Baley's reverie did not last long. They were standing just inside the main entrance and Daneel had held out his arm to stop the other two. Some thirty seconds passed before Baley, speaking in an automatic whisper in view of the silence everywhere, said, "Why are we waiting?"
"Because it is advisable to do so, Partner Elijah," said Daneel. "There is a tingle field ahead."
"A what?"
"A tingle field, Partner Elijah. Actually, the name is a euphemism. It stimulates the nerve endings and produces a rather sharp pain. Robots can pass, but human beings cannot. Any breach, of course, whether by human or robot, will set off an alarm."
Baley said, "How can you tell there's a tingle field?"
"It can be seen, Partner Elijah, if you know what to look for. The air seems to twinkle a bit and the wall beyond that region has a faint greenish tinge as compared to the wall in front of it."
"I'm not at all sure I see it," said, Baley indignantly. "What's to prevent me - or any innocent outsider - from walking into it and experiencing agony?"
Daneel said, "Those who are members of the Institute carry a neutralizing device; those who are visitors are almost always attended by one or more robots who will surely detect the tingle field."
A robot was approaching down the corridor on the other side of the field. (The twinkling of the field was more easily noted against the muted smoothness of his metallic surface.) He seemed to ignore Giskard, but, for a moment, he hesitated as he looked from Baley to Daneel and back. And - then, having made a decision, he addressed Baley. (Perhaps, thought Baley, Daneel looks too human to be human.)
The robot said, "Your name, sir?"
Baley said, "I am Plainclothesman Elijah Baley from Earth. I am accompanied by two robots of the establishment of Dr. Han Fastolfe - Daneel Olivaw and Giskard Reventlov."
"Identification, sir?"
Giskard's serial number flared out in soft phosphorescence on the left side of his chest. "I vouch for the other two, friend," he said.
The robot studied the number a moment, as though comparing it with a file in his memory banks. Then he nodded and said, "Serial number accepted. You may pass."
Daneel and Giskard moved forward at once, but Baley found himself edging ahead slowly. He put out one arm as a way of testing the coming of pain.
Daneel said, "The field is gone, Partner Elijah. It will be restored after we have passed through."
Better safe than sorry, thought Baley, and continued his shuffle till he was well past the point where the barrier of the field might have existed.
The robots, showing no sign of impatience or condemnation, waited for Baley's reluctant steps to catch up with them.
They then stepped onto a helical ramp, that was only two people wide. The robot was first, by himself; Baley and Daneel stood side by side behind him (Daneel's hand rested lightly, but almost possessively, on Baley's elbow); and Giskard brought up the rear.
Baley was conscious of his shoes pointing upward just a bit uncomfortably and felt vaguely that it would be a little tiresome mounting this too-steep ramp and having to lean forward in order to avoid a clumsy slip. Either the soles of his shoes or the surface of the ramp - or both - ought to be ridged. In fact, neither was.
The robot in the lead said, "Mr. Baley," as though warning of something, and the robot's hand then visibly tightened on the railing that it held.
At once, the ramp divided into sections that slid against each other, to form steps. Immediately thereafter, the whole ramp began to move upward. It made a complete turn, passing up through the ceiling, a section of which had retracted, and, when it came to a halt, they were on what was (presumably) the second floor. The steps disappeared and the four stepped off.
Baley looked back curiously. "I suppose it will service those who want to go down as well, but what if there is a period where more people want to go up than down? It would end up sticking half a kilometer into the sky or into the ground, in reverse."
"That is an up-helix," said Daneel in a low voice. "There are separate down-helices."
"But it has to get down again, doesn't it?"
"It collapses at the top - or the bottom depending on which we're speaking of, Partner Elijah, and, in periods of nonuse, it unwinds, so to speak. This up-helix is descending now."
Baley looked back. The smooth surface might be sliding downward, but it showed no irregularity or mark - whose motion he could notice.
"And if someone should want to use it when it has moved up as far as it can?"
"Then one must wait for the unwinding, which would take less than a minute. - There are ordinary flights of stairs as well, Partner Elijah, and most Aurorans are not reluctant to use them. Robots almost always use the stairs. Since you are a visitor, you are being offered the courtesy of the helix."
They were walking down a corridor again, toward a door more ornate than the others. "They are offering me courtesy, then," said Baley. "A hopeful sign."
It was perhaps another hopeful sign that an Auroran now appeared in the ornate doorway. He was tall, at least eight centimeters taller than Daneel, who was some five centimeters taller than Baley. The man in the doorway was broad as well, somewhat heavyset, with a round face, a somewhat bulbous nose, curly dark hair, a swarthy complexion, and a smile.
It was the smile that was most noticeable. Wide and apparently unforced, it revealed prominent teeth that were white and well-shaped.
He said, "Ah, it - is Mr. Baley, the famous investigator from Earth, who has come to our little planet to show that I am a dreadful villain. Come in, come in. You are welcome. I am sorry if my able aide, Roboticist Maloon Cicis, gave you the impression that I would be unavailable, but he is a cautious fellow and is a great deal more concerned about my time than I myself am."