First Man by Clyde Brown

"It's about time," Orville said, "that we started figuring out a plan." He scraped the bottom of the can. The tuna tasted fine. He took a swig of pineapple juice and passed the can back to Harold.

"Yeah, I been thinking about that," said Harold.

"I've had more experience in that line than you, so maybe -- "

"Do you think mankind is ready for my secret?"

"There, you see?" Orville laughed heartily. "Now don't you worry about such things."

"But look what they did with the atomic bomb. And if this ever got loose -- "

"Harold!" Orville's laugh was less hearty. "Do you think you could keep this a secret? The minute we land, they'll be all over us. The government can impound this ship, you know."

"Won't do them any good. They can tear it all apart and never find out a thing."

Hours later, they were still arguing.

"If the government had it, they'd build a war machine and then the Russians would steal it -- "

"Harold! That's Communist talk!"

"Shoot! I'm no Communist!"

"You're playing right into their hands."

It went on and on. Then: "Harold -- as your neighbor -- won't you tell "me" what it is?"

"I'll try."

Orville sat up, tingling. You take gravity, Harold said. What do we know about it? Was it like a lot of rubber bands, stretching back and forth between everything, or was it a flow, like water? Now if it was a flow, it would have to flow back some way, or else you'd run out, wouldn't you? Then if you hooked onto this counter-flow --

Orville nodded. This wasn't so hard to understand. He felt a little nervous. "Go on, Harold."

"I guess it's none of those things." Harold gave his inane giggle.

Orville felt cheated. "You call this neighborly? Remember when I drove clear out into the country with a gallon of gas that time when you got stuck?"

"I'm trying. You gotta think of it up to that point, then you gotta think the "other" way. But you can't explain it. You just do it."