Contributors to this Issue 



H. S. Black, B.S. in Electrical Engineering, Worcester Polytechnic 

 Institute, 1921. Western Electric Company, Engineering Depart- 

 ment, 1921-25; Bell Telephone Laboratories, 1925-. Mr. Black's 

 work has had to do with the development of carrier telephone systems. 



Arthur G. Chapman, E.E., University of Minnesota, 1911. Gen- 

 eral Electric Company, 1911-13. American Telephone and Telegraph 

 Company, Engineering Department, 1913-19, and Department of 

 Development and Research, 1919-. Mr. Chapman is in charge of a 

 group engaged in developing methods for reducing crosstalk between 

 communication circuits, both open wire and cable, and evaluating 

 effects of crosstalk on telephone and other services. 



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. 



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

 1922 ; Ph.D., Columbia University, 1928. Western Electric Ccvmpany, 

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

 engaged in the investigation of special problems connected with radio 

 and vacuum tubes. 



161 



