"Damn near," he concurred. "Virgie, you may be of some help to me. Obviously you've been reading up on Maxwell."
"Obviously."
It was the simple truth. I had got a lot of use out of the prison library—even to the point of learning all there was to learn about Clerk Maxwell, one of the greatest of physicists, and his little demons. I had rehearsed it thoroughly for El Greco.
"Suppose," I said, "that you had a little compartment inside a pipe of flowing gas or liquid. That's what Maxwell said. Suppose the compartment had a little door that allowed molecules to enter or leave. You station a demon—that's what Maxie called them himself—at the door. The demon sees a hot molecule coming, he opens the door. He sees a cold one, he closes it. By and by, just like that, all the hot molecules are on one side of the door, all the cold ones—the slow ones, that is—on the other. Steam on one side, ice on the other, that's what it comes down to."
"That was what you saw with your own eyes," Theobald Greco reminded me.
"I admit it," I said. "And I admit I didn't understand. But I do now."
I understood plenty. Separate isotopes—separate elements, for that matter. Let your demon open the door to platinum, close it to lead. He could make you rich in no time.
He had, in fact, done just that for Greco.
