CONTRIBUTORS 675 



J. R. Pierce, B.S. in Electrical Engineering, California Institute of Tech- 

 nology, 1933; Ph.D., 1936. Bell Telephone Laboratories, 1936-. Dr. Pierce 

 has been engaged in the study of vacuum tubes. 



Robert M. Ryder, Yale University, B.S. in Physics, 1937; Ph.D., 1940. 

 Bell Telephone Laboratories, 1940-. Dr. Ryder joined the Laboratories to 

 work on microwave amplifier circuits, and during most of the war was a 

 member of a group engaged in studying the signal-to-noise performance of 

 radars. In 1945 he transferred to the Electronic Development Department 

 to work on microwave oscillator and amplifier tubes for radar and radio 

 relay applications. He is now in a group engaged in the development of 

 transistors. 



W. VAN RoosBROECK, A.B., Columbia College, 1934; A.M., Columbia 

 University, 1937. Bell Telephone Laboratories, 1937-. Mr. van Roos- 

 broeck's work at the Laboratories was concerned during the war with carbon- 

 film resistors and infra-red bolometers and, more recently, with the copper 

 oxide rectifier. In 1948 he transferred to the Physical Research Department 

 where he is now engaged in problems of solid-state physics. 



