Negotiations for some sort of ban on the testing of nuclear weapons continued in Geneva through 1962 and into 1963, with little to show. Then came great and unexpected news. On June 10, President Kennedy announced that the US would stop its atmospheric tests as a sign of support for the talks. A few weeks later, Khrushchev signaled back, saying that the USSR was in favor of a "partial test ban," one that would get around the difficulties of detecting underground blasts by exempting them. In other words, the nuclear nations would be able to continue to test their weapons, as long as they released no fallout into the atmosphere. After that, things started moving quickly. On August 5, after five years of negotiations, the US and USSR signed a treaty to ban all tests of nuclear weapons in the atmosphere, outer space, and under the sea. This "partial test ban" was the first significant weapons-limitation treaty of the Cold War, "a shaft of light," as Kennedy put it. He signed the treaty on October 7. Everyone was pleased with the development, including Pauling, who wrote Schweitzer that he was "very happy" about its ratification. It was not an end to war, but it was an important step in the right direction.