THE BELL SYSTEM TECHNICAL JOURNAL 



Published quarterly by the 

 American Telephone and Telegraph Company 

 195 Broadway, New York, N. Y. . 



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EDITORS 

 R. W. King J. O. Perrine 



F. B. Jewett 

 A. B. Clark 

 S. Bracken 



EDITORIAL BOARD 



H. P. Charlesworth 



O. E. Buckley 



M. J. Kelly 



W. Wilson 



W. H. Harrison 

 O. B. Blackwell 

 G. Ireland 



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SUBSCRIPTIONS 



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

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



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Copyright, 1940 

 American Telephone and Telegraph Company 



PRINTED IN U. 8. A. 



