hal | The effect of fresh fallout from single bursts has been taken into account in some cases. headed "Formula", For these months, a figure also appears in the column This figure represents the actual value calculated by the | F model, while the figure under "Best Estimate" represents the value obtained after allowing for fresh fallout. In all other cases, the "Best Estimate" figure is also the calculated value, In the final totals, the pre-1954 data are based on single burst computations described in the "Historical" seétion of this report, NO Fog bo 7 4 - 38