VI PREFACE 



for facilities and secretarial assistance ; and particularly to Professors 

 Jay W. Woodrow, Gerald W. Fox and Percy H. Carr for their en- 

 couragement. At the Navy Electronics Laboratory, the cooperation 

 of Dr. R. J. Christensen has been very helpful. 



Navy Electronics Laboratory Fred M. LTber 



San Diego, California 

 December, 1949 



