THE BELL SYSTEM 



TECHNICAL JOURNAL 



A JOURNAL DEVOTED TO THE 



SCIENTIFIC AND ENGINEERING 



ASPECTS OF ELECTRICAL 



COMMUNICATION 



EDITORIAL BOARD 



J. J. Carty Bancroft Gherardi F. B. Jewett 



E. B. Craft L. F. Morehouse O. B. Blackwell 



H. P. Ciiarli-.sworth E. H. Colpitts H. D. Arnold 



R. W. KiSG^Ediior ]. O. Perrixe— .^^^f. Editor 



VOLUME V 

 1926 



AMERICAN TELEPHONE AND TELEGRAPH COMPANY 



NEW YORK 



