are calculated from R-values averaged throughout the cloud for the first. four hours, The fractions for Oak are also from averages, here in the light and variable stratum, while for Walnut the stabilized condition shown in Figure 3.1 is used. Sample 980 L for Oak is not included due to the poor sampling conditions. The fractions of these nuclides remaining in the cloud after one day are given in Table 3.2. These numbers are to be interpreted as the quan- tity of material which does not come down in the local area, The limits assigned are derived from the variability in the data. f TABLE VERO EN” 3,2 - oo 2 FRACTIONS OF NUCLIDES LEFT IN CLOUD AFTER ONE DAY Mo?? Koa sr 79 . Cs137 44 20 64 Walnut 3045 41 78 Oak 15 £10 45 61 Of the curves for the fraction of Mo?? left in the clouds, the one for the water surface burst shows to a considerable degree the behaviour anticipated when the project was planned. On the reef shot, the points appear to be fluctuating around a fraction of 0.15, whereas for the land surface detonation there is insufficient data to do anything but extrapolate beyond SAN BRUNO FE KC 4s oe te : 6.5 hours, Since it is likely that the fission ratios would be around one a 7