Introduction. With the development of fission and subsequently of thermonuclear explosives, a very large source of cheap energy has become available. The problem of using this energy for peaceful purposes safely and economically presents itself as one of the most interesting and important of our time. In explosions the energy is released very suddenly. Conversion of this sudden release of energy at extremely high temperature and pressure into the form of useful work, either mechanical or chemical or thermal, must be accomplished in order for such explosions to have nonmilitary uses. The technical feasibility of such conversions in a number of different instances will be described in this article. At the same time one must be able to control nuisance effects. Examples of these are seismic effects, the blast and heat which at least in the atmosphere always accompany such explosions, and the problem of radioactivity. Even given the technical feasibility of these accomplishments, which in some cases seems quite clear from what is known already, one must prove economic feasibility. That is to say, one must show that the cost of certain nonmilitary undertakings will be considerably less by the use of nuclear explosions than by conventional methods.

The pion-pion interaction is of great theoretical importance and must be understood before the other and more familiar interactions can be systematically analyzed. Therefore, various experiments to verify the existence of a P resonance in the w w system are proposed.