established, An automatic tide gauge could be installed at one location, and tide staff observatioms could be recorded over an extended period at the other locations as work progressed, at a very low cost in manhours. The interrelation could be established by taking the mean of a series of simultaneous observations at all locations. DESIGN SURVEY No local control was available on the Project islands fer use in completing early design surveys. Because these surveys conld not wait on establishment of permanent controls to specified accuracy, it was necessary to establish local control suitable for topographic and hydrographic surveys. Later surveys were made to provide accurate monumented control points. This preliminary horizontal control consisted of stadia or chained traverses of approximately third order, as required on the individual islands. Vertical control had been established by temporary datum. The design surveys included topographical mapping of the Project islands, including locating of structures which would influence design, and hydrography for piers, causeways, and channel locations. Topographic surveys were made on sixteen Project islands. Early surveys were made with limited personnel, and in order to expedite the furnishing of information for the Home Office to start design, the field work was held to a minimum, Existing structures that would influence de- sign were located, and sufficient spot elevations were furnished to con- trol grades, This information was plotted at the Jobsite and field sketches transmitted to the Home Office. When additional personnel had arrived, camplete topographic maps were prepared, including contours at varying scales to meet design requirements, Profiles and cross-sections were taken of existing and proposed airstrip locations, Detailed information was furnished on structures such as the Coral Head Photo Tower. Existing facilities at the north end of Eniwetok Island were located for purposes of planning the interim camp. Hydrography in connection with channel, pier, and causeway locations, and the establishment of secondary stations suitable as navigational aids and as comtrol for fixed positions during the laying of submarine cable assumed a magnitude not originally planned. Pier location or improvement surveys were made at eight locations. In addition to location of existing facilities, soundings were required of the general area, and in some cases of a channel to deep water, At Bogallua the inner reef was surveyed to provide hydrography from which a study could be made to determine methods of erosion control and a channel through the reef to the island. 5-67