by precipitating the fog by means of an electrostatic field onto a continuously moving, specially sensitized film. Film reels were later removed from the device, developed, and analyzed. The electrostatic precipitator vas powered by. a 1 KVa motor generator and was capable of sampling for a maximum of 6 hr. At island stations it was started by a signal from a light trigger and munuaily on the YAG's, The automatic water drop collector was a device for collecting raindrops in flour filled trays when they were retained as pellets of dough, After a pre-determined numoer of rain drops had been collected, the device automatically changed trays. The collector was started by a signal from a light trigger. The mechanism for changing trays was driven by compressed gas and was criggered by a rain drop contacting a sensitive element. The area of the censitive element was adjusted so that there was a high probubility that a tray would be changed only after a pre~determined number of drops had fallen into it. 3.1.6 Trigsers The crincipal trigger wus a light-activateda device consisting of ‘ prbeger head, a trigger box, and a battery and yover cable assembly Fis. Ber)e a prototype radiuticn trigger was also tested as a back-up trigger. Its censitivity was so high tht it could not be used on the ccntuminated islands efter Shot 1, It may prove to be satisfactory after some modifications. Simple precsure-.ctuated trigsers were designed and ccnstructed at the site to elleviute the shortage of triggers that. occurred when spares vere burned after whot 1, 3.1.7 Free-floatinz Buoys Free-floating buoys vere used as collection stations in the cea @reas around pikini atoll. Ficure 3.4 shows the following details of construction: flatform to mount the gummed peper collector; antenna whips; untennz coils; identification flags; total collector; buoy float convaining the radio trunsmitter cnd b:ttery mower; and keel mount. Not shown are the weight «et the bottom of keel mount und the film bedge on the mast 2 ft above deck, The identifierc on the floats were single-stage crystal-controlled radio transmitters, operating on the fcllowine eutnorized frequencies* 1309375, 1243.75, 1206.25, 1159.375, 1129.375, 1087.5, 1062.5, 1026,875, 987.5, and 241.875 ke. There units had a useful life of 4 to 6 days before the batteries hui to be re-charged. The buoys were identified end located by radio dir.ction-finding gear avoard Naval Task uroup chips and aircraft. 3.2 EVALUATICN CF STATIONS AND EQUIPMENT It is difficult to mike a fair evuluction of the station and equipment at CASTiY because numerous chunses in shot scheduling and the * Circuit No. J113, assigned by letter from Headquarters, TG 7.1, JIF-7, J-22227, 15 Dec. 1953. 39