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WOKZEL AND HAKKISON 



[chap. 9 



to 12 submarine stations and the root-mean-square difference between the sur- 

 face and submarine measurements was 4.4 mgal (Harrison, 1959). This is 

 satisfactory considering the navigational uncertainties. The first full-scale 

 survey made with the meter was that in the Gulf of California from February 

 to April, 1959, during the Scripjjs Institute of Oceanography's Vermilion Sea 

 Expedition. Some 5000 miles of continuous data were obtained, the coverage in 

 the central part of the gulf being shown in Fig. 9 to indicate the detail obtainable 



Fig. 9. Gravity coverage in central section of Gulf of California obtained on Vermilion 

 Sea Expedition in the spring of 1959. 



with this instrument under favorable conditions. Simultaneous measurements 

 were taken with a LaCoste-Romberg underwater meter on the sea floor and 

 with the surface meter at 27 anchored stations. Surface measurements were 

 also made with Horizon anchored as close as possible (normally within 400- 

 1000 yds) to the shore, and a landing party sent ashore to make a simultaneous 

 measurement with a geodetic land meter. Navigational vmcertainties are 

 eliminated from these comparisons and the results, shown in Table I, indicate 

 an accuracy of 2-3 mgal for the surface measurements. The meter has also been 



