V 



THE BELL SYSTEM 



TECHNICAL JOURNAL 



A JOURNAL DEVOTED TO THE 



SCIENTIFIC AND ENGINEERING 



ASPECTS OF ELECTRICAL 



COMMUNICATION 



Bancroft Gherardi 

 L. F. Morehouse 

 D. Levinger 



EDITORIAL BOARD 



H. P. Charles WORTH 



E. H. COLPITTS 



O. E. Buckley 



F. B. Jewett 



O. B. Blackwell 



H. S. Osborne 



Philander Norton, Editor 



J. O. Perrine, Associate Editor 



TABLE OF CONTENTS 



AND 



INDEX 

 VOLUME XII 



1933 



AMERICAN TELEPHONE AND TELEGRAPH COMPANY 



NEW YORK 



