Contributors to this Issue 



Edwin H. Colpitts was introduced to readers of the Journal — if it 

 can be said that he needed an introduction — in the April issue. 



Karl K. Darrow, B.S.. University of Chicago, 1911; University of 

 Paris, 1911-12; University of BerHn, 1912; Ph.D., University of 

 Chicago, 1917. Western Electric Company, 1917-25; Bell Telephone 

 Laboratories, 1925-. Dr. Darrow has been engaged largely in writing 

 on various fields of physics and the allied sciences. 



C. B. Feldman, B.Sc, University of Minnesota, 1926; Teaching 

 Fellow, University of Minnesota, 1926-28; M.Sc, University of Minne- 

 sota, 1928. Bell Telephone Laboratories, 1928-. Mr. Feldman has 

 been engaged in short-wave radio receiving. His work has been mainly 

 on transmission lines, antennas, and wave propagation problems. 



H. T. Friis, E.E., Royal Technical College in Copenhagen, 1916; 

 Columbia University, 1919-20. Research Department, Western 

 Electric Company, 1920-24; Bell Telephone Laboratories, 1925-. 

 Mr. Friis' work has been largely in connection with radio reception 

 methods and measurements. He has published papers on vacuum 

 tubes as generators, radio transmission measurements and static 

 interference. As Radio Research Engineer he now directs studies of 

 new methods of short-wave reception. 



W. P. Mason, B.S. in Electrical Engineering, University of Kansas, 

 1921 ; M.A., Columbia University, 1924; Ph.D., 1928. Bell Telephone 

 Laboratories, 192 1-. Dr. Mason has been engaged in investigations 

 on carrier transmission systems and more recently in work on wave 

 transmission networks, both electrical and mechanical. 



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. 



R. A. Sykes, Massachusetts Institute of Technology, B.S. 1929; 

 M.S. 1930. Columbia University, 1931-33. Bell Telephone Labora- 

 tories, Research Department, 1930-. Mr. Sykes has been engaged in 

 the application of piezoelectric crystals to selective networks, and 

 more recently in the use of coaxial lines as filter elements. 



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