RESULTS Figures collected in 1-6 show graphically the decay rates of 1951 and 1952. Logarithm of radioactivity is related to log of time after detonation. legend of the figures. 104 samples Detonation date is stated in the The graphs do not show absolute levels of radioactivity, (although this may be computed by reference to Table 1) but rather permit a comparison of decay rates between samples. Table 1 lists, in the left-hand portion, samples whose decay curves appear reference data for in Figures 1-6, while the the five regions in the right-hand portion give measurements of slope as scaled from the graphs in such a manner as to consider most of the major inflections of the curves where observations were sufficiently ssiphadhepe frequent. Inflections of curvature might of course also be expected during the periods when observations were not made. The slopes of the straight portions of the curves were tabulated in the region that seemed chronologically most appropriate, except that if the entire curve was straight, the data were entered only in the first Thus, from the first region under "Negative slope----" nearly straight-line decays are seen to be numbers 81. Similarly, the last region contains, region. in Table 1 the 38, 41, 58, among others, and those en- tries for curves that were linear from the period of the first region through 2300 days after detonation.