None. The past was unchangeable. It existed only as a memory in his own mind, and there was no way to change that indelible record, even had he wished to do such an insane thing.

Surely, he thought, the real rulers must know of his existence. He had tried, by his every action, to show that he was a reasoning, intelligent, and civilized being. Why had they taken no action?

His hypotheses, he realized, were weak because of lack of data. He could only wait for more information.

That--and continue to work.

VII

INTERLUDE

Mrs. Frobisher touched the control b.u.t.ton that depolarized the window in the breakfast room, letting the morning sun stream in. Then she said, in a low voice, "Larry, come here."

Larry Frobisher looked up from his morning coffee. "What is it, hon?"

"The Stanton boys. Come look."

Frobisher sighed. "Who are the Stanton boys, and why should I come look?"

But he got up and came over to the window.

"See--over there on the walkway toward the play area," she said.

"I see three girls and a boy pushing a wheeled contraption," Frobisher said. "Or do you mean that the Stanford boys are dressed up as girls?"

"_Stanton_," she corrected him. "They just moved into the apartment on the first floor."

"Who? The three girls?"

"No, silly! The two Stanton boys and their mother. One of them is in that 'wheeled contraption'. It's called a therapeutic chair."

"Oh? So the poor kid's been hurt. What's so interesting about that, aside from morbid curiosity?"

The boy pushing the chair went around a bend in the walkway, out of sight, and Frobisher went back to his coffee while his wife spoke.

"Their names are Mart and Bart. They're twins."

"I should think," Frobisher said, applying himself to his breakfast, "that the mother would get a self-powered chair for the boy instead of making the other boy push it."

"The poor boy can't control the chair, dear. Something wrong with his nervous system. I understand that he was exposed to some kind of radiation when he was only two years old. That's why the chair has all the instruments built into it. Even his heartbeat has to be controlled electronically."

"Shame." Frobisher speared a bit of sausage. "Kind of rough on both of 'em, I'd guess."

"How do you mean?"

"Well, I mean, like.... Well, for instance, why are they going over to the play area? Play games, right? The one that's well has to push his brother over there--can't just get out and go; has to take the brother along. Kind of a burden, see?

"And then, the kid in the chair has to sit there and watch his brother play basketball or jai alai, while he can't do anything himself. Like I say, kind of rough on both of them."

"Yes, I suppose it must be. More coffee?"

"Thanks, honey. And another slice of toast, hunh?"

VIII

The two objects floating in s.p.a.ce both looked like pitted pieces of rock.

The larger one, roughly pear-shaped and about a quarter of a mile in its greatest dimension, was actually that--a hunk of rock. The smaller--_much_ smaller--of the two was a camouflaged s.p.a.ceboat. The smaller was on a near-collision course with reference to the larger, although their relative velocities were not great.

At precisely the right time, the smaller drifted by the larger, only a few hundred yards away. The weakness of the gravitational fields generated between the two caused only a slight change of orbit on the part of both bodies. Then they began to separate.

But, during the few seconds of their closest approach, a third body had detached itself from the camouflaged s.p.a.ceboat and shot rapidly across the intervening distance to land on the surface of the floating mountain.

The third body was a man in a s.p.a.cesuit. As soon as he landed, he sat down, stock-still, and checked the instrument case he held in his hands.

No response. Thus far, then, he had succeeded.

He had had to pick his time precisely. The people who were already on this small planetoid could not use their detection equipment while the planetoid itself was within detection range of Beacon 971, only two hundred and eighty miles away. Not if they wanted to keep from being found. Radar pulses emanating from a presumably lifeless planetoid would be a dead giveaway.

Other than that, they were mathematically safe--if they depended on the laws of chance. No ship moving through the Asteroid Belt would dare to move at any decent velocity without using radar, so the people on this particular lump of planetary flotsam would be able to spot a ship's approach easily, long before their own weak detection system would register on the pick-ups of the approaching ship.

The power and range needed by a given detector depends on the relative velocity--the greater that velocity, the more power, the greater range needed. At one mile per second, a ship needs a range of only thirty miles to spot an obstacle thirty seconds away; at ten miles per second, it needs a range of three hundred miles.

The man who called himself Stanley Martin had carefully plotted the orbit of this particular planetoid and then let his s.p.a.ceboat coast in without using any detection equipment except the visual. It had been necessary, but very risky.

Had the people here seen his boat? If so, had they recognized it, in spite of the heavy camouflage? And, even if they only suspected, what would be their reaction?

He waited.

It takes nerve and patience to wait for thirteen solid hours without moving more than an occasional flexure of muscles, but he managed that long before the instrument case waggled a meter needle at him. The one relieving factor was the low gravity; on an asteroid, the problem of sleeping on a bed of nails is caused by the likelihood of accidentally throwing oneself off the bed. The probability of puncture or discomfort from the points is almost negligible.

When the needle on the instrument panel flickered, he got to his feet and began moving. He was almost certain that he had not been detected.

Walking was out of the question. This was a silicate-alumina rock, not a nickel-iron one. The group that occupied it had deliberately chosen it that way, so that there would be no chance of its being picked out for slicing by one of the mining teams in the Asteroid Belt. Granted, the chance of any given metallic planetoid's being selected was very small, they had not even wanted to take that chance. Therefore, without any magnetic field to hold him down, and only a very tiny gravitic field, the man had to use different tactics.

It was more like mountain climbing than anything else, except that there was no danger of falling. He crawled over the surface in the same way that an Alpine climber might crawl up the side of a steep slope--seeking handholds and toeholds and using them to propel himself onward. The only difference was that he covered distance a great deal more rapidly than a mountain climber could.

When he reached the spot he wanted, he carefully concealed himself beneath a craggy overhang. It took a little searching to find exactly the right spot, but when he did, he settled himself into place in a small pit and began more elaborate preparations.

Self-hypnosis required nearly ten minutes. The first five or six minutes were taken up in relaxing from his exertion. Gravity notwithstanding, he had had to push his hundred and eighty pounds of ma.s.s over a considerable distance. When he was completely relaxed and completely hypnotized, he reached up and cut down the valve that fed oxygen into his suit.

Then, of his own will, he went cataleptic.

A single note, sounded by the instruments in the case by his side, woke him instantly. He came fully awake, as he had commanded himself to do.

Immediately, he turned up his oxygen intake, at the same time glancing at the clock dial in his helmet. He smiled. Nineteen days and seven hours. He had calculated it almost precisely. He wasn't more than an hour off, which was pretty good, all things considered.