., .-a .. . . .. <ON”FIDENTIA; A... A L...- .... . intensity with altitude had been studied and that he believed good delineation of fallout had been made. He added that a cloud model had been established which would allow more precision in predicting areas of local fallout, although it would not be possible to predict hot spots too well because of variation in wind. Also, existing methods were suitable for ~redicting variations in the size of contour areas between thermonuclear weapons with a high percentage of fission yield and those with a low percentage of fission yield. Mr. Libby requested that he be provided a copy of the report on the radiation effects program. He also inquired whether the project had studied strontium-90 fallout as well as fallout yielding gamma radiation and Colonel Maxwell replied that no data had been received on strontium-90 fa~out. Mr. Libby also asked Colonel Maxwell to inform him of any studies which had been made of the tons of material taken up by a shallow water shot as opposed to a deep water shot. Mlr. Libby said that when data on the program were more complete, he believed it wouid be desirable to arrange another briefing. Dr. Dunham commented briefly on the world-wide radiation fallout monitoring program which had been undertaken in conjunction with Operation REDWING and 6aid that complete data would not be received for a few weeks. However, with regard to intermediate tropospheric fallout, he said that no reading above 10 times the background radiation level had q.