have tended to minimize exposure to take a course that was probably feacty along the "hot line" of the BRAVO cloud. At 1900 Enewetak. a second cloud-track aircraft, Wilson 3, was sent east fubm The flight path was nearly straight east until beyond Ron and then the aircraft headed generally northeast while making severa zag swings across this northeast vector in search of the cloud. At t southern tip of one of these swings, after 2200, Wilson 3 got two rea that may have been the northern edge of the cloud, but these readings not much above the background readings taken throughout the flight. readings were taken at 10,000 feet (3.05 km) over the Rongelap and Ro atolls shortly after 2000 hours. It is clear that at this time Hq JTF 7 did not know where the clo was, nor where it had been. There was apparently no great concern ab this, however, as the Wilson 4 cloud-track flight was cancelled at 19 (Reference 26). The MIKE experience indicated that although less tha percent of the detonation's radioactive debris had been accounted for problems had occurred. The, controlling assumption was that the cloud gone out on the 65° bearing and that the tracking aircraft were simpl behind it. The morning's contamination of the fleet lying southeast Bikini and the unquantified report of contamination by the VP-29 P2v t aborted were not consistent, but this contamination was believed the r sult of a wind change at the 20,000-foot (6.1-km) level. This wind ch waS presumed to have resulted in a widespread east-west distribution o fine particles (Reference 16, p. K-5) and was apparently assumed to be minor irritation, not a major problen. During the briefing of the task force commander on the Estes at 20 a second message arrived from the Rongerik detachment. This message r iterated that the pen had been off the chart since 1450 and requested acknowledgment (Reference 83). At about the same time, messages were ceived from Wilson 3 indicating low readings above this area 16). (Referenc At 2200 a reply was prepared explaining to the Rongerik detachme 220 no