MAJOR ACCOMPUSHMENTS 79 



GEOPHYSICAL INSTRUMENTS AND SYSTEMS 



Among the many instruments that have been developed in 

 the course of research programs, the geophysical instruments 

 for making measurements of elastic waves, magnetic fields, and 

 gravity fields have made outstanding contributions to the survey 

 and operational needs of the Navy. They also have enabled 

 progress to be made on a very wide front of geophysical in- 

 vestigations. 



Several significant geophysical instruments have been made 

 available for use in Navy programs, particularly survey pro- 

 grams. The early development in 1953 of precise echo sounders, 

 and subsequent progrsims for their improvement, were supported 

 by the Navy Ocean Science Program, as were the following other 

 instruments: sub-bottom echo sounders to determine the fine 

 structure of the upper layers of sediments; seismic-reflection 

 profilers to provide data on the thickness and grosser structures 

 of the sediment layers; seismic-refraction systems to furnish 

 data on the thickness and elastic-wave velocities of the crustal 

 and subscrustal layers; gravity meters, operated near the 

 center of least motion on surface ships and on submarines, to 

 provide data on variations in geological structures and bottom 

 topography; and magnetometers to provide measurements of 

 the total earth's field and of differences in the field. 



OCEANOGRAPHIC BUOYS 



The increased state of buoy technology that has developed 

 over the past several years has been a major accomplishment 

 of the Navy Ocean Science Program. This technology is necessary 

 for the development of oceanographic buoy systems for environ- 

 mental data collection in open ocean areas, particularly to meet 

 the needs of Navy environmental prediction systems. It includes 

 not only an improved understanding of the influencing factors 

 upon buoys, but also the hardware and deployment techniques 

 to be used in operational networks. 



The development of both drifting and moored buoys for re- 

 cording oceanographic data progressed slowly during the 1950's 



