INTRODUCTION This is a preliminary report, and therefore, does not give either complete or final results of the work of the various projects. No in- formation on the construction of the device is included, in order that the classification may be kept to Secret Restricted Data. ————— pELeTEO It was detonated as the Flathead Shot ona barge off Yurochi Tsland, Bikini Atoll at 0626,901 June 12, 1956. uaa wed _ Results of the various ex- periments are given in the following puges. mEu ror fF “LEG t emir.