use in the proposed geophysical data collection system and to meet 

 other interim requirements for continuous temperature measurements. 



F. SALINITY MEASUREMENTS 



It is the conclusion of the Committee that development of a satis- 

 factory in situ salinometer for deep water oceanography is not in 

 prospect for the immediate future. Therefore, it is felt that some 

 effort should be devoted toward reducing the size of, and otherwise 

 improving, the conductivity bridge for shipboard use and possible 

 use on submarines. The compact, high-performance salinometer 

 developed by the Australians should be thoroughly tested and compared 

 with other available salinometer s. 



A possible means for speeding up the collection of water samples 

 was suggested in the second progress report of this Committee 

 (Appendix B). This suggestion was for precise triggering of a multiple 

 sea sampler at standard depths as indicated by a vibrating wire 

 transducer or other good depth element. Triggering can be done either 

 automatically, or manually when the proper depth is indicated by a 

 depth recorder. By coupling this with an accurate temperature element, 

 further speed-up could be achieved. After a satisfactory depth element 

 has been obtained and accepted for field use, a prototype of this system 

 should be built. 



The use of interferometers and beta absorption techniques for 

 salinity determinations should be explored further, and development 

 of the Induction Conductivity Indicator for use in coastal waters should 

 be continued. Additional information should be obtained on the in situ 

 salinometers developed in West Germany for the University of Kiel, and 

 the possibility and advisability of purchasing one of these instruments 

 should be explored. 



G. PRESSURE (DEPTH) MEASUREMENTS 



It is difficult to draw any definite conclusions concerning the accu- 

 racies of various depth gauges because of the lack of adequate facilities 

 for running comparative tests. Inasmuch as the measurement of depth 

 is an essential part of nearly all oceanographic determinations, selec- 

 tions from, existing devices must be made. On the basis of such evidence 

 as exists, the vibrating wire transducer appears to give the most 

 dependable measurements of depth, both in shallow and deep water. 

 However, it is slightly higher in cost and somewhat more complex 

 than other available instruments. The greatest area of doubt concern- 

 ing the accuracy of this instrument is in establishing the effect of 



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