i and many had to be replaced during the operation. After Shot 1, several rafts capsized although they were designed to withstand the effect of 4 . 10-MT weapon, 5 miles distant. 3.2.3 Free-flosting Sea Stations The performance of free-floating buoys as collecting staticns was important to the main objectives of the present work. Although little data on fallout were secured from these stations, sufficient information was obtgined to determine the performance of the equipment and the suitability of the method. The following observations are pertinent: (a) satisfactory. Pesformance of the buoys and associated equipment was ; ‘the low-frequency transmitters together with the radio direction-finding gear aboard Naval units provided an adequate system for locating and identifying the buoys. The handling problem in place- ment and recovery raised some difficulties, perticwlarly in increasing seas, but was satisfactorily met. (b) The free-floating buoy syste was unsatisfactory for docu-~ menting fallout under the conditions of shot scheduling which prevailed after the first test. This statement would be true of any similar system having the prerequisite that the test take place within a 24-hr period specified 24 to 48 hr in advance. 3.2.4 Total Collectors From evidence giyen in Sections 4.2.1 and 5.1.2, modifications in the design of total collectors are indicated, Nevertheless, both devices used made satisfactory collections under some exposure conditions. As exrected from other experience, the principle of using simple continuously open (collecting) sampling devices was found satisfactory whenever only total radioactivity deposited per unit area was to be determined, Such devices are not satisfectory where it is desired to preserve the characteristics of the fallout because dilution by extrameous rain and dust occurs. 3.2,5 Belt Sampler The belt sampler was handicapped by too many moving parts which were exposed to the elements. It was badly corroded by sea spray; sand lodged in the gears or under the belt and caused the sampler to function poorly. The collecticn from this sampler on Shot 1 was much better than on subsequent shots. Considerable valuable data were obtained as shown in CLupter 4, 3.2.6 Liquid Droplet Sampler ~ The prototypes tested at CASTLE failed to operate in most instances. This failure was due both to a faulty triggering mechanism for indexing the trays and to the absence of liquid droplets in the fallout from most shots. Nonetheless this differential collector has 42