infra-red measurements on shots Butternut and Koa as instrument checks and to obtain correlation data. A P2V also participated on events Butternut and Koa for instrumentation checks and to obtain data for correlation of data from a surface detonation with those from shots Teak and Orange. On Butternut the monochromator failed to function properly, but the mapper functloned satisfactorily. On Koa both instruments operated well. No data were received from the canister instruments on the drag line. Tentative conclusions which can be made at this time are: lL. The Yucca shot appeared timewise as a detonation of one-tenth its actual yield. 2. The time to normal second maximum scales directly as the relative density to the one-third power. 3. The apparent yield scales directly as the relative density to the two-thirds power. 4. The radius of the fireball at time to second maximum scales inversely as the relative density to the one-sixth power. 5. No definite indication was received of a change in partition of en- ergy since the apparent change was not sufficient to be conclusive. If there is a change, it would appear to scale inversely as the relative density to the 0.031 power. The experiments on effects of atomic weapons on materials and evaluation of a skin simulant were carried out on shots Yellowwood and Walnut. Approximately 30 skin simulant specimens in various configurations, including< bare and blackened unclothed samples, samples clothed with contact and spaced fabrics, and samples with various apertures were exposed. Timetemperature histories of the specimens were recorded. In addition, recording calorimeters and radiometers were used to measure the thermal radiation incident at the station. Ablation and neutron vulnerability studies were carried out on shot Cactus. For the experiments on ablation of material,two specimens designed to determine the rate and depth of melting of a spherical surface were exposed on a 100-ft tower so as to be within the fireball. These specimens contained instruments for measuring and recording the time history of the temperature of unprotected metal at various depths, specimen acceleration, late fireball] overpressure, and shockarrival time. Two additional specimens spaced 10 ft apart and rigidly connected were placed on the ground at a distance of 250 ft to measure the speed of sound inside the fireball. These specimens contained transducers and recorders for measuring the time of arrival of weak shocks from a series of small explosions set off at successive times after zero time. From these measurements it was hoped to cal- culate a time history of the gas temperature of the fireball. As yet, no results are available from these studies. In the case of the neutron bombardment experiment, the radiation level in the area precluded immediate recovery. When the level of activity diminished, a search of the area was made, but the instrument carrier could not be located. Program 9, General Support The mission of Program 9 was to provide documentary and technical photographic support to participating DOD agencies. The documentary support consisted of both still and motion picture coverage of project activities 35 Nea ht —_— 3Y