CONTRIBUTORS TO THIS ISSUE 1039 



Frank Gray, B.S., Purdue, 1911; M.A., Wisconsin University, 1913; 

 Ph.D., 1916. U. S. Navy, 1917-19; Bell Telephone Laboratories, 1919- His 

 work has been chiefly research in microphone and relay contacts, gas dis- 

 charge tubes, television, electron beam tubes, microwave tubes, PCM sys- 

 tems, and transistors. Fellow of American Physical Society and the A.A.A.S.; 

 member of Gamma Alpha and Sigma XI; and Associate, I.R.E. 



R. D. Heidenreich, B.S., Case School of Applied Science, 1938; M.S., 

 1940. Dow Chemical Company, 1940-45; Bell Telephone Laboratories, 

 1945-. Here he has worked chiefly on problems of surface metallurgy. Fellow 

 of American Physical Society; member of A.A.A.S., the Electron Microscope 

 Society of America and Sigma Xi. 



A. N. HoLDEN, B.S., Harvard, 1925. Bell Telephone Laboratories, 1925-. 

 In the Research Department his work has been chiefly in chemistry and 

 solid state physics, primarily in originating new piezoelectric materials and 

 in perfecting methods of growing crystals. 



A. G. Jensen, E.E., Royal Technical College, Copenhagen, 1920; instruc- 

 tor, 1921. Bell Telephone Laboratories, 1922-. He has been occupied chiefly 

 in radio receiving studies, short-wave transatlantic telephony, coaxial cable 

 development and television research. Fellow of I.R.E. and member of Society 

 of Motion Picture and Television Engineers. 



M. J. Kelly, B.S., Missouri School of Mines and Metallurgy, 1914; M.S., 

 University of Kentucky, 1915; Ph.D., University of Chicago, 1918. Joining 

 Bell Telephone Laboratories in 1918, Dr. Kelly became Director of Vacuum 

 Tube Development in 1928; Director of Research, 1936; Executive Vice 

 President, 1944; President, 1951. For the past year he has also served in an 

 advisory capacity to the Air Force to assist in organizing its research and 

 development. He holds honorary doctors' degrees from the University of 

 Kentucky and the University of Missouri. In 1944 Dr. Kelly was awarded a 

 Presidential Certificate of Merit and in 1945 was elected to the National 

 Academy of Sciences. Member of Franklin Institute; Fellow of American 

 Physical Society, I.R.E., Acoustical Society of America, A.I.E.E., and the 

 American Association for the Advancement of Science. 



L. A. MacColl, A.B., University of Colorado, 1919; M A., Columbia, 

 1925; Ph.D., 1934. Bell Telephone Laboratories, 1919-. He has been con- 

 cerned chiefly with mathematical research and consultation. Visiting lec- 

 turer, Princeton, 1948-49 ; author of "Fundamental Theory of Servomecha- 



