On 31 January 1950, President Truman nade public the decision to develop a thermonuclear bomb, a decision which, of course, was to have great impact on Eniwetok Atoll. Tests of weapons with such large increases in yield and fallout radiation are not suitable for the ‘continental United States, but are better suited for the remoteness of the Pacific Proving Ground. To facilitate tests of devices that at first were limited to the 20-kiloton nominal yield of the Hiroshima weapon, the Nevada Proving Ground, near tas Vegas, Nevada, was additionally established in the autumn of 1950. The first tests there were in a 1951 series starting on 27 January. The Eniwetok Atoll test series also planned for 1951 was designated , as Operation Greenhouse and included, among other tests, activities related to thermonuclear research, but not yet involving a full thermonuclear explosion. Between 7 April and 24 May 1951, four tests from towers were conducted at Eniwetok, with the second one called Easy announced as 47 kiloton yield. 422 A full thermonuclear explosion was achieved the following year in the 1952 test series Operation Ivy at Eniwetok Atol] 4:8 This involved only two tests, but the first had considerable significance and consequence. The first was Test Mike, the first thermonuclear detonation and a ground level explosion amounting to 10.4 megatons (equivalent of 10.4 million tons of high explosive) on 31 October 1952 on a small island, Elugelab (Eluklapin in Marshallese, and Flora by the U.S. code name), at the north end of the Atoll]. Being a surface explosion and having this large yield, Test Mike actually removed this smal] “island from the Atoll] chain. A large reinforced concrete building built on the nearby large island of Engebi to test effects of pressure was partly damaged. ‘The second test of 7, 8. Reference T, p 125. Reference 1, p 135. ‘ 3 : 3) C