2 thus necessary to estimate the cumulative gammadose by indirect means. In calculating the dose, it has been as- sumed that the daily fallout is deposited uniformly on an infinite smooth plane, where it remainsto infinite time. The integrated infinite dose for each daily fallout is calculated from the measured beta Table 1. Fallout at stations outside continental United States, October 1952 to September 1955. Stations that have not sampled continuously since October 1952 are indicated by an asterisk. Station 1. Anchorage, Alaska 2. 3. +, 5. 6. 7. Edmonton, Alberta Regina, Saskatchewan Winnipeg, Manitoba Churchill, Manitoba Moosoonee, Ontario North Bay, Ontario 8. Ottawa. Ontario 9. Montreal, Quebec 10. Seven Islands, Quebec lt, Moncton, New Brunswick 12. Goose Bay, Labrador* 13. Stephenville, Newfoundland 14. Thule, Greenland 15. Keflavik, Iceland 16. San Juan, Puerto Rico* 17. Bermuda 18. Mexico City, Mexico Mixedfission products Strontium-90 /mni2) 62 2.7 (mc/mi?) 78 82 95 50 67 100 110 110 84 83 160 120 50 92 (me/mi 2.8 3.0 3.6 9 2.8 3.1 3.4 4.0 3.3 3.7 4.0 4.3 2.0 2.9 Gamma dose (mrad ) 6.5 7.6 9.3 14 4.1 12 12 12 13 12 10 13 18 3.6 8.1 100 96 110 3.9 4.6 5.1 14 19 22 89 50 51 4.1 2.6 2.6 15 10 10 24. La Paz, Bolivia 25. Belem, Brazil 92 74 4.2 3.4 27, Buenos Aires, Argentina 60 2.8 19. San Jose, Costa Rica 20. Panama Canal Zone 21. Bogota, Colombia 22, Quito, Ecuador 23. Lima, Peru 26. Sao Paulo, Brazil 28. Prestwick, Scotland 29. 30. 31. 32. 63 50 53 87 Oslo, Norway* Rhein Main, Germany Sidi Slimane, Morocco* Tripoli, Libya 56 100 64 83 34, Lagos, Nigeria* 35. Leopoldville, Belgian Congo* 36. Addis Ababa, Ethiopia* 33. Dakar, French West Africa 37. Pretoria, Union of South Africa 38. Durban, Union of South Africa* 39. Colombo, Ceylon* 40. Singapore, Malaya* 41. Misawa, Japan* 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. Tokyo, Japan* Hiroshima, Japan Nagasaki, Japan* Kadena, Okinawa* Taipei, Taiwan* Manila, Philippine Islands* Iwo Jima* Yap, Caroline Islands* Guam, Caroline Islands Truk, Caroline Islands* Ponape, Caroline Islands* Wake Island* Noumea, New Caledonia* 55, Sydney, Australia* 56. Melbourne, Australia* 57. Wellington, New Zealand* 58. Honolulu, Hawaii 59, Johnston Island* 60. Canton Island* 61. Dhahran, Saudi Arabia* 62. Beirut, Lebanon* 3.2 1.8 2.7 3.8 11 5.0 14 12 9.7 9.4 7.9 2.5 3.5 2.5 4.0 6.2 9.0 6.6 12 33 70 110 1.9 3.4 4.2 4.6 8.0 10 91 95 4.7 4.6 23 18 100 66 92 76 100 110 290 170 160 190 240 89 60 3.8 3.2 4.9 4.0 4.6 6.6 24 9.0 8.5 9.2 14 3.6 3.2 13 11 16 14 16 29 150 40 40 47 63 13 12 47 2.1 74 39 34 73 65 40 83 130 86 57 73 3.6 2.0 19 2.8 3.5 2.1 3.5 5.9 4.2 3.4 3.3 8.0 4.2 4.9 9.6 12 6.6 6.4 15 28 19 79 8.4 activity, using the known isotopic com- position of the sample and the known gammacharacteristics. The sum of these integrated infinite doses from each of the daily samples collected during any given time represents the estimated gamma dose for infinite time delivered to popu- lations who are exposed from the start of the sampling period. For practicalestimates, the infinite dose is delivered in 2 to 4 years after fallout. The integrated gammadoseis sensitive to the time of fallout, particularly in those parts of the world in which fallout may occur within | or 2 days of the detona- tion. In such cases, the bulk of the gamma dose is delivered within | month or so after fallout. It is thus desirable to know the time of fallout, at least to the nearest day, and for this reason daily samples are collected. The United States collections were begun on a systematic basis in the fall of 1951. However, because of the way in which the data were organized prior to the fall of 1952, it has not proved practical to calculate the gamma doseesti- matesprior to this date. An exception has been madein Salt Lake City, Utah, which is the only location beyond the immediate vicinity of the Nevada test site known to have received a gamma dose during this period that is significant in relation to the total received since October 1952. Findings The cumulative mixed fission product data as of | January 1956 are summarized on the world-wide mapin Fig. 1, and strontium-90 and gamma dose data: are given in Table |. The United States data arelisted individually in Table 2. Theestimates of mixed fission products and strontium-90 in the United States include the period from October 1951 to September 1955. Although some of the foreign stations began collections in Oc- tober 1952, not all of them have sampled continuously since that time; these are indicated by an asterisk. Full data are available from the Pacific and Asian locations for the 1952 and 1954 Pacific tests, but they are not always available during 1953, when a Nevadatest series was con- ducted. Some of the European, African, and South Americanstations did not collect samples during the Pacific test series in 1952. The missing data at these foreign stations have been estimated by regional interpolation. All stations have been sampling continuously since 1 January 1954, andit is since that time that the bulk of the fallout té date has occurred at most overseas stations. The gamma doses, which are derived by calculation from the fallout of mixed fission products, are not available prior