

VOLUME XXIX OCTOBER, 1950 no. 4 



THE BELL SYSTEM 



TECHNICAL JOURNAL 



DEVOTED TO THE SCIENTIFIC AND ENGINEERING ASPECTS 

 OF ELECTRICAL COMMUNICATION 



«*ubiJc Library 



Kansas City, |J1 



Theory of Relation between Hole Concentration and Char- 

 acteristics of Germanium Point Contacts . .. /. Bardeen 469 



Design Factors of the Bell Telephone Laboratories 1553 



Triode J. A. Morton and R. M. Ryder 496 



A New Microwave Triode : Its Performance as a Modulator 

 and as an Amplifier 



A. E. Bowen and W. W. Mumford 531 



A Wide Range Microwave Sweeping Oscillator 



M. E. Hines 553 



Theory of the Flow of Electrons and Holes in Germanium 



and Other Semiconductors W. van Roosbroeck 560 



Traveling- Wave Tubes [Fourth Installment] ./. /2. Pierce 608 



Technical Publications by Bell System Authors Other than 



in the Bell System Technical Journal 672 



Contributors to this Issue 674 



30i Copyright, 1950 $1.50 



per copy American Telephone and Telegraph Company per Year 



