APPEMDIX IV FALLOUT AMD SAIN SAUPLING PRhOGRAD Precipitation wes collected at six stations in and about the Eniwetok [roving Ground, Sampling stations were maintained on Parry Island, Eniwetok Island, Rongelap Island, Ujelang Island, Otirik Island and Wotho Island. The samples were collected in weekly compgsites, the precipitation falling in a collector funnel of O.4H® in area and detained in a carboy of approximately 19 liters volume, The depth of precipitation is obtained by dividing the total volume of water collected by the area of the collector. ffter washing the collector with approximately one liter of water to wash dry fellout ints the collecting bottle and thorouchly mixing the contents in the bottle by vigorous shaking, a one liter sample of the original collecticn was sent to the laboratory et Parry Island. Five ‘iundred milliliters of this one liter sample were evaporated to cryness on aluminum planchets. These nlanchets were counted for cross beta ectivity in the central laboratory of the Public Health Service Radiation Surveillance Network in Washington, 0.C, The counting was performed in a NC 7% Proportional Chamber using P-10 as the counting gas. This equipment cperates with en efficiency of about 35% for 3trontium-Yttrium90 beta particles. The samples were counted twice approximately 7 days apart. ‘/ssuming the Way-Yigner felation for the decay of fission products of ue Sby Slow neutrons (A,T 1,2 AoE5 1-2) the activity of the sample wes extrapolated to the time of end of collection, The results of these water samples have been tabulated and are attached, As an additional project many of these samples were counted daily and the decay curves run to check the tyne of decay. They were found to agree quite closely with the Way-ilegner "1.2 law." A plat of one of these samples is attached es an illustra- tion of this. 2\