June BB, 1951 4A. G, Graves Table IV indicates the effect of particle size. generally raised The levels are at the distances of interest -- 20 microns is about the worst sige -- but it is apparent that the predictions ars Duginning to favor the higner cloud height. If the mean particle size is 12.5 microns, all levels fall and the dose from the 1/2-mile cloud height, though down to 3r, is a factor 10 greater than the dose from the lemile cloud. In the case of 12.5particles, the doses are considerably greater for all cloud heights if the wind velocity is reduced from 10 to 5 mph. GAELEN L. FELT J-Division Office GLFslh Distribution: Cpy 13 thru SB - Folt