1. AN EXPLOSIVE WHOSE DENSITY IS LESS THAN THAT OF WATER WHICH COMPRISES A FOAM WHEREIN SUBSTANTIALLY ALL THE CELLS ARE CLOSED AND IMPERVIOUS TO THE PASSING OF FLUID, SAID FOAM BEING A HOMOGENEOUS MIXTURE OF ABOUT 90 PERCENT TO ABOUT 70 PERCENT BY WEIGHT OF AN EXPLOSIVE FROM THE GROUP CONSISTING OF TRINITROTOLUENE, NITROCELLULOSE, PENTAERYTHRITOL, AND CYCLO TRIMETHYLENETRINITRAMINE AND A BINDER OF ABOUT 10 PERCENT TO ABOUT 30 PERCENT BY WEIGHT OF A THERMOSETTING POLYESTER RESIN.