612 BELL SYSTEM TECHNICAL JOURNAL 



Corps, A.E.F., 1917-19; Harvard, 1922-25; Bell Telephone Labo- 

 ratories, 1925-. Mr. Lack has been engaged in experimental work 

 connected with radio communication. 



W. A. Marrison, Royal Flying Corps, later Royal Air Force, 

 Canada, 1917-18; B.Sc, Queens University, Canada, 1920; A.M. 

 in Physics and Mathematics, Harvard University, 1921; Western 

 Electric Company, 1921-25; Bell Telephone Laboratories, 1925-. 

 Mr. Marrison is engaged in the study of picture transmission and 

 methods for the production of constant frequency. 



W. H. Martin, A.B., Johns Hopkins University, 1909; B.Sc, 

 Massachusetts Institute of Technology, 1911; American Telephone 

 and Telegraph Company, Engineering Department, 1911-19; Depart- 

 ment of Development and Research, 1919-. Mr. Martin's work has 

 related particularly to transmission of telephone sets and local ex- 

 change circuits, transmission quality and loading. 



W. O. Pennell, B.Sc, Massachusetts Institute of Technology, 

 1896; Instructor, Lafayette College, 1896-1898; Equipment and 

 Traffic Engineer, Bell Telephone Company of Philadelphia, 1898-1902; 

 Engineering Department, American Telephone and Telegraph Com- 

 pany, 1902-03; Chief Engineer, Missouri and Kansas Telephone 

 Company, 1903-12; Southwestern Bell Telephone Company, 1912- 

 29, and for the last eleven years their Chief Engineer. In addition 

 to his activities as an engineer, Mr. Pennell has from time to time 

 contributed articles of a mathematical nature to various technical 

 publications. 



J. R. TowNSEND, Engineering Department, Western Electric Com- 

 pany, 1919-25; Bell Telephone Laboratories, 1925-. Mr. Townsend 

 has been largely concerned with the testing of telephone apparatus 

 and more recently with the development of requirements of test for 

 metallic materials. 



