their radioactive debris from the population of the earth as effeciently as do underground shots. This fact, of course, makes the possibility of high altitude testing rounds even more attractive from a political viewpoint.” September, 1958: For the first time since the beginning of the year, a new device has entered PhaseIII and Sandia development work. This is the XW-50, the Nike Zeus warhead. The report on Hard Tack PhaseII indicates that present plans are for nine one point tests underground (three in tunnels), three balloon shots, two tower shots, and six tunnel shots. October, 1958: Another specific warhead is added to the Sandia development activity, the XW-51, onwhich informal notification of Phase III has been received. This is to have applications in the Davy Crockett and Falcon missile systems. | The summary of Hard Tack Phase II indicates a total of 37 tests divided as follows: Tunnel, 7; wells (vertical holds), six; balloons, eleven; towers, eleven; surface, two. November, 1958: For the first time under Plowshare, Sandia activity on studying feasibility and methods of digging a ship canal with nuclear explosions is discussed. December, 1958: Under specific devices, the XW-52 (Sergeant application) and the TX-53 are both added to the list of Phase III programs, noted as being preliminary in this phase.