428 —_, yield. An alr burst of this sise at dam of a clear day (93 percent atmospheric transmission) is sufficient te produce chorioretinal burns a. monkeys ani rabbits =P.. man, At this yield and these jistances the energy of the first 50 ms of the - "bp detonation, and particularly that of the first pulse — da of little significance in the production of burns. The highes: incidence of turning securred in those animals whose eye exposu-e inclujed the periol from 6C through 290 ms. There is limited evilence that burns could be produced at s.mevhat greater liatinces under Llentisal con‘itinnsa of exposure at the Pacific = Proving Grounds, It is believei, however, that chorioretinal burning assumes its greatest significance for the pilot ant air crevs at high altitudes where specific abscrrtion effects by salt vater spray and excessive mmidity are not factors of atmospheric attenuation, Aijditional information is neete! on the spectrum of the atomic flash in order to predict the distan-es at which burning is significant, The rate of delivery of thermal energy 1s of prime importence in the production of chorioretinal burns, At near-threshold distir-es, filte-s -f the colors and densities tested will prewant chorioretinal turns; at intermeifiate distances these filters will reduce the inciience ani severity of the lesions. pest AVAN” eee copy COriTyD SANLA, RC lS