collected on selected trays from the SIC were also dissolved in the YAG 40 laboratory and aliquots of the resulting solution used for similar purposes. Information obtained in these ways, when combined with radiochemical results, provided a basis for establishing an average radionuclide composition from which air-ionization rates could be calculated. Measurement of the actual air-ionization rate above a simulated infinite plane was made on Site How. In addition to the record obtained by the TIR, periodic ionization-rate readings were made with a hand survey meter held 3 feet above the ground at each of the buried-tray (AOC,-B) locations. The number of fissions collected in these trays served both to calibrate the collections made by the major array on the tower and to establish experimental values of the ratio of roentgens per hour to fissions per square foot. Fission concentrations in a number of surfacewater samples collected from the YAG 39 and YAG 40 were also determined for use in conjunction with the average depth of penetration, to arrive at an independent estimate of the total amount of fallout deposited at these locations. It was intended to calibrate one of the oceanographic probes (SIO-D) directly by recording its response to the total fallout deposited in the tank aboard the YAG 39, and subsequently measuring the activities of water samples from the tank. Because it malfunctioned, the probe could not be calibrated in this way, but the samples were taken and fission concentrations estimated for each shot. Records were also obtained from the surface-monitoring devices (NYO-M) on the YAG 39 and YAG 40. These records could not be reduced to ocean-survey readings, however, because the instruments tended to accumulate surface contamination and lacked directional shielding. 27