Abstracts of Technical Articles from Bell System Sources (01 October 1938)

Abstracts of Technical Articles from Bell System Sources 2 Proc. Nat'I. Acad. Sci., July 1938. Phys. Rev., September 15, 1938. 670 ABSTRACTS OF TECHNICAL ARTICLES 671 cal conductor there is a statistical variation of the electrical potential difference between its two ends which is due to the thermal agitation of the atoms, including the electrons. This electrical noise is amplified by means of a vacuum tube amplifier and then converted into an acoustical noise by means of a telephone receiver held on the ear. When this noise is present it reduces the capability of the ear to hear other sounds. 

The intensity per cycle of the acoustical noise compared to the intensity of a pure tone which can just be perceived in the presence of a noise was determined experimentally using a group of observers. This relative intensity for a given frequency range was constant throughout a wide variation of intensity. However, its value does vary with the position in the frequency spectrum and it is the amount of this variation which enables one to calculate the relation between the frequency of the tone and its position of maximum stimulation along the basilar membrane. 

The results of such a calculation are given and shown to be in good agreement with determinations from animal experimentation. Transcontinental Telephone Lines? J . J . PILLIOD. A fourth transcontinental line has just been created by the completion of four pairs of open wire between Oklahoma City and Whitewater, California. This open-wire line connects at its eastern terminus with the already existing toll cables from the east, and at its western terminus with a toll cable running into Los Angeles.