a G. t 4 Weight of sample was 0.35 gm. The count per minute per gram was approximately 68, 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 md for ten minutes. sample was washed as above and counted. Sample weight was 0.38 gn. The count per minute per gram was approximately 19, that the washing method was inadequate. April 23rd. The This indicated The alga was replaced on A count will be made later with a special effort to locate the source of activity, Another experiment was started April lst in aquariums #5 and #6, Some coral samples brought back from Bikini in 1947 were radioactive principally because of an o11 scum adhering to the coral, Counts, uncorrected for geometry which was about 15%, of coral without the oil scum was about 3 per mimite for a 2 gram sample. A similar size sample coated on one surface with ofl scum had a count of 2800 per mimite. Piaces of the coral with the o11 scum were chipped off A thin coating of sand was and used to pave the bottom of aquarium #5, added but no more than enough than the figh would scatter as it rested on the bottom. Thus the oil scum was in contact with ths 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 as 17 on the 1 scale which is roughly translated to 12 r per day. A 5 ml, sample of water on April 6th gave no count above background. The fish in this aquarium has fad regularly from beginning of experiment to the present (May 3rd). Aquarium #6 was set up as a control and duplicated #5 except that qua DOS ARCHIVES a