Contributors to this Issue 



A. J. Christopher, B.S. in E.E., Carnegie Institute of Technology, 

 1921; Engineering Department, Western Electric Company, 1921- 

 25; Bell Telephone Laboratories, 1925-. Mr. Christopher has been 

 engaged in voice and carrier frequency transformer design and more 

 recently concerned with the development of repeating, retardation, 

 and induction coils. 



A. B. Clark, B.E.E., University of Michigan, 1911 ; American Tele- 

 phone and Telegraph Company, 191 1-. Toll Transmission Develop- 

 ment Engineer, 1928-. Mr. Clark's work has been largely concerned 

 with toll telephone and telegraph systems. 



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

 of Paris, 1911-12; University of Berlin, 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. J. Davisson, B.Sc, University of Chicago, 1908; Ph.D., Princeton 

 University, 1911; Instructor in Physics, Carnegie Institute of Tech- 

 nology, 1911-17; Engineering Department of the Western Electric 

 Company, 1917-25; Bell Telephone Laboratories, 1925-. Dr. Davis- 

 son's work since coming with the Bell System has related largely to 

 thermionics and electronic physics. 



Bancroft Gherardi, B.Sc, Polytechnic Institute, Brooklyn, N. Y., 

 1891; M.E., Cornell University, 1893; M.M.E., Cornell University, 

 1894. New York Telephone Company, Engineering Assistant, 1895- 

 99; Traffic Engineer, 1899-1900. New York and New Jersey Tele- 

 phone Company, Chief Engineer, 1900-06. New York Telephone 

 Company, and New York and New Jersey Telephone Company, 

 Assistant Chief Engineer, 1906-07. American Telephone and Tele- 

 graph Company, Equipment Engineer, 1907-09; Engineer of Plant, 

 1909-18; Acting Chief Engineer, 1918-19; Chief Engineer, 1919-20; 

 Vice President and Chief Engineer, 1920-. Mr. Gherardi is a Past 

 President of the American Institute of Electrical Engineers and is now 

 President of the American Standards Association. 



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