"It seems to me you are talking about the thing having a rock-like skin," said Porter.

"In layman language, that is what I am talking about," said Allen. "Hard as rock, probably much harder, and yet the silicon provides it with some elasticity, some give. Rocks can't normally be dented. This stuff can. It can be dented and then bounces back. It has at once hardness and ductility and an incredible thermal stability.

"We have theorized the use to which these capabilities can be put. It is only a theory, of course, but it does make sense. If these things operate across vast extents of interstellar space, they would have to get energy from somewhere. Their high thermal stability means they could soak up all sorts of energy, a lot of it, perhaps, from the impact of interstellar dust. The dust particles, no matter how small, would carry some energy. But in the form of kinetic energy. We think the skins of these things can convert the kinetic energy to potential energy, possibly can change that energy to whatever form it needs. Occasionally, they might collide with larger pieces of matter. Such a strike would indent the skin, with the skin picking up as much energy as it could handle, deflecting what it can't use when the indentation in the skin bounces back, in effect rejecting that part of the energy it can't handle. The dent in the skin would produce a reflected wave of energy, getting rid of it as the surface of a mirror would reflect sunlight."

Porter sneaked a quick look at Whiteside. The general had stiffened in his chair and wore a slightly slack-jawed appearance.

Allen sighed. "We also have some reason to believe," he said, "and I can't go into this as closely as I would like, for it can't be explained in layman terms—but we have reason to believe that the skin's composition is such that it can change gravitational flux and thus points to the possibility that the creatures can manipulate gravitational forces, that they can either be attracted or repulsed by gravitation. Which would explain, if true, how they are able to float an inch or two off the ground. It might also mean that gravitational control may be, at least partially, an explanation of how they travel through space. Locked in on a gravitational source in the direction in which they want to travel, they would move toward the source. Locked into another behind them, they could utilize it as a repulsor to push them away from that ~‘

Allen ceased talking and looked at each of the three in turn.

"Well, that's it," he said. "It sounds insane and I keep telling myself it has to be insane. Aliens, we said. And these things are alien. What bothers me, what keeps me awake at night is this—if they are so alien in the physical sense, how alien are they mentally? What chance will we ever have of understanding them, what hope they will ever be able to understand us?"

"Perhaps the intellectual span is not as great as the physical span," said Porter. "They seem to have done a fairly good job so far in understanding us. Somehow they seem to have sensed a lot

of things they should not do. They have fairly well kept within the basic rules of human conduct."

"I hope you're right," said Allen. "I sincerely hope you are."

He spoke to the President. "In a couple of weeks, we may know more. We may find that some of our present thinking is wrong. We may have to modify some of our theories. Or we may come across some new and significant data. For the present, I have told you basically all I know. Of course, it could be elaborated upon endlessly, but there's no point in doing that now."

He rose from his chair, hesitated for a moment.

"There is one other thing," he said. "Interesting, but probably not too significant. But it does throw some further light on the visitors. You have heard of 101, of course."

The President nodded. "The first of the visitors to land at Lone Pine. I understand it's down in Iowa now.

"That is right," said Allen. "It is guarding a field the farmer had just finished plowing. The farmer claims that it passed back and forth over the field as if it were planting something. When anyone approaches, it drives them off. One of our observers, however, managed to sneak up to the edge of the field without being driven off. He found that the visitor had planted pine seeds. Earlier we had been somewhat puzzled by the fact that the debris which was rejected by the visitors after they cut the trees contained virtually no pine seeds. Now we know why. The visitors winnow out the seeds and intend to plant them."

"It will take a long time to grow a new crop of pines from scratch," said the President. "101 may have its work cut out for it guarding its planting."

"Perhaps not," said Allen. "Our observer found that a number of the seeds had sprouted. Forestry experts tell us that such sprouting could not be expected this quickly. Our guess is that 101 treated the seeds in some way to speed up the sprouting process, probably to speed up the growth once they have started."

"Which poses another problem for us," said Whiteside. "Hundreds, if not thousands, of visitors taking over fields, planting them and then driving off the rightful owners. The farmers will be up in arms about that."

"To start with," said the President, "I had a queasy feeling about the visitors, a sort of gone-in-the-gut reaction. I think part of this, maybe all of it, was due to the fact that essentially I am a pure and simple political animal. I have political nerve endings. I twitch at every threat. I still realize that this business of the visitors, if I make one wrong move, could kill me politically. But, gradually, I have come to the belief that the two of us, we and the visitors, can get along together. They seem to think very much like us. If we could only communicate with them, I'm sure a solid understanding could be reached. The fact that 101 planted pine seeds re-enforces my thinking. The planting of a crop attests to a feeling for agriculture and the conservation of resources. In this way, too, their thinking parallels ours.

Allen started to speak, then hesitated.

"You were about to say something," said the President.

"That's right," said Allen. "I wondered if I should, but I guess there's no reason that I shouldn't. Perhaps of little significance, but to me intriguing. You remember when that first visitor came down at Lone Pine it landed on a car and crushed it."

"Yes, I do remember. There was no one in it, luckily. We wondered what became of the owner, why he, or she, never came forward."

"Exactly," said Allen. "We hauled in the car, if you recall."

"Yes, I do," said the President.

"Well, now we know. From the license plate. The owner is a young forestry student at the University of Minnesota. His name is Jerry Conklin. A few days after the incident, he came back to Minneapolis. So far as we can learn, he never told anyone about his car being totaled. He has not filed an insurance claim for the loss of the car. For a time, apparently, he acted fairly normally, but now that we have learned who he is, he has disappeared. The FBI is looking for him."

"What do you expect to learn when you find him?" Whiteside asked.

"I don't really know. You have to admit, however, that his reaction has been strange. There must be some reason he told no one what happened. And it's strange that he has not filed an insurance claim. He has not even made an inquiry as to who hauled away his car. I can't get rid of the feeling that he may know something that could be helpful to us."

"When you find him," said the President, "and I suppose you will, go easy on him. From where I sit he's committed no crime except to keep his mouth shut."