grammetry project determined nuclear-cloud parameters as a function of time andat- tempted to establish scaling relationships for yield. Program 18, the thermal-radiation program, was administered by LASL. As a resuit, the DOD had no projects devoted exclusively to thermal-radiation measurements. Instead. to obtain thermal data of interest and avoid duplication of the Los Alamos efforts, the DOD provided funds for enlarging slightly the scope of Program 18. In general, the principal objectives of the military-effect programs were reaiized. The numerous changes in shot schedules together with the repeated delcys due to un-~ favorable weather forced many reviaions and last-minute improvisations in many projects’ plans. For some—notably those concerned with documenting fallout —— much information was thereby lost; for other projects, such as those involving effects on aircraft, the repeated delays allowed completion of necessary maintenance between shots and resulted in almost 100-percent participation. Despite uncertain yields and delays, the blast program obtained a considerabie amount of worthwhile data and achieved its objectives. Wave forms from the surface gages were nonideal in shape for both overpressure and dynamic pressure and demonstrated that water is not an ideal surface—it sometimes had been presumed to be ideal. Precursors as such were not detected. The uncertainty of the free-air data did not permit any definite conclusions regarding the effects of 2 nonhomogeneous atmosphere on the blast wave. Data from a megaton burst over a shallow water layer indicated that except for the closein region, underwater pressures are of comparable magnitude to the direct air-blast overpressures at the same range. In contrast to results from Operation Ivy, studies at Castle indicated that surface water waves do emanate from the central region of the detonation and that refraction and reflection against reefs and shores can significantly affect their destructive capability. In the nuclear-radiation and fallout program, the unexpectedly high yield of Shot 1 caused destruction of much of the spare equipment on Site Tare, curtailing instrumenta~ tion on future shots; however, the important military significance of fallout over large _ areas beyond the blast- and thermal-damage envelopes was demonstrated dramatically. The realization that activity dissolved in sea water could be a measure of the fallout intensity provided the impetus for the water and aerial surveys that provided valuable data after Shots 5 and 6. In the blast-effect program, the instrumented, rigid concrete cubicle was exposed to a blast intensity from Shot 3 of only about a tenth of that predicted. Although the specific objective of that particular project was not accomplished, an evaluation of the blastloading data therefrom made by Sandia Corporation showed that two loading-prediction procedures were reasonably good. The documentation of air-blast effects on miscellaneous structures was an unplanned project of opportunity — one initiated because of the damaging, unexpectedly high yield of Shot 1. Crater size data was obtained as planned, increasing considerably the reliability in predictions of craters produced by megaton weapons. Despite unexpected deviations from predicted yields for Shots 1 and 3, breakage data and other results on damage to natural tree stands were obtained. The underwater minefield—-121 mines of various types set 180 feet deep and exposed to a 7.0-Mt surface detonation— gave data on the extent of neutralization of these mines by the detonation. Extensive data was obtained in the biomedical study of the individuals accidently ex- posed to significant amounts of fallout radiation. Total gamma dosages up to 182 r were received and produced the physical effects expected. The actual yield of Shot 1 was approximately 25 percent greater than the positioning