of relative Presnnss: than ins voantk Sr? It is apparent, then, that July rainout is of mors recect origin than any of the preceeding months. It has been hypothesized that fallout material which is entering the troposphere from the stratesphere has « selective entrance zone near allout material is old and originated If the rH the mid-latitude region. from a high yield devicz, it is probable that the debris is stratospheric and upon entrance ints she troposphere can be brought down in rainfall. It follows that there would be more activity in rain ccecurring near the mid-latitudes. Scatter diagrams of gr79 activity versus inches of rainfall for a 1l values, regardless of location, > = = + all months are plotted? ir fizvr: 2 are plotted but stations belty Lo N (an arbitrary limit) appear as black dots on the plots, It is visually apparent from the scatter of the points that there is little ccrrelation on an overall basis, Considering a CQ separation of the data at lo” MN. there is better correlation found among activity (mc/mi©/in) of rain water for my et ee these stations is generality ctr The specific i 5 =~ southern stations. then Por northern sites for the duration of the sampling, and ths specific activity at each site does not vary considerably from month ti month. ible to obtain better correlation by using areas. un the ho° N separaticen, tr: uf fae Since it has bean For this purpose, ide Beas; a is expanded by considering even smaller four areas in different parts of the sampling network were chosen on the tasis of uniformity of specific activity throughout the samplirs zizis’ Ts:s areas represent the northeast, north- west, southeast, and ths conc. t_4 seztions of tre continental United States. The data for gach of tie. or 2 x _ mA “St s ~ Say “Na a SS a ne 22 2 letted in figure 3. oe “S i a a “AA ae —" mh o SAA — «a *e we hh. = a s ~JASS vee St oN .s 2 a 4 . .