At lunch the adults talked, the boys listened. The scientist, his turban bandage looking stranger than ever, hit it off well with his elders. Any one would hit it off well with Mrs. Jenkins, who could have been friendly and gracious at a cannibal feast, but the boys were not used to seeing Mr. Jenkins in a chatty mood.

The boys were surprised to find out how much Mr. Jenkins knew about atomics. They had the usual low opinion of the mental processes of adults; Mr. Jenkins they respected but had subconsciously considered him the anachronism which most of his generation in fact was, a generation as a whole incapable of realizing that the world had changed completely a few years before, at Alamogordo, New Mexico, on July 16, 1945. Yet Mr. Jenkins seemed to know who Doctor Cargraves was and seemed to know that he had been retained until recently by North American Atomics. The boys listened carefully to find out what Doctor Cargraves planned to do next, but Mr. Jenkins did not ask and Cargraves did not volunteer the information.

After lunch the three and their guest went back to the clubhouse. Cargraves spent most of the afternoon spread over the bunk, telling stories of the early days at Oak Ridge when the prospect of drowning in the inescapable, adhesive mud was more dismaying than the ever-present danger of radioactive poisoning, and the story, old but ever new and eternally exciting, of the black, rainy morning in the New Mexico desert when a great purple-and-golden mushroom had climbed to the stratosphere, proclaiming that man had at last unloosed the power of the suns.

Then he shut up, claiming that he wanted to re-read the old H. Rider Haggard novel he had found. Ross and Morrie got busy at the bench; Art took a magazine. His eyes kept returning to his fabulous uncle. He noticed that the man did not seem to be turning the pages very often.

Quite a while later Doctor Cargraves put down his book. "What do you fellows know about atomics?"

The boys exchanged glances before Morrie ventured to answer. "Not much I guess. High-school physics can't touch it, really, and you can't mess with it in a home laboratory."

"That's right. But you are interested?"

"Oh, my, yes! We've read what we could—Pollard and Davidson, and Gamov's new book. But we don't have the math for atomics."

"How much math do you have?"

"Through differential equations."

"Huh?" Cargraves looked amazed. "Wait a minute. You guys are still in high school?"

"Just graduated."

"What kind of high school teaches differential equations? Or am I an old fuddy-duddy?"

Morrie seemed almost defensive in his explanation. "It's a new approach. You have to pass a test, then they give you algebra through quadratics, plane and spherical trigonometry, plane and solid geometry, and plane and solid analytical geometry all in one course, stirred in together. When you finish that course- and you take it as slow or as fast as you like -you go on."

Cargraves shook his head. "There've been some changes made while I was busy with the neutrons. Okay, Quiz Kids, at that rate you'll be ready for quantum theory and wave mechanics before long. But I wonder how they go about cramming you this way? Do you savvy the postulational notion in math?"

"Why, I think so."

"Tell me."

Morrie took a deep breath. "No mathematics has any reality of its own, not even common arithmetic. All mathematics is purely an invention of the mind, with no connection with the world around us, except that we find some mathematics convenient in describing things."

"Go on. You're doing fine!"

"Even then it isn't real- or isn't ‘true' -the way the ancients thought of it. Any system of mathematics is derived from purely arbitrary assumptions, called ‘postulates', the sort of thing the ancients called ‘axioms.'"

"Your jets are driving, kid! How about the operational notion in scientific theory? No... Art-you tell me."

Art looked embarrassed; Morrie looked pleased but relieved. "Well, uh... the operational idea is, uh, it's building up your theory in terms of the operations you perform, like measuring, or timing, so that you don't go reading into the experiments things that aren't there."

Cargraves nodded. "That's good enough—it shows you know what you're talking about." He kept quiet for a long time, then he added, "You fellows really interested in rockets?"

Ross answered this time, "Why, er, yes, we are. Rockets among other things. We would certainly like to have a go at those junior prizes."

"That's all?"

"Well, no, not exactly. I guess we all think, well, maybe some day..." His voice trailed off.

"I think I see." Cargraves sat up. "But why bother with the competition? After all, as you pointed out, model rockets can't touch the full-sized commercial jobs. The prizes are offered just to keep up interest in rocketry—it's like the model airplane meets they used to have when I was a kid. But you guys can do better than that—why don't you go in for the senior prizes?"

Three sets of eyes were fixed on him. "What do you mean?" Cargraves shrugged. "Why don't you go to the moon with me?"

THE SILENCE THAT FILLED THE clubhouse had a solid quality, as if one could slice it and make sandwiches. Ross recovered his voice first. "You don't mean it," he said in a hushed tone.

"But I do," Doctor Cargraves answered evenly. "I mean it quite seriously. I propose to try to make a trip to the moon. I'd like to have you fellows with me. Art," he added, "close your mouth. You'll make a draft."

Art gulped, did as he was told, then promptly opened it again. "But look," he said, his words racing, "Uncle Don, if you take us—I mean, how could we-or if we did, what would we use for—how do you propose-"

"Easy, easy!" Cargraves protested. "All of you keep quiet and I'll tell you what I have in mind. Then you can think it over and tell me whether or not you want to go for it."

Morrie slapped the bench beside him. "I don't care," he said, "I don't care if you're going to try to fly there on your own broom—I'm in. I'm going along."

"So am I," Ross added quickly, moistening his lips.

Art looked wildly at the other two. "But I didn't mean that I wasn't—I was just asking—Oh, shucks! Me, too! You know that."

The young scientist gave the impression of bowing without getting up.

"Gentlemen, I appreciate the confidence you place in me. But you are not committed to anything just yet."

"But-"

"So kindly pipe down," he went on, "and I'll lay out my cards, face up. Then we'll talk. Have you guys ever taken an oath?"

"Oh, sure—Scout Oath, anyhow."

"I was a witness in court once."

"Fine. I want you all to promise, on your honor, not to spill anything I tell you without my specific permission, whether we do business or not. It is understood that you are not bound thereby to remain silent if you are morally obligated to speak up—you are free to tell on me if there are moral or legal reasons why you should. Otherwise, you keep mum—on your honor. How about it?"

"Yes, sir!"

"Right!"

"Check."

"Okay," agreed Cargraves, settling back on his spine. "That was mostly a matter of form, to impress you with the necessity of keeping your lips buttoned. You'll understand why, later. Now here is the idea: All my life I've wanted to see the day when men would conquer space and explore the planets—and I wanted to take part in it. I don't have to tell you how that feels." He waved a hand at the book shelves. "Those books show me you understand it; you've got the madness yourselves. Besides that, what I saw out on your rocket grounds, what I see here, what I saw yesterday when I sneaked a look in Art's lab, shows me that you aren't satisfied just to dream about it and read about it—you want to do something. Right?"