THE BELL SYSTEM TECHNICAL JOURNAL 



Published quarterly by the 



American Telephone and Telegraph Company 



195 Broadway, New York, N. Y. 



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EDITORIAL BOARD 



Bancroft Gherardi H. P. Charlesworth F. B. Jewett 



A. F. Dixon E. H. Colpitis O. B. Blackwell 



D. Levinger O. E. Buckley H. S. Osborne 



R. W. King, Editor J. O. Perrine, Associate Editor 



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SUBSCRIPTIONS 



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

 The foreign postage is 3S cents per year or 9 cents per copy. 



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Copyright, 1937 

 American Telephone and Telegraph Company 



PRINTED IN U. S. A. 



