THE BELL SYSTEM 



TECHNICAL JOURNAL 



A JOURNAL DEVOTED TO THE 



SCIENTIFIC AND ENGINEERING 



ASPECTS OF ELECTRICAL 



COMMUNICATION 



EDITORIAL BOARD 



]. ]. Carty Bancroft Giikrardi F. B. Jew in t 



E. B. Craft L. F. Morehousi: O. B. Blackuell 



H. P. CHARLESWORTH IC. H. COLPITTS H. D. ARNOLD 



R. W. Kin.,— ErfiVor T. O. Pi;rrine~.;.w/. Editor 



VOLUME IV 

 1925 



AMERICAN TELEPHONE AND TELEGRAPH COMPANY 

 NEW YORK 



