CONTRIBUTORS 489 



President, Mr. Martin has been associated in various capacities with the 

 work on telephone instruments and sets since 1918. He has participated also 

 in the development and application of these and allied devices in the fields 

 mentioned in the Conclusion section of his paper. 



W. P. Mason, B.S. in E.E., University of Kansas, 1921; M.A., Ph.D., 

 Columbia, 1928. Bell Telephone Laboratories, 192 1-. Dr. Mason has been 

 engaged principally in investigating the properties and applications of 

 piezoelectric crystals and in the study of ultrasonics. 



L. Pedersen, graduate of Christiania Technical School, 1919. Western 

 Electric International, 1919-20. Bell Telephone Laboratories, 1920-. Prior 

 to World War II Mr. Pedersen was engaged chiefly in the development of 

 d-c. telegraph equipment. During the war he was engaged in the design of 

 the Spiral-Four carrier equipment and served with the U. S. Army in the 

 European Theatre of Operation as a technical observer. Since the war his 

 principal activities have been as equipment engineer for the N-1 and O 

 Carrier telephone development. 



A. C. Pfister, B.M.E., Brooklyn Polytechnic Institute, 1939. Bell Tele- 

 phone Laboratories, 1930-. In the Physical Research, Electronic Apparatus 

 Development, and Transmission Apparatus Development Departments, 

 Mr. Pfister has been engaged in research and development on microphone 

 carbon and deposited carbon resistors. 



Gordon Raisbeck, Massachusetts Institute of Technology, 1941-43; 

 teaching fellow, Stanford University, 1943-44; B.A. in pure mathematics, 

 1944; Radio Technical Officer, U. S. Navy, 1944-46; instructor in mathe- 

 matics, M.I.T., 1946-47; Rhodes Scholar, New College, Oxford, 1947-48; 

 instructor in mathematics, M.I.T., 1948-49; Ph.D. in pure mathematics, 

 1949. Bell Telephone Laboratories, 1949-. Mr. Raisbeck is in the Trans- 

 mission Research Department and is engaged in the study of acoustics and 

 acoustical devices. 



Thomas Shaw, S.B., Massachusetts Institute of Technology, 1905. 

 American Telephone and Telegraph Company, Engineering Department, 

 1905-19; Department of Development and Research, 1919-33. Bell Tele- 

 phone Laboratories, 1933-48. Mr. Shaw's active telephone career was 

 mainly concerned with loading problems in telephone circuits, including the 

 transmission and economic features of the loading apparatus. The article 

 now being published was started shortly before his retirement in 1948. 



