do they think you’re doing?”

“They didn’t ask and I volunteered no information.” He inserted the tile and Seldon felt a slight vibration as the air-taxi came to life. “We’re headed for D-7,” said Hummin, making conversation.

Seldon didn’t know what D-7 was, but he assumed it meant some route or other. The air-taxi found its way past and around other ground-cars and finally moved onto a smooth upward-slanting track and gained speed. Then it lifted upward with a slight jolt.

Seldon, who had been automatically strapped in by a webbed restraint, felt himself pushed down into his seat and then up against the webbing. He said, “That didn’t feel like antigravity.”

“It wasn’t,” said Hummin. “That was a small jet reaction. Just enough to take us up to the tubes.”

What appeared before them now looked like a cliff patterned with cave openings, much like a checkerboard. Hummin maneuvered toward the D-7 opening, avoiding other air-taxis that were heading for other tunnels.

“You could crash easily,” said Seldon, clearing his throat.

“So I probably would if everything depended on my senses and reactions, but the taxi is computerized and the computer can overrule me without trouble. The same is true for the other taxis.-Here we go.”

They slid into D-7 as if they had been sucked in and the bright light of the open plaza outside mellowed, turning a warmer yellow hue. Hummin released the controls and sat back. He drew a deep breath and said, “Well, that’s one stage successfully carried through. We might have been stopped at the station. In here, we’re fairly safe.”

The ride was smooth and the walls of the tunnel slipped by rapidly. There was almost no sound, just a steady velvety whirr as the taxi sped along. “How fast are we going?” asked Seldon.

Hummin cast an eye briefly at the controls. “Three hundred and fifty kilometers per hour.”

“Magnetic propulsion?”

“Yes. You have it on Helicon, I imagine.”

“Yes. One line. I’ve never been on it myself, though I’ve always meant to. I don’t think it’s anything like this.”

“I’m sure it isn’t. Trantor has many thousands of kilometers of these tunnels honeycombing the land subsurface and a number that snake under the shallower extensions of the ocean. It’s the chief method of long-distance travel.”

“How long will it take us?”

“To reach our immediate destination? A little over five hours.”

“Five hours!” Seldon was dismayed.

“Don’t be disturbed. We pass rest areas every twenty minutes or so where we can stop, pull out of the tunnel, stretch our feet, eat, or relieve ourselves. I’d like to do that as few times as possible, of course.”

They continued on in silence for a while and then Seldon started when a blaze of light flared at their right for a few seconds and, in the flash, he thought he saw two air-taxis.

“That was a rest area,” said Hummin in answer to the unspoken question.