Abstracts of Bell System Technical Papers Not 

 Appearing in this Journal 



The Communication System of the Conowingo Development} W. B. 

 Beals and E. B. Tuttle. This paper describes the communication 

 system which has been installed to serve the power plant at Conowingo, 

 Maryland, and its associated transmission line. 



The important features to be considered in designing a telephone 

 system for a power plant are pointed out. The types of telephone 

 switchboard and telephone instruments chosen in this case to meet the 

 special requirements of the generating station, together with the layout 

 and cabling arrangement, are outlined. 



The paper also discusses the possible ways of providing for the needs 

 of the load dispatcher and the plan adopted at Conowingo; the facilities 

 provided the patrolmen for calling from points along the transmission 

 line; the connection from the private branch exchange to the general 

 telephone system; and the special electrical protection installed on the 

 long lines leaving the power house. 



Reflection and Refraction of Electrons by a Crystal of Nickel." C. J. 

 Davisson and L. H. Germer. This is a report of further observations 

 on the regular reflection of electrons from the surface of a nickel 

 crystal; an earlier report was published in the same journal.^ In the 

 present report data are given of the selectivity of reflection for angles 

 of incidence from 10 to 50 degrees, and for electrons of wave-lengths 

 0.6 to 1.5 A. The previously found result is confirmed that to explain 

 the occurrence of the intensity maxima of the reflected beam it is 

 necessary to assume that electron waves are refracted on passing into 

 the crystal. The data are used for calculating indices of refraction for 

 nickel for electrons of various speeds or wave-lengths, and a dispersion 

 curve is constructed. This curve displays a feature suggestive of the 

 optical phenomenon of anomalous dispersion. 



Optical Experiments with Electrons} L. H. Germer. A semi- 

 popular account of a series of experiments performed by C. J. Davisson 

 and the author upon the scattering of electrons by single crystals of 



1 Journal of the A. I. E. E., October 1928, pp. 737-741. 



2 Proceedings of the National Academy of Sciences, August 1928, pp. 619-627. 

 ^Proceedings of the National Academy of Sciences, April 1928, pp. 317-322. 



* Journal of Chemical Education, Part I, Sept. 1928, pp. 1041-1055. Part II, Oct. 

 1928, pp. 1255-1271. 



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