hadn't said a word to anybody. I hadn't even said a word to myself. The fact of the matter was, I had completely forgotten what he was talking about. Kept his secret? I didn't even remember his secret. And it was driving me nuts!

"I was sure of you," he said, suddenly thawing. "I knew I could trust you. I must have—otherwise I certainly wouldn't have told you, would I?"

I smiled modestly. But inside I was fiercely cudgeling my brain.

He said suddenly, "All right, Virgie. You're entitled to something for having kept faith. I tell you what I'll do—I'll let you in on what I'm doing here."

All at once, the little muscles at the back of my neck began to tense up.

He would do what? "Let me in" on something? It was an unpleasantly familiar phrase. I had used it myself all too often.

"To begin with," said the Greek, focusing attentively on me, "you wonder, perhaps, what I was doing when you came in."

"I do," I said.

He hesitated. "Certain—particles, which are of importance to my research, have a tendency to go free. I can keep them under a measure of control only by means of electrostatic forces, generated in this." He waved the thing that looked like a toaster on a stick. "And as for what they do—well, watch."

l Greco began to putter with gleamy, glassy gadgets on one of the tables and I watched him with, I admit, a certain amount of suspicion.

"What are you doing, Greek?" I asked pretty bluntly.

He looked up. Surprisingly, I saw that the suspicion was mutual; he frowned and hesitated. Then he shook his head.

"No," he said. "For a minute I—but I can trust you, can't I? The man who kept my secret for ten long years."

"Of course," I said.

"All right." He poured water out of a beaker into a U-shaped tube, open at both ends. "Watch," he said. "Remember any of your college physics?"

"The way things go, I haven't had much time to keep up with—"

"All the better, all the better," he said. "Then you won't be able to steal anything."

I caught my breath. "Now listen—"

"No offense, Virgie," he said earnestly. "But this is a billion dollars and—No matter. When it comes right down to cases, you could know as much as all those fool professors of ours put together and it still wouldn't help you steal a thing."

He bobbed his head, smiled absently and went back to his gleamy gadgets. I tell you, I steamed. That settled it, as far as I was concerned. There was simply no excuse for such unjustified insults to my character. I certainly had no intention of attempting to take any unfair advantage, but if he was going to act that way....

He was asking for it. Actually and literally asking for it.

He rapped sharply on the U-tube with a glass stirring rod, seeking my attention.

"I'm watching," I told him, very amiable now that he'd made up my mind for me.

"Good. Now," he said, "you know what I do here in the plant?"

"Why—you make fertilizer. It says so on the sign."

"Ha! No," he said. "That is a blind. What I do is, I separate optical isomers."

"That's very nice," I said warmly. "I'm glad to hear it, Greek."

"Shut up," he retorted unexpectedly. "You don't have the foggiest notion of what an optical isomer is and you know it. But try and think. This isn't physics; it's organic chemistry. There are compounds that exist in two forms—apparently identical in all respects, except that one is the mirror image of the other. Like right-hand and left-hand gloves; one is the other, turned backwards. You understand so far?"

"Of course," I said.

e looked at me thoughtfully,