"Just what is it?"

"Essentially it's a hell of a lot of soft iron surrounded by a hell of a lot more foam plastic, enough to float it, plus a displacement-booth receiver feeding into the iron. Look, see it surge?"

The island rose several feet, slowly, then fell back as slowly. Ripples moved outward and became waves as they reached the station.

"That must have been a big load. Now, here's how it works. You know that the rotation of the Earth puts a limit on how far you can send a load. If you were to shift from here to Rio de Janeiro, say, you'd flick in moving up and sideways-mainly up, because Rio and L.A. are almost the same distance from the equator.

"But with the long-distance booths, the receiver picks up the kinetic energy and shunts it to the United Air Lines velocity damper. That big mass of iron surges up or down or sideways until the water stops it-or someone flicks in from Rio and the damping body stops cold."

Jerryberry thought about it. "What about conservation of rotation? It sounds like you're slowing down the Earth."

"We are. There's nothing sacred about conservation of rotation, except that the energy has to go somewhere. There are pumps to send water through the damper bodies if they get too hot."

Jerryberry pulled out the Minox. "Mind if I take some pictures?"

"No, go ahead."

The Minox was a movie camera, but it would not have the resolution of a press camera. No matter. If he had the time he could comeback. . not that he thought he would. He took shots of the men at work in the station, of Nils Kjerulf with his back to the windows. He shot almost a minute of the great white island itself. He was hoping it would surge; and presently it did, sinking sideways, surging up again. Waves beat at the station. A jet of white steam sprayed from the top of the great white mass.

"Good," he said briskly to himself. He folded the spidery tripod legs and dropped the camera in his pocket. He turned to Kjerulf, who had been watching the proceedings with some amusement. "Mr. Kjerulf, can you tell me anything about traffic control? Is there any?"

"How do you mean? Customs?"

"Not exactly.. but tell me about customs."

"The customs terminal in Los Angeles is at T.W.A. You haven't been out of the country recently? No? Well, any big-city airport has a customs terminal. In a small country there's likely to be just one. If you dial a number outside the country, any country, you wind up in somebody's customs terminal. The booths there don't have dials, you see. You have to cross the customs line to dial out."

"Clever. Are there any restrictions on traffic within the United States?"

"No, you just drop your chocolate dollars in and dial. Unless it's a police matter. If the police know that someone's trying to leave the city they may set up a watch in the terminals. We can put a delay on the terminals to give a detective time to look at a passenger's face and see if he's who they want."

"But nothing to stop passengers from coming in."

"No, except that it's possible to Kjerulf trailed off oddly, then finished, "…turn off any booth by remote control, from the nearest JumpShift maintenance system. What are you thinking of, the mall riot?"

There was no more to say. He left Nils Kjerulf in the United terminal in Los Angeles. He dialed for customs.

For several minutes Jerryberry watched them flicking in. There were two types:

The tourists came in couples, sometimes with a child or two. They flicked in looking interested and harried and a little frightened. Their clothing was outlandish and extraordinary. Before they left the booths, they would look about them mistrustfully. Sometimes they formed larger groups.

The businessmen traveled alone. They wore conservative or old-fashioned clothing and carried one suitcase: large or small, but one. They were older than the tourists. They moved with authority, walking straight out of the booths the moment they appeared.

At the barner: four men in identical dark suits with shield-shaped shoulder patches. Jerryberry was on the wrong side of the barrier to command their attention. He was thinking of dialing himself to Mexico and back when one of them noticed him and pegged him as a newstaper.

His name was Gregory Scheffer. Small and round and middle-aged, he perched on the wooden barner and clasped one knee in both hands. "Sure, I can talk awhile. This isn't one of the busy days. The only time these booths really get a workout is Christmas and New Year and Bastille Day and like that. Look around you," he said, waving a pudgy hand expansively.

"About four times as many incoming as there was six months ago. I used to want to search every bag that came through, just to be doing something. If we keep getting more and more of them this way, we'll need twice as many customs people next year."

"Why do you suppose-"

"Did you know that the long-distance booths have been operating for two solid years? It's only in the last six months or so that we've started to get so many passengers. They had to get used to traveling again. Look around you; look at all this space. It used to be full before JumpShift came along. People have got out of the habit of traveling, that's all there is to it. For twenty solid years. They have to get back into it."

"Guess so." Jerryberry tried to remember why he was here. "Mr. Scheffer-"

"Greg."

"Jerryberry. Customs' main job is to stop smuggling, isn't it?"

"Well. . it used to be. Now we only slow it down, and not very damn much. Nobody in his right mind would smuggle anything through customs. There are safer ways."

"Oh?"

"Diamonds, for instance. Diamonds are practically indestructible. You could rig a cargo booth in Kansas to receive from. . oh, there's a point in the South Pacific to match anyplace in the United States: same longitude, opposite latitude. You don't need a velocity damper if you put the boat in the right place. Diamonds? You could ship in Swiss watches that way. Though that's pretty finicky. You'd want to pad them."

"Good grief. You could smuggle anything you pleased, anywhere."

"Just about. You don't need the ocean trick. Say you rig a booth a mile south of the Canadian border, and another booth a mile north. That's not much of a jump. You can flick further than that just in L.A. I think we're obsolete," said Scheffer. "I think smuggling laws are obsolete. You won't publish this?"

"I won't use your name."

"I guess that's okay."

"Can you get me over to the incoming booths? I want to take some pictures."

"What for?"

"I'm not sure yet."

"Let's see some ID." Gregory Scheffer didn't trust evasive answers. The incoming booths were in his jurisdiction. He studied the C.B.A. card for a few seconds and suddenly said, "Jansen! Mall riot!"

"Right!"

"What was it like?"

Jerryberry invested half a minute telling him. "So now I'm trying to find out how it got started. If there were some way to stop all of those people from pouring in like that-"

"You won't find it here. Look, a dozen passengers and we're almost busy. A thousand people suddenly pour through those booths, and what would we do? Hide under something, that's what we'd do."

"I still want to see the incoming booths."

Scheffer thought it over, shrugged, and let him through. He stood at Jerryberry's shoulder while Jerryberry used his eye and his camera.

The booth was just like a street-corner booth, except for the blank metal face where a dial would be. "I don't know what's underneath," Scheffer told him. "For all of me, it's just like any other booth. How much work would it be to leave off the dial?"

Which made sense. But it was no help at all.