he Period 2100, April 1h, 1955 to 1630, April 20, 1955 CL 562-P CL 563-P Open tub Coveredtub- 5305 + 3.3 dom total 1 3h +1,8 " 5S. Period 1800, April 28, 1955 to 0930, May 13, 1955 CL 617-P CL 618-P CL 619-P Open tub Covered tub Wet" tub 67 + 7 dpm total 83*9 " Mm 72.8 + 4.9 dpm total 6. Period 1100, May 13, 1955 to 1130, May 23, 1955 CL 627-P CL 628-P Open tub Covered tub 90 + 5 dpm total 70 + 5 tt " 7. Period 1700, May 23, 1955 to 1030, June 6, 1955 CL 64,8 CL 645. CL 646 Open tub Covered tub Met" tub 210 + 8 dpm total 239 ¥ 12" 4 221*68 " The agreement in total Sr90 activity collected by each of the several methods is gratifying. The only significant discrepancy is the low value for CL 563-P which might be explained by the occurrence of a very heavy rainfall with a possible resultant loss of sample due to splashing off the plastic cover, Another possibility is the occurrence of dry fallout which could have been blown off the plastic cover by surface winds. It appears that the Sr70 is water soluble at the time of collection and is not absorbed on the walls of the vessels, It is further indicated that once deposited in rains, the Sr70 fallout does not blow around significantly. These results testify to the adequacy of the water collection and chemical separation procedures used and indicate that an open tub provides for reliable collection of precipitation for extended periods of time. Since the Sr acti- vity is apparently quite soluble, large volume collections can be safely aliquotted to reduce the sample shipment problem. Thus, the collection of precipitation appears to be a practicable method to auguent, or even replace, the sticky paper collector as a general method of world wide monitoring.