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VOLUME XVn JULY, 1938 NUMBER 3 



THE BELL SYSTEM 



TECMSflCAL JOURNAL 



DEVOTED TO THE SCIENTIFIC AND ENGINEERING ASPECTS 

 OF ELECTRICAL COMMUNICATION 



Hertz, the Discoverer of Electric Waves — Julian Blanchard , 327 



Instruments for the New Telephone Sets — W, C. Jones . , 338 



Transmission Features of the New Telephone Sets 



—il. H, Inglis 358 



Spectrochemical Analysis in Communication Research 



—Beverly L. Clarke and A. E. Ruehle 381 



High Speed Motion Picture Photography — W. Herriott . . . 393 



An Optical Harmonic Analyzer — H. C. Montgomery .... 406 



Magnetic Shielding of Transformers at Audio Frequencies 



—W. G, Gustafson 416 



Coaxial Cable System for Television Transmission 



— M. E. Strieby 438 



Stabilized Feedback Oscillators — G. H, Stevenson .... 458 



The Discovery of Electron Waves — C. J. Davisson .... 475 



Abstracts of Technical Papers 483 



Contributors to this Issue 486 



AMERICAN TELEPHONE AND TELEGRAPH COMPANY 



NEW YORK 



iOc per Copy $1,50 per Year 



