# ~ - ¥e 1%fe: ‘ ~ * me Vo: 4 Weight of sample was 0.35 gu. was approximately 68, The count per mimteper gran To check the washing method for the purpose of determining if the above count or part of it was due to particles adhering to the alga a second sample was placed in the same aquaria and covered with Bikini mad for ten minutes, sample was washed as above and counted. Sample weight was 0038 gM The count per minute per gram was approximately 19. that the washing wothod was inadequate. April 23rd. The This indicated The alga wasreplaced on A count will be made later with a special effort to lecate the source of activity. Another experiment was started April lst in aquariums §5 and #6, Some coral samples brought back from Bikint in 1947 were radioactive principelly because of an ofl scum adhering to the coral, Counts, uncorrected for geometry which was about 15%, of coral without the oil scum was about 3 per minute for a 2 gram sample. A sinilar sise sample coated on one surface with ofl seum had a count of 2800 per minute. Pieces of the ceral with the oil scum were chipped off and used to pave the bottom of aquarium #5. A thin coating of sand was added but no more than enough than the fish would seatter as it rested on the bottom. Thus the oil scum was in contact with the underside of the fish at all times except when the fish was moving, The reading on the Victoreen survey meter placed in aquarium #5 before water was added was as high aa 17 on the 1 scale which is roughly translated to 12 r per day. A S ml. sample of water on April 6th gave no count above background. The fish in this agqnarium has fed regularly from beginning of sxperiment te the present (May 3rd), Aquarium #6 was set up as a control and duplicated #5 except that qua