Wa’f Dr. R. W. Carlson, an expert on special concrete mixes, who was made available to super. vise the special limonite mix, used in the gamma stations. These continuous contacts not only expedited construction but also facilitated introducing many changes in details which developed as individual scientific groups progressed with plans for the instrumentation which was to be installed in these special facilities. Preparation of layout plans and detailed designs for test construction was the responsibility of AEC engineers. Corollary tests were conducted for the Armed Services, plans and designs for which were prepared by the” respective participating Services. Plans for construction and rehabilitation of housing and utilities were the responsibilityy of the Joint Task Force, as was the construction of drone airplane facilities. Procurement responsibility for test construction materials was divided, by agreement, between the Task Force and the using services. In general, all common construction materials were procured by the Joint Task Force, using normal service channels and facilities of the Western Ocean Division of the Corps of Engineers, U. S. Army. By agreement with the AEC, the Corps of Engineers, the Medical Department, and the Chemical Corps, USA, the Bureau of Medicine and Surgery, the Bureau of Ships, the Bureau of Yards and Docks, and the Bureau of Aeronautics, USN, the AFSWP, and the Coast and Geodetic Survey participated. Details of their participation were worked out in consultation with the AEC and incorporated into test construction plans. Early planning for the laying of communications and electronics cable was charged to the Staff Communications Officer, Commander Christian L. Engleman. Operational responsibility for laying submarine cable necessary to instrumentation of the proving ground was vested in the Commander of the Naval Task Group, TG 7.3. This in~olved the laying of 914,050 feet of submarine cable. Some ground cable was laid as well, and assistance was given AEC technicians in tying in their instruments. The over-all plan of the proving ground required the preparation of three’ test-firing sites involving the erection of one 200-foot tower on each site plus prescribed instrumentation and housing for the instruments. Photographic towers had to be erected in positions which permitted the placement of cameras to photograph each of the tests. A control station where firing instruments were located and housing and certain recording instruments were located had to be constructed. The three test-firing sites determined upon were the islands of Engebi, Aomon-BiijiriRojoa, and Runit. Parry island was designated as the location for the control station. Photographic towers (75-foot) were located on the islands of Aomon, Runit, and Aniyaanii. These were located to permit the photographing of each shot in succession from the next succeeding tower in the order of the islands named above. Thus, f rorn the tower on Aomon the shot on Engebi was photographed, and so on. In addition, a photographic tower was located on a coral shoal in the north-centra] part of the lagoon, located so as to permit photographing all three tests. In the case of the Aomon test-firing site, the single island, Aomon, did not have the requisite operating area. The island of Biijiri was adjacent to Aomon, separated by a 700foot channel. In order to extend the operating area, a 30-foot-wide causeway had to be constructed to connect the two islands, Across this causeway the drone-controlled ground sample recovery tank was directed from Biijiri to the explosion area on Aomon just after the firing of test number two.