- 20 - gamma readings, concentrations of total beta activity in air and gross beta activity on gummed paper. All of these paper studies suffer such severe uncertainties as to seriously question their usefulness. For example, local fallout patterns can have sharp gradients as illustrated in Figure 5. I have measured external gamma radiation levels in local fallout patterns that have varied one from the other by factors of 5 to 10, all within a few hundred meters. More than one paper study has been done using past monitoring data and attempting to establish correlations between external gamma readings and the amount of iodine-131 in milk. recall one meticulously prepared study. 17, I The mathematics was elegant. The only trouble was that the author had not determined, for example, that the external gamma readings le used were taken by monitors outside of a bar within the town while the pasture land was miles down the road. The monitors were not derelict in their duty since their first obligation was to assure safety of persons at the time of the fallout and they went to the places where people were located. There was a carefully documented testi8- performed after some leakage occurred following an underground nuclear detonation on March 13, 1964, at the Nevada Test Site. It showed that the amount of iodine-131 deposited on one farm about 70 miles from the test site differed from another by factors of two to five even though the farms were within five miles DOEAiRCHIVi other in a broad valley with no significant topographical features separating them. In fact, the amounts of deposited iodine-131 at two places only