in dry soil; at a height of 100 ft the diameter would be 1800 ft, Dr. Sooville pointed out that the difference in these diameters is comparable with bombing errors, The (surface) damage distance is ’ taken as 1,5 crater radii, Next, "severe damage curves for structures" were presented. The blast scaling laws and parameters are well known, at least up to 15 MT from data on surface shots, Because the drag duration in- creases with energy the critical damage parameter.for heavy steel frame structures also varies, from 12 psi at 20 KT to 8 psi at 10 MT. Damage to brick structures is a straight crushing effect and does not show such trend. Thermal damage criteria are also, at least in part, a function of energy of burst. Since the heat dose is given over a longer period nee eeee Ste me saan STS cae se with thehigher yield weapons, more cal/cem® are required, a However, for producing second degree burns beneath clothing the criteria do not seem to depend on energy. The effects of prompt nuclear radiation are relatively insignificant for large yield weapons, since other effects predominate. Dr. Scoville next discussed the delayed radiation effects due fall-out to fall-out. He showed a map of isodose contours as inferred from the CASTLE tests. The highest contour shown was 50 r/hr at D $1 day. He indicated that the highest contamination of Bikini was about the same as that at Rongelap. Induced activity is not important; it all