490 THE BELL SYSTEM TECHNICAL JOURNAL, APRIL 1951 



W. L. TuFFNELL, B.S. in Electrical Engineering, University of Wisconsin, 

 1930. Bell Telephone Laboratories, 1922-27; 1930-. Until 1949 Mr. Tuffnell 

 was chiefly concerned with the development of telephone instruments, and 

 since then with the development of other station apparatus as Station Ap- 

 paratus Development Engineer. 



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

 University, 1937. Bell Telephone Laboratories, 1937-. Mr. van Roosbroeck'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. 



R. L. Wallace, Jr., B.A., The University of Texas, 1936; M.A., The 

 University of Texas, 1939; graduate study at Harvard University, 1937-40. 

 During the recent war Mr. Wallace was a special Research Associate at 

 Harvard University, where he worked on military communications prob- 

 lems. Since he came to work for the Bell Telephone Laboratories in 1946 he 

 has been concerned with some problems in magnetic recording and with 

 transistors. 



