Ever since 1947 when it was founded by conscience-stricken scientists who had helped create the atomic bomb, The Bulletin of the Atomic Scientists has recorded the imminence of a nuclear holocaust with a "doomsday clock" on its cover. Two years ago, after the U.S. and U.S.S.R. signed their first nuclear arms limitation pact, the Bulletin's editors set back the clock to twelve minutes to midnightthe farthest it has ever been from that apocalyptic hour. Now the editors are no longer so optimistic. In the September issue, the clock's hands will be pushed forward to nine minutes before midnight. The editors cite a number of reasons for their new pessimism: the lack of a further arms agreement between the superpowers; the continued spread of nuclear weaponry, emphasized by India's entry into the "nuclear club"; the American promise of reactor technology to the "volatile" Middle East; and mankind's increasing vulnerability to nuclear sabotage and terrorism by amateur bomb makers.