Hydrographic Office for his close cooperation and assistance in nearly all phases of 

 the study after May 1958, and to my colleagues at the Navy Electronics Laboratory 

 for helpful discussions on different aspects of the investigation. I also thank the 

 numerous individuals who helped in the compilation of the data tables, performed 

 typing, and drafted the final illustrations. 



The report was written while I was a National Academy of Sciences-National 

 Research Council Postdoctoral Resident Research Associate at the U.S. Navy 

 Electronics Laboratory in San Diego, California.''' I am pleased to acknowledge the 

 cheerful support of many persons at the laboratory, especially Dr. E. L. Hamilton, 

 my advisor, for his continued encouragement. 



A preliminary draft of this paper was reviewed by Mr. P. P. Brown, Dr. G. H. 

 Curl, Dr. E. L. Hamilton, Mr. G. H. Keller, Dr. R. T. Martin, Mr. D. G. Moore, 

 Dr. G. Shumway, and Mr. C. M. Yeomans, to whom I am appreciative for helpful 

 suggestions . 



* Author Js presently a member of the staff of Office of Naval Research Branch Office, 

 American Embassy, London, England. 



