they traveled along walkways where the light was soft and yellow. hummins eyes moved this way and that, watchful, and he kept their pace at crowd speed, neither passing nor being passed.

he kept up a mild but steady conversation on indifferent topics. seldon, edgy and unable to do the same, said, "there seems to be a great deal of walking here. there are endless lines in both directions and along the crossovers."

"why not?" said hummin. "walking is still the best form of short-distance transportation. its the most convenient, the cheapest, and the most healthful. countless years of technological advance have not changed that.--are you acrophobic, seldon?"

seldon looked over the railing on his right into a deep declivity that separated the two walking lanes--each in an opposite direction between the regularly spaced crossovers. he shuddered slightly. "if you mean fear of heights, not ordinarily. still, looking down isnt pleasant. how far does it go down?"

"forty or fifty levels at this point, i think. this sort of thing is common in the imperial sector and a few other highly developed regions. in most places, one walks at what might be considered ground level."

"i should imagine this would encourage suicide attempts."

"not often. there are far easier methods. besides, suicide is not a matter of social obloquy on trantor. one can end ones life by various recognized methods in centers that exist for the purpose--if one is willing to go through some psychotherapy at first. there are, occasional accidents, for that matter, but thats not why i was asking about acrophobia. were heading for a taxi rental where they know me as a journalist. ive done favors for them occasionally and sometimes they do favors for me in return. theyll forget to record me and wont notice that i have a companion. of course, ill have to pay a premium and, again of course, if demerzels people lean on them hard enough, theyll have to tell the truth and put it down to slovenly accounting, but that may take considerable time."

"where does the acrophobia come in?"

"well, we can get there a lot faster if we use a gravitic lift. not many people use it and i must tell you that im not overjoyed at the idea myself, but if you think you can handle it, we had better."

"whats a gravitic lift?"

"its experimental. the time may come when it will be widespread over trantor, provided it becomes psychologically acceptable--or can be made so to enough people. then, maybe, it will spread to other worlds too. its an elevator shaft without an elevator cab, so to speak. we just step into empty space and drop slowly--or rise slowly--under the influence of antigravity. its about the only application of antigravity thats been established so far, largely because its the simplest possible application."

"what happens if the power blinks out while were in transit?"

"exactly what you would think. we fall and--unless were quite near the bottom to begin with--we die. i havent heard of it happening yet and, believe me, if it had happened i would know. we might not be able to give out the news for security reasons--thats the excuse they always advance for hiding bad news--but i would know. its just up ahead. if you cant manage it, we wont do it, but the corridors are slow and tedious and many find them nauseating after a while." hummin turned down a crossover and into a large recess where a line of men and women were waiting, one or two with children.

seldon said in a low voice, "i heard nothing of this back home. of course, our own news media are terribly local, but youd think thered be some mention that this sort of thing exists."

hummin said. "its strictly experimental and is confined to the imperial sector. it uses more energy than its 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 didnt 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 wont 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, "were 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 didnt 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 cant do it. it cant be done. it applies to everything." hummin shrugged in obvious anger and said, "but were here at the taxi rental.

lets get on with it."