"You are joking."

"No, I'm not! Maybe the life forms I mentioned don't have such involved ideas. My point is: if they did, or do, we'd never guess it. I don't think X conceives of the human race as intelligent."

Bill chewed this for a while, then added: "Where do you think they came from, Doc? Mars, maybe? Or clear out of the Solar System?"

"Not necessarily. Not even probably. It's my guess that they came from the same place we did-from up out of the slime of this planet."

"Really, Doc-"

"I mean it. And don't give me that funny look. I may be sick, but I'm not balmy. Creation took eight days!"

"Huh?"

"I'm using biblical language. 'And God blessed them, and God said unto them, Be fruitful and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.' And so it came to pass. But nobody mentioned the stratosphere."

"Doc-are you sure you feel all right?"

"Dammit-quit trying to psychoanalyze me! I'll drop the allegory. What I mean is: We aren't the latest nor the highest stage in evolution. First the oceans were populated. Then lungfish to amphibian, and so on up, until the continents were populated, and, in time, man ruled the surface of the earth-or thought he did. But did evolution stop there? I think not. Consider-from a fish's point of view air is a hard vacuum. From our point of view the upper reaches of the atmosphere, sixty, seventy, maybe a hundred thousand feet up seem like a vacuum and unfit to sustain life. But it's not vacuum. It's thin, yes, but there is matter there and radiant energy. Why not life, intelligent life, highly evolved as it would have to be-but evolved from the same ancestry as ourselves and fish? We wouldn't see it happen; man hasn't been aware, in a scientific sense, that long. When our grand-daddies were swinging in the trees, it had already happened."

Eisenberg took a deep breath. "Just wait a minute, Doc. I'm not disputing the theoretical possibility of your thesis, but it seems to me it is out on direct evidence alone. We've never seen them, had no direct evidence of them. At least, not until lately. And we should have seen them."

"Not necessarily. Do ants see men? I doubt it."

"Yes-but, consarn it, a man has better eyes than an ant."

"Better eyes for what? For his own needs. Suppose the X-creatures are too high up, or too tenuous, or too fast-moving! for us to notice them. Even a thing as big and as solid and as slow as an airplane can go up high enough to go out of sight, even on a clear day. If X is tenuous and even semitransparent, we never would see them-not even as occultations of stars, or shadows against the moon-though as a matter of fact there have been some very strange stories of just that sort of thing."

Eisenberg got up and stomped up and down. "Do you mean to suggest," he demanded, "that creatures so insubstantial they can float in a soft vacuum built the Pillars?"

"Why not? Try explaining how a half-finished, naked embryo like homo sapiens built the Empire State Building."

Bill shook his head. "I don't get it."

"You don't try. Where do you think this came from? Graves held up one of the miraculous little water spheres.

"My guess is that life on this planet is split three ways, with almost no intercourse between the three. Ocean culture, Ian culture, and another-call it stratoculture. Maybe a fourth down under the crust-but we don't know. We know a little about life under the sea, because we are curious. But how much do they know of us? Do a few dozen bathysphere descents constitute an invasion? A fish that sees our bathysphere might go home and take to his bed with a sick headache, but he wouldn't talk about it, and he wouldn't be believed if he did. If a lot of fish see us and swear out affidavits, along comes a fish-psychologist and explains it as mass hallucination.

"No, it takes something at least as large and solid and permanent as the Pillars to have any effect on orthodox conceptions. Casual visitations have no real effect."

Eisenberg let his thoughts simmer for some time before commenting further. When he did, it was half to himself. "I don't believe it. I won't believe it!"

"Believe what?"

"Your theory. Look, Doc-if you are right, don't you see what it means? We're helpless, we're outclassed."

"I don't think they will bother much with human beings. They haven't, up till now."

"But that isn't it. Don't you see? We've had some dignity as a race. We've striven and accomplished things. Even when we failed, we had the tragic satisfaction of knowing that we were, nevertheless, superior and more able than the other animals. We've had faith in the race-we would accomplish great things yet. But if we are just one of the lower animals ourselves, what does our great work amount to? Me, I couldn't go on pretending to be a 'scientist' if I thought I was just a fish, mucking around in the bottom of a pool. My work wouldn't signify anything."

"Maybe it doesn't."

"No, maybe it doesn't." Eisenberg got up and paced the constricted area of their prison. "Maybe not. But I won't surrender to it. I won't! Maybe you're right. Maybe you're wrong. It doesn't seem to matter very much where the X people came from. One way or the other, they are a threat to our own kind. Doc, we've got to get out of here and warn them!"

"How?"

Graves was comatose a large part of the time before he died. Bill maintained an almost continuous watch over him, catching only occasional cat naps. There was little he could do for his friend, even though he did watch over him, but the spirit behind it was comfort to them both.

But he was dozing when Graves called his name. He woke at once, though the sound was a bare whisper. "Yes, Doc?"

"I can't talk much more, son. Thanks for taking care of me."

"Shucks, Doc."

"Don't forget what you're here for. Some day you'll get a break. Be ready for it and don't muff it. People have to be warned."

"I'll do it, Doc. I swear it."

"Good boy." And then, almost inaudibly, "G'night, son."

Eisenberg watched over the body until it was quite cold and had begun to stiffen. Then, exhausted by his long vigil and emotionally drained, he collapsed into a deep sleep.

When he woke up the body was gone.

It was hard to maintain his morale, after Graves was gone. It was all very well to resolve to warn the rest of mankind at the first possible chance, but there was the endless monotony to contend with. He had not even the relief from boredom afforded the condemned prisoner-the checking off of limited days. Even his "calendar" was nothing but a counting of his sleeps.

He was not quite sane much of the time, and it was the twice-tragic insanity of intelligence, aware of its own instability. He cycled between periods of elation and periods of extreme depression, in which he would have destroyed himself, had he the means.

During the periods of elation he made great plans for fighting against the X creatures-after he escaped. He was not sure how or when, but, momentarily, he was sure. He would lead the crusade himself; rockets could withstand the dead zone of the Pillars and the cloud; atomic bombs could destroy the dynamic balance of the Pillars. They would harry them and hunt them down; the globe would once again be the kingdom of man, to whom it belonged.

During the bitter periods of relapse he would realize clearly that the puny engineering of mankind would be of no force against the powers and knowledge of the creatures who built the Pillars, who kidnapped himself and Graves in such a casual and mysterious a fashion. They were outclassed.