VOLUME XIV JULY, 1935 NUMBER 3 



THE BELL SYSTEM 



I TECHNICAL JOURNAL 



DEVOTED TO THE SCIENTIFIC AND ENGINEERING ASPECTS 

 OF ELECTRICAL COMMUNICATION 



Further Results of a Study of Ultra-Short-Wave Trans- 

 mission Phenomena — 

 C. R. Englund, A. B. Crawford and W. W. Mumford 369 



Acoustical Instruments — E. C. Wente 388 



Thermionic Electron Emission — J. A. Becker . . . 413 



Radio Propagation Over Spherical Earth — 



Chas. R. Burrows 477 



A Single-Sideband Short-Wave System for Trans- 

 atlantic Telephony — 



F. A. Polkinghorn and N. F. Schlaack 489 



Mutual Impedances of Parallel Wires — 



Ray S. Hoyt and Sallie Pero Mead 509 



An Unattended Ultra-Short-Wave Radio Telephone 



System — N, F. Schlaack and F. A. Polkinghorn 534 



Around the World by Telephone 542 



Abstracts of Technical Papers 544 



Contributors to this Issue 550 



AMERICAN TELEPHONE AND TELEGRAPH COMPANY 



NEW YORK 



50c per Copy $1.50 per Year 



