Navy problems o They had collected a substantial quantity of 

 data , not only on underwater sound transmission, but also on 

 relevant oceanographic problems „ They had developed the bathy- 

 thermograph, a device to make a record of water temperatures 

 at all depths down to 300 or 400 feeto The bathythermograph 

 had been perfected to the point where it could be used for 

 temperature -depth measurements from vessels under way at 15 

 or 20 knots o They had developed applications of the refrac- 

 tion theory to underwater sound and while this theory was 

 necessarily over-simplif ied^ it proved extremely important 

 in the interpretation of later information,, In 1940 y there- 

 fore 9 as already mentioned, NDRC entered into. a contract with 

 the Woods Hole Oceanographic Institution,, 



In the spring of 1941 s in the light of further demands 

 from the Navy^, it became clear that the Woods Hole staff could 

 not carry on alone „ Not only was there need for more help p 

 but it was felt that there should be a place where research 

 work could be done at a location close to a large Navy estab- 

 lishment and near deep water, which the shallow Atlantic con- 

 tinental shelf made relatively inaccessible „ San Diego seemed 

 an excellent site since the 600=fathonr San Diego Trough is 

 located only 15 miles off-shore NDRCj, therefore 9 entered in- 

 to a contract with the University of California for the estab- 

 lishment of an additional research group at the U„ So Navy 

 Radio and Sound Laboratory (now the U„ So Navy Electronics 

 Laboratory) at San Diego „ The University of California's 

 program as it developed drew a considerable measure of assis- 

 tance from the Scripps Ooeanographic Institution at La Jolla 



When experimental results began to accumulate from the 

 work of the Woods Hole and University of California groups^ 

 it became desirable to assign a small staff of physicists and 

 mathematicians to the analysis and evaluation of these re- 

 search resultSo Employed under a contract with Columbia Uni- 

 versity 9 these scientists became known as the Sonar Analysis 

 Group,, Working in close cooperation with Interested sections 

 of the Navy, this group combined the basic research results 

 obtained by different groups and determined the bearing of the 

 research findings upon problems of design and operation,, 



The over-all program divided itself naturally into a num- 

 ber of fields of research; one of the principal studies being 

 that of Underwater Sound Transmission,, 



24 



