7.3.2 Petrographic Analysis. All shots resulted in the formation of micro spheres: these particles represented the non-crystalline constituents and presumably included compounds from the device, fission products, device casing, and device support. All shots except Shot 6 resulted in collection of one or more of the following crystalline compounds: oxide, hydroxide, and carbonate of calcium, megnesium oxide, and sodium chloride. Shots 1 and 3 showed only calcium compounds, indicating that little if any sea water was vaporized. Shots 2 and 4 showed principally sodium chloride and magnesium oxide from sea water, although Shot 4 showed some calcium compounds, indicating that a small percentage of island material was vaporized in this shot. It is interesting to note that sodium and calcium compounds were absent as major constituents of the debris from Shots 5 and 6. It is significant, perhaps, that rain was recorded subsequent to both tests, which may have resulted in the leaching of these compounds. 7.3.3 Specific Beta Activity. From a plot of the number of particles per unit logarithmic interval of disintegrations per minute divided by the cube of the particle diameter in microns, a modal value for specific beta activity can be obtained from the apparent norma! distribution curve. The modal values for the Castle shots were only rough estimates, since the observed frequency distributions covered a broad spectrum of specific activity with no pronounced peaks. Modal values for the barge shots were much greater than those from island shots. 7.3.4 Operation of the Squeegee Sampler. Castle included the first full-scale operational test of the small size, high-pressure squeegee, although sufficient experimentation had been accomplished during Upshot-Knothole to indicate its suitability. For ease of sample removal from contaminated aircraft and handling enroute to processing laboratories, this method proved ideal. During Castle, the main malfunctions of the system consisted of hith-pressure leaks from fittings and connections, compressor difficulties, or faulty check-valve operation due to freeze~up at high altitudes, all of which caused either loss of sample or no collection. These defects were corrected, as Castle progressed, with improved operational procedures and maintenance. Of all squeegee flights during Castle, 68 percent resulted in successful missions and 18 percent were only partially successful in sample collection; 14 percent of the missions failed. The size of most good samples collected was adequate for assay. PP 99 Delered. 100