SUMMARY While the gummed film network fulfilled its original purpose of delineating fallout patterns, this report has been devoted to the extension of the B activity measurements to the estimation of sr? deposition and infinity gamma dose. Sr“~ 90 , d ~ 4 The computations have been based on a simple model, but yield estimates that are generally within a factor of two from measured values, It would be possible to improve the gummed film estimates by adopting a more sophisticated model, but the added cost would not be justified, The present results have required much greater effort than was expected and have appeared more slowly than was hoped, The gummed film Sr’~ 90 estimates are lower in most cases than the measured values at nearby sampling sites. The deviation is probably a com- bination of many effects: 1. 2. The estimate of sr70 yield may be low, particularly for fractionated debris, where long range fallout is enriched in this nuclide. The gummed film efficiency is variable and is probably lowest during heavy rainfalls when a large fraction of the Sr% is deposited, 3. The gummed film efficiency continues to decrease in the absence of qaree scale tests, for the percentage of long-lived Sr? and Os!’ increases and their retention is poor. , 4. The present model is poor during periods of repeated high yield tests, as there is no delay included for arrival time from either the troposphere or stratosphene. The debris is thus always considered to be fresher than the actual fallout. The results presented in this report have some value in the absence of direct measurements. While it is not possible to evaluate all situations, the data may be used for geographic interpolation between stations where sr?? results are available. It is also possible to make reasonable estimates for - 30 - ie