A man who has been shaken by a two-ton blockbuster has a frame of reference. He can equate the impact of an H-bomb with his own experience, even though the H-bomb blast is a million times more powerful than the shock he endured. To someone who has never felt a bomb, bomb is only a word. An H-bomb's fireball is something you see on television. It is not something that incinerates you to a cinder in the thousandth part of a second. So the H-bomb is beyond the imagination of all but a few Americans, while the British, Germans, and Japanese can comprehend it, if vaguely. And only the Japanese have personal understanding of atomic heat and radiation.