392 BELL SYSTEM TECHNICAL JOURNAL 



Laboratories, 1934-. Mr. Ilgenfritz has been engaged in the develop- 

 ment of carrier systems. 



A. G. Johnson, B.S. in Ceramic Engineering, Iowa State College, 

 1924. Western Electric Company, Development Engineering Branch, 

 1924-. Prior to October 1935, Mr. Johnson was engaged in develop- 

 ment work on ceramic, rubber, phenol fibre, and plastic molding 

 manufacture. At the present time, he is Engineer of Raw Materials 

 at the Hawthorne Plant, Chicago, Illinois. 



Frederick B. Llewellyn, M.E., Stevens Institute of Technology, 

 1922; Ph.D., Columbia University, 1928. Western Electric Com- 

 pany, 1923-25; Bell Telephone Laboratories, 1925-. Dr. Llewellyn 

 has been engaged in the investigation of special problems connected 

 with high-frequency circuits and vacuum tubes. In his present 

 capacity as Circuit Research Engineer he directs a group in the study 

 of amplifying problems. 



J. D. Mathis, B.A., University of Texas, 1924; M.A., University 

 of Texas, 1925; Tutor in Physics at University of Texas, 1924-25. 

 Telephone equipment maintenance, 1920-24. Southwestern Bell 

 Telephone Company, equipment engineering, 1925-. Since 1932 

 Mr. Mathis has been engaged principally in the engineering of central 

 office equipment for telephone repeaters and carrier systems in Texas. 



John Riordan, B.S., Sheffield Scientific School, Yale University, 

 1923. American Telephone and Telegraph Company, Department of 

 Development and Research, 1926-34; Bell Telephone Laboratories, 

 1934-. Mr. Riordan 's work has been mainly on problems associated 

 with inductive effects of electrified railways. 



L. I. Shaw, B.S. in Ceramics, Alfred University, 1907; M.S., 

 Syracuse University, 1908; Ph.D., University of Wisconsin, 1911; 

 Instructor, Northwestern University, 1911-17; Assistant Chief Chem- 

 ist, U. S. Bureau of Mines, 1919-24. Western Electric Company, 

 Hawthorne Plant, Chicago, Illinois, 1924-. As Development Engi- 

 neer, Dr. Shaw's work has been largely in the fields of ceramics, 

 chemistry, hazards, and raw materials. 



L. C. Starbird, B.E.E., University of Arkansas, 1921; Instructor, 

 University of Arkansas, 1921-25. Southwestern Bell Telephone 

 Company, 1925-; Equipment Engineer, 1926-32, Transmission and 

 Protection Engineer, Texas Area, 1932-. Mr. Starbird's work has 

 been largely in the application of carrier and repeater equipment. 



