THE BELL SYSTEM TECHNICAL JOURNAL 



ADVISORY BOARD 



A. B. GOETZE, President, Western Electric Company 



u. J. KELLT, President, Bell Telephone Laboratories 



E. J. McNEELY, Executive Vice President, American 

 Telephone and Telegraph Company 



EDITORIAL COMMITTEE 



B. MCMILLAN, Chairman k. e gould 



8. E. BRILLHART E. I. GREEN 



A. J. BUSCH R. K. HONAMAN 



L. R. COOK H. R. HUNTLEY 



A. C. DICKIE80N F. R. LACK 



R. L. DIETZOLD J. R. PIERCE 



EDITORIAL STAFF 



w. D. BULLOCH, Editor 



B. L. SHEPHERD, Production Editor 



T. N. POPE, Circulation Manager 



THE BELL SYSTEM TECHNICAL JOURNAL is published six times a year 

 by the American Telephone and Telegraph Company, 195 Broadway, New York 

 7, N. Y. F. R. Kappel, President; S. Whitney Landon, Secretary; John J. Scan- 

 Ion, Treasurer. Subscriptions are accepted at $5.00 per year. Single copies $1.25 

 each. Foreign postage is 65 cents per year or 11 cents per copy. Printed in U. S. A. 



