VOLUME XVI APRIL, 1937 ^aJMBER2 



THE BELL SYSTEM 



TECHNICAL JOURNAL 



DEVCEED TO THE SCIENTIFIC AND ENGINEERING ASPECTS 

 OF ELECTRICAL COMMUNICATION 



Recent Trends in Toll Transmission in the United States — 



Edwin H. Colpitis 119 



Crosstalk Between Coaxial Transmission Lines — 



S. A. Schelkunoff and T. M, Odarenko 144 



Sound Recording on Magnetic Tape — C. N. Hickman . . . 165 



Constant Resistance Networks with Applications to Filter 



Groups — E, L. Norton 178 



A Laboratory Evaluation of Wood Preservatives — 



R, E, Waterman, John Leutritz and Caleb M, Hill 194 



Study of Magnetic Losses at Low Flux Densities in Permalloy 

 Sheet— PF. B. Ellwood and V. E, Legg 212 



Moisture in Textiles — Albert C. Walker 228 



Abstracts of Technical Papers 247 



Contributors to this Issue 249 



AMERICAN TELEPHONE AND TELEGRAPH COMPANY 



NEW YORK 



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