Genius: The Life and Science of Richard Feynman

by James Gleick

He considered seemingly remote contingencies: “During centrifuging some peculiar motion of the centrifuge might possibly gather metal together in one lump, possibly near the center.” The nightmare was that two batches, individually safe, might accidentally be combined. He asked what each possible stuck valve or missing supervisor might mean. In a few places he found that the procedures were too conservative. He noted minute details of the operations. “Is CT-1 empty when we drop from WK-1... ? Is P-2 empty when solt’n is transfered ... ? Supervisor OK’s solution of P-2’s ppt. Under what circumstances?” Eventually, meeting with senior army officers and company managers, he laid out a detailed program for ensuring safety. He also invented a practical method—using, once again, a variational method to solve an otherwise unsolvable integral equation—that would let engineers make a conservative approximation, on the spot, of the safe levels of bomb material stored in various geometrical layouts. A few people, long afterward, thought he had saved their lives.