hal i EXPERIMENTAL DATA For the most part, the experimental data are derived from the average of duplicate daily gummed film samples analyzed as described in the section on Procedure. The monthly summaries of estimated Sr 90 deposition and ine [ | [ - finity gamma dose make up the bulk of this report, but certain data have been extracted in this section to compare with more direct measurements or with other estimates. The evaluations are separated into comparison of duplicate: stations , Sr? data and gamma dose datd@. There are certain cases where daily data are not available. Since these may enter into the evalua- 7 tions attempted, they are described below. During certain periods in 1955 and 1956, the daily gummed film samples were composited on a monthly basis for counting. The purpose of this com- ‘positing was not to reduce the counting load but was an attempt to collect sufficient gummed film ash to make a radiochemical analysis for sr”, . This effort was not successful as it was found that the collection efficiency for ‘sr was considerably poorer than the efficiency for the total mixed fission preducts, This was later confirmed by Welford 2) in his measurements on New York City samples. The composite samples have been treated in the computation process as ‘This should not lead ta any marked computation errors since the compositing wg though all activity had been deposited on the 15th of the sampling month. was only carried out during periods or at stations where local fallout was not expected. All composite samples are marked as such in the summary tables for each station. Because of the large number of samples heing handled and because of difficulties in the field, there are not always sufficient daily samples ~ 10 = |