"The trouble with uranium is that it doesn't make a big enough bang," said MacPherson. "People aren't impressed by it any more. The same goes for plutonium, even for lithium, at least for any size bomb we can make. The idea is to show the world something so convincing that they'll never even think of a war again. When they see every island in the Waaku chain wiped off the map, they'll get the point." * * * * * Avery creased another card and cleared his throat. "_Did_ you check the inverted twelve-by-twelve, Rothman?" "I suppose you think I forgot to. Have _you_ checked it?" "Yes, I have. I may not know much math, but I did check it." "Even after the Columbia boys said it was nonsense? Well, does it come out right?" "No, it doesn't! You multiply the inverted matrix by the original and you not only don't get zeros for all elements outside the diagonal, you get a haphazard assortment of ones and twos. Worse still, every element in the diagonal comes out equal to zero. The product of the two matrices is about as different from the identity matrix as anything could be. You're one of our most brilliant mathematicians--how could you manage to make so many mistakes in one set of calculations?" "Did I tell you that was an inverted matrix? Maybe, for this problem, you need something a little more advanced than algebra. Anyhow, if my math is all wrong, why did your first report okay it?" "What do you mean, my first report?" "The one you sent to Prexy. The one you later called in and burned. Except Prexy showed it to me and I photostated it. Here." Rothman reached into the pile of papers on his desk and drew out a little envelope. It contained photographic prints. He held one before Avery's glasses. "Does that look familiar?" Avery drew his hand across his forehead, but did not reply. "Is that true, Avery?" asked MacPherson. "Did you make a report okaying Rothman's calculations and then withdraw it?" "Well, what if I did? The report didn't seem to make me much more popular than Rothman was. What if some very influential people in Government explained to Prexy, and he explained to me, just how unpopular that first report might make me? Or suppose they didn't. Maybe I simply didn't find the mistakes in the math until later." Avery kept looking at his cards as he spoke. "Oh, great," said MacPherson. "Rothman gets put away here, Neill and I lose our jobs, and there's hell to pay in Washington, all because Avery says Rothman's math is full of holes. Now it turns out he wasn't sure and maybe was pressured into it. Grand. Between a screwball and a skunk, I'll choose the screwball. Maybe if Avery had stuck to his guns, there wouldn't have been any test." * * * * *