THE BELL SYSTEM TECHNICAL JOURNAL 



Published quarterly by the 



American Telephone and Telegraph Company 



195 Broadway, New York 7, N. Y, 



Leroy A. Wilson Carroll O. Bickelhaupt Donald R. Belcher 



President Secretary Treasurer 



EDITORUL BOARD 



F. R. Kappel O. E. Buckley 



H. S. Osborne M. J. Kelly 



J. J. Pilliod A. B. Clark 



R. Bown D. A. Quarles 

 F. J. Feely 



J. O. Perrine, Editor P. C. Jones, Associate Editor 



SUBSCRIPTIONS 



Subscriptions are accepted at $1.50 per year. Single copies are 50 cents each. 

 The foreign postage is 35 cents per year or 9 cents per copy. 



PRINTED IN U. S. A. 



