In the meantime I had left Los Alamos, but I did not forget about it. I went back to a conference which closed off, supposed to close off, and said it closed off research on the hydrogen bomb. That kind of research, which was supposed to get thermonuclear reactions very fast before too much radiation could be emitted. The conference thought that this would work, but I kept to think of modifications. One of them looked particularly simple, in which there was equilibrium between the thermonuclear reaction and fission and in which some light elements, like lithium, was also involved. Some thermonuclear reactions originating from the light elements which did not give much energy, but which gave rapidly a great number of- of added neutrons. This kind of thing, either with the light elements or otherwise, we called a Booster and was generally accepted and tried out. Another one was, a big and clumsy subject- substance, where again with the help of light elements you could get a lot of yield. We called it the Alarm Clock, because we said that would wake up people to the fact that new things can be done. It was a great secret at that time. We never tried it out. It turned out that the Soviets thought of very similar things and their first attempts were in that direction.