tower shots, According to Reference #10 there is a definite secondary maximra fall-out area 50 miles NNE of the J-S crater, and the maximm A Stokes’ Law fall-out from J-U is 10 miles NWF of the ground zero. analysis of the J-S secondary maximua indicates that according to the vertical wind distribution pattern, this secondary fall-out came from the upper pertion of the cloud. Since the fall-out from J-S and J-U shots covered ene to two thousand square miles, and because only sight to 10 square miles were examined during fall-out studies, it is the contention of this writer that such sampling was not representative. There is a great likelihoed that most of the fall-out downwind was not mea- sured. The Air Force Special Weapons Center also surveyed the J-S and J-T7fall-out area on D and Del days using aircraft. However, since all the readings (except ground zero and three miles downwind) are made from aircraft, it is not censidered reliable by itself. Air readings must be checked wth several ground readings before they could be can- sidered reliable. Also, it appears that as the yield of the bomb decreases, the apparent percentage fall-out increases, As a matter of fact for U/K, shot Ray (100 ft tower, 0.3 ET bomb) the percentage fallout appeared to ba in excess of 40%, This value was not entered in the tables since it is not considerec reliable. However, it does indicate that when the actual fall-out is small (because the bexzb yield is small) there is a tendency to overestimate the percentage fall-eut, If the bomb yield is large, a large area is contaminated and the intensity is high and readily measurable. Under such circuastances sanmplirg is bhatt adequate and the averaging process used in determining percentage fall-out DOC 258 C3-36417 ' : UNCLASSIFIED 19 one ~-