We met at 11:00 a.m. today. That is, Stalin, Churchill, and the U.S. president. But I had a most important session with Lord Mountbatten and General Marshall before that. We have discovered the most terrible bomb in the history of the world. It may be the fire destruction prophesied in the Euphrates Valley era, after Noah and his fabulous ark. Anyway we think we have found the way to cause a disintegration of the atom. An experiment in the New Mexican desert was startling - to put it mildly. Thirteen pounds of the explosive caused the complete disintegration of a steel tower sixty feet high, created a crater six feet deep and twelve hundred feet in diameter, knocked over a steel tower a half mile away, and knocked men down ten thousand yards away. The explosion was visible for more than two hundred miles and audible for forty miles and more.

This weapon is to be used against Japan between now and August 10. I have told the secretary of war, Mr. Stimson, to use it so that military objectives and soldiers and sailors are the target and not women and children. Even if the Japs are savages, ruthless, merciless and fanatic, we as the leader of the world for the common welfare cannot drop this terrible bomb on the old capital or the new. He and I are in accord. The target will be a purely military one and we will issue a warning statement asking the Japs to surrender and save lives. I'm sure they will not do that, but we will have given them the chance. It is certainly a good thing for the world that Hitler's crowd or Stalin's did not discover this atomic bomb. It seems to be the most terrible thing ever discovered, but it can be made the most useful.