.aectionsof selected areas~ and setting reference marks mnning cross-. with precise measurementsto buil~ng and other structure corners for later displacementtie-ins. Lccation overlays were furnished the AEC representatives,and special operationalcharts were rmde Up for the J-3 Section. The accuracy requirementOf first order triangulationfor the photo towers and second order traverse for the zero-timimg station lines have been satisfied. The base line used in the triangulationhas a probable error of 1 part in Z,1OO,OOO. The zero-timing lines varied froma probable errvr of 1 part in 350,000 to 1 part in 800,000. The tie-ins of other lines to these were of third order, or 1 prt in 5,000. in the lagoon so that it could be The building of station !’Reef)t occupied during triangulationmade it possible to achieve the first order work. The use of the LSTS during the initial stages of the survey protided excellent quarters, and gave the party the desired mobility. Officers and crews of these ships were most cooperative. The operation of the section progressed as planned. During the months of December and January, the section missed its staff representation when the section engineer was recalled to Washington, but this situationwas corrected in February by his return. Much of the work done by this section will be available and useful for future experiments. The technical parts of this report should be given careful custody, both here on Eniwetok and in the future. A 62 Section XVI