Eisenberg was apprehensive, but not, panic-stricken. His situation was decidedly interesting; he was no longer bored.

If he were a prisoner, it seemed likely that his captor would come to investigate him presently, perhaps to question him, perhaps to attempt to use him in some fashion. The fact that, he had been saved and not killed implied some sort of plans for his future. Very well, he would concentrate on meeting whatever exigency might come with a calm and resourceful mind. In the meantime, there was nothing he could do toward freeing himself; he had satisfied himself of that. This was a prison which would baffle Houdini-smooth continuous walls, no way to get a purchase.

He had thought once that he had a clue to escape; the cells had sanitary arrangements of some sort, for that which his body rejected went elsewhere. But he got no further with that lead; the cage was self-cleaning-and that was that. He could not tell how it was done. It baffled him.

Presently he slept again.

When he awoke, one element only was changed-the food and water had been replenished. The "day" passed without incident, save for his own busy fruitless thoughts.

And the next "day." And the next.

He determined to stay awake long enough to find out how food and water were placed in his cell. He made a colossal effort to do so, using drastic measures to stimulate his body into consciousness. He bit his lips, he bit his tongue. He nipped the lobes of his ears viciously with his nails. He concentrated on difficult mental feats.

Presently he dozed off; when he awoke, the food and water had been replenished.

The waking periods were followed by sleep, renewed hunger and thirst, the- satisfying of same, and more sleep. It was after the sixth or seventh sleep that he decided that some sort of a calendar was necessary to his mental health. He had no means of measuring time except by his sleeps; he arbitrarily designated them as days. He had no means of keeping records, save his own body. He made that do. A thumbnail shred, torn off, made a rough tattooing needle. Continued scratching of the same area on his thigh produced a red welt which persisted for a day or two, and could be renewed.

Seven welts made a week. The progression of such welts along ten fingers and ten toes gave him the means to measure twenty weeks-which was a much longer period than he anticipated any need to measure.

He had tallied the second set of seven thigh welts on the ring finger of his left hand when the next event occurred to disturb his solitude. When he awoke from the sleep following said tally, he became suddenly and overwhelmingly aware that he was not alone!

There was a human figure sleeping beside him. When he had convinced himself that he was truly wide awake-his dreams were thoroughly populated-he grasped the figure by the shoulder and shook it. "Doc!" he yelled. "Doc! Wake up!"

Graves opened his eyes, focused them, sat up, and put out his hand. "Hi, Bill," he remarked. "I'm damned glad to see you."

"Doc!" He pounded the older man on the back. "Doc! For Criminy sake! You don't know how glad I am to see you."

"I can guess."

"Look, Doc-where have you been? How did you get here?

Did the fireballs snag you, too?"

"One thing at a time, son. Let's have breakfast." There was a double ration of food and water on the "floor" near them. Graves picked up a sphere, nicked it expertly, and drank it without losing a drop. Eisenberg watched him knowingly.

"You've been here for some time."

"That's right."

"Did the fireballs get you the same time they got me?"

"No." He reached for the food. "I came up the Kanaka Pillar."

"What!"

"That's right. Matter of fact, I was looking for you."

"The hell you say!"

"But I do say. It looks as if my wild hypothesis was right; the Pillars and the fireballs are different manifestations of the same cause-X!"

It seemed almost possible to hear the wheels whir in Eisenberg's head. "But, Doc.... look here, Doc, that means your whole hypothesis was correct. Somebody did the whole thing. Somebody has us locked up here now."

"That's right." He munched slowly. He seemed tired, older and thinner than the way Eisenberg remembered him. "Evidence of intelligent control Always was. No other explanation."

"But who?"

"Ah!"

"Some foreign power? Are we up against something utterly new in the way of an attack?" -

"Hummph! Do you think the Russians, for instance, would bother to serve us water like this?" He held up one of the dainty little spheres.

"Who, then?"

"I wouldn't know. Call 'em Martians-that's a convenient way to think of them."

"Why Martians?"

"No reason. I said that was a convenient way to think of them."

"Convenient how?"

"Convenient because it keeps you from thinking of them as human beings-which they obviously aren't. Nor animals. Something very intelligent, but not animals, because they are smarter than we are. Martians."

"But... but- Wait a minute. Why do you assume that your X people aren't human? Why not humans who have a lot of stuff on the ball that we don't have? New scientific advances?"

"That's a fair question," Graves answered, picking his teeth with a forefinger. "I'll give you a fair answer. Because in the-present state of the world we know pretty near where alt the best minds are and what they are doing. Advances, like these couldn't be hidden and would be a long time in developing. X indicates evidence of a half a dozen different lines of development that are clear beyond our ken and which would require years of work by hundreds of researchers, to say the very least. Ipso facto, nonhuman science.

"Of course," he continued, "if you want to postulate a mad scientist and a secret laboratory, I can't argue with you. But I'm not writing Sunday supplements."

Bill Eisenberg kept very quiet for some time, while he considered what Graves said in the light of his own experience.

"You're right, Doc," he finally admitted. "Shucks-you're usually right when we have an argument. It has to be Martians. Oh, I don't mean inhabitants of Mars; I mean some form of intelligent life from outside this planet."

"Maybe."

"But you just said so!"

"No, I said it was a convenient way to look at it."

"But it has to be by elimination."

"Elimination is a tricky line of reasoning."

"What else could it be?"

"Mm-m-m. I'm not prepared to say just what I do think- yet. But there are stronger reasons than we have mentioned for concluding that we are up against nonhumans. Psychological reasons."

"What sort?"

"X doesn't treat prisoners in any fashion that arises out of human behavior patterns. Think it over."

They had a lot to talk about; much more than X, even though X was a subject they were bound to return to. Graves gave Bill a simple bald account of how he happened to go up the Pillar-an account which Bill found very moving for what was left out, rather than told. He felt suddenly very humble and unworthy as he looked at his elderly, frail friend.

"Doc, you don't look well."

"I'll do."

"That trip up the Pillar was hard on you. You shouldn't have tried it."

Graves shrugged. "I made out all right." But he had not, and Bill could see that he had not. The old man was "poorly."

They slept and they ate and they talked and they slept again. The routine that Eisenberg had grown used to alone continued, save with company. But Graves grew no stronger.

"Doc, it's up to us to do something about it."

"About what?"

"The whole situation. This thing that has happened to us is an intolerable menace to the whole human race. We don't know what may have happened down below-"