} Figure 18, [tf 3 2. (upper). Autoradiograph actual size of Biijiri- Rkojoa dredged sand on 3/4-inch scotch tape. Figure 18, (middle). Photograph, 1.8x, of the same sand preparation partially illuminated from below through a positive transparency of its own autograph. Figure 18, (lower). Photomicrograph, 20x, of the large radio- active particle near top center of preceding figure. This irregular, chalky particle weighing 0.6 mg, when removed to a plate on May 18, 1953, counted 5,300/m in the Nucleometer. - 89 - eo VESTS