and it was necessary to obtain additional instruments to meet these needs. For instance, as late as December 1950, it was necessary to requisition and obtain as soon as possidie $8 desk and 11 wall telephone instruments to meet newly established requirements. The comparison of original es- timates and actual instrument installations is sham in Table 5.171. Individual installations of communications systems for the several sites were designed to meet the differing physical conditions and specjal use requirements of each site. It was originally understood that the underground telephone cable installed on Eniwetok Island for Operation Sandstone would be required for other facilities and could not be used for telephone loops. Preliminary estimates of material requirements were made and materials requisitioned. On March 9, 1950, advice was received that the installed cable on Eniwetok Island was in good condition and would not be required for any other purpose. It was also decided at this time that the Signal Corps would install the local telephone system for this Island. H & N plans and specifications were accordingly revised to use the existing underground cable for a major portion of the system of subscribers! loops. Original plans for Parry called for joint use of power poles for overhead telephone cable. Because of the increase in facilities required, it became necessary early in 1951 to provide additional underground telephone cable for intercommunicating sets and additional control and signal cable facilities. Since telephone facilities requirements had also materially increased, plans were made to install additional cable while the ditches were open. Overhead telephone cable was No. 22 AWG with double dry paper tape insulation and lead antimony sheath. It was spun to messenger with 0,091 inch OD lashing wire. Subseribers' loops on experiment island sites were designed to be installed at an underground depth of approximately two feet. The relative advantages of duplex pairs and paper-insulated lead covered cables were considered, and No. 17 AWG duplex similar and equal to Whitnew Blake No. 17 TBPR was selected on the basis of greater economy and flexibility. It required no skilled cable splicers for an installation intended for short-time use. Wherever possible these cables were installed in the same ditches as experiment control and signal cable. Locations of underground telephone cables and pairs were marked by posts. Because of the vital importance of the communications system to the Project and because of the highly specialized camminication work involved, the advice and assistance of people with similar experience was obtained for planning and executing this operation so as to insure its success and so as to avoid the difficulties experienced with submarine control cable for Operation Sandstone. The principal difficulty reported had been in keeping cable laying ships on the desired course under prevailing winds and at the same time laying cables without paying out cable at an excessive speed. 5-239