For many years, gummed film sampling comprised the only widespread network for measuring fallout, This technique fulfilled its original pur- poses of delineating the geographic distribution of fallout and indicating the time of arrival of radioactive material. While the test pattern re- mained simple and included only fission devices, it was also possible to estimate individual long-lived nuclides such as Sr” and to estimate the fallout infinity gamma dose, ; a More complex test patterns and delayed fallout from thermonuclear devices made the sr? and gamma dose estimates very difficult. Despite the complexities, considerable effort has been devoted to testing various mathematical models to allow computation of these two parameters and thus to extract the utmost from the available data, ‘This report describes the model adopted and gives the results of these computations in some detail, In ad- . dition, comparisons have been made with more direct measurements of gr90 fallout where these are available, The data indicate that useful information on Sr 90 deposition has been obtained by the gummed film technique. The gamma dose estimates cannot be rT ‘ 3 wee i - - confirmed, but are the best availatle for any network, Historical The first detection of radicactive fallout away from the site of the explosion was in Rochester, New York, in February of 1951, although web‘? had reported activity of unlmown origin in paperboard in 1945, r v &.. a fp i The Health and Safety Laboratory was subsequently given the responsibility of determining the relative fallout at distances beyond 200 miles from the Nevada test site. Later this responsibility was modified to delineating world-wide fallout from the megaton weapons fired in the Pacific and elsewhere, = - = 7 4 a