THE BELL SYSTEM 



TECHNICAL JOURNAL 



VOLUME IX, 1930 



TABLE OF CONTENTS 



January, 1930 



Telephone Communication System of the United States — 



Bancroft Gherardi and F. B. Jcivett 1 



Structure and Nature of Troostite — Francis F. Lucas 101 



Radio Broadcasting Transmitters and Related Transmission Phe- 

 nomena — Edzvard L. Nelson 121 



Wire Line Systems for National Broadcasting — A. B. Clark 141 



Notes on the Heaviside Operational Calculus — John R. Carson ... 150 



Contemporary Advances in Physics, XIX — Karl K. Darroiv 163 



Wave Propagation Over Continuously Loaded Fine Wires — 



M. K. Zinn 189 



Theory of Vibration of the Larynx — R. L. Wegel 209 



April, 1930 



Developments in Communication Materials — William Fondillcr . . . 237 



Transoceanic Telephone Service — Short- Wave Transmission — 



Ralph Bown 258 



Transoceanic Telephone Service — -Short-Wave Equipment — 



A. A. Oszvald 270 



The \\^ords and Sounds of Telephone Conversations — Norman R. 



French, Charles W. Carter, Jr., and Walter Koenig, Jr 290 



The Reciprocal Energy Theorem — John R. Carson 325 



The Approximate Networks of Acoustic Filters — W. P. Mason . . 332 



Contemporary Advances in Physics, XX — Karl K. Darrow 341 



Motion of Telephone Wires in Wind — D. A. Quarks 356 



Economic Quality Control of Manufactured Product — 



W. A. Shewhart 364 

 Optimum Reverberation Time for Auditoriums — 



Walter A. MacNair 390 

 3 





