condition or that can be economically repaired, will be discussed later. This type of structure is also contemplated for office and commnication buildings and mess halls on experiment islands. Other Building Construction. If dispersed power plants are used, it is recommended that those plants adjacent to the Timing Buildings and the personnel housing areas on the experiment islands be housed in permanent structures of reinforced concrete, partially below ground and protected on the side toward the zero tower by earth revetment so that these plants will be protected and may be maintained between experiments. For those plants adjacent to zero tow- ers and photo towers, if used, it is recommended that the aluminum structures be used. Under "Electrical Power Supply Systems" the relative merits of one or two central power plants and many small plants are discussed in detail. Due to the short period of occupancy for personnel on experiment islands, it is proposed to utilize tents on concrete slabs for housing. It is proposed to provide canvas tents having wood frames, with a double roof. The upper roof being supported about a foot above the main roof on wood frame. The sides of the tents can be raised and supported as projecting canopies for ventilation. It is planned that all tents will be identical although some may be occupied by two men and some by four men. The use of tents provide great flexibility to add or omit quarters as changes in requirements develop and are low in cost of installation. The concrete slabs will remain without maintenance during the roll-up period and the tents may be expended, Salvage. The aluminum structures and tents can be salvaged from the experi- ment islands, providing personnel for dismantling them will not interfere with experimental operations. In the cost estimate these items will be considered expended. Iv - 16