Abstracts of Technical Articles by Bell System Authors 



Audio-Frequency Measuremenls} f W. L. Black* and H. H. Scott. This 

 paper indicates the theory involved in making measurements of gain, fre- 

 quency response, distortion, and noise at audio frequencies, with particular 

 emphasis on such measurements made on high-gain systems. There are 

 also discussed techniques of measurement and factors affecting the accu- 

 racy of results. This subject is not new art but has not previously been 

 pubUshed in correlated form, to the knowledge of the authors. 



Growing Quartz Crystals} f E. Buehler and A. C. Walker. The Bell 

 Telephone Laboratories started an investigation of this subject in March 

 1946, based on information gleaned from several investigators who visited 

 Germany after the war, particularly Mr. J. R. Townsend of these Labora- 

 tories, and Professor A. C. Swinnerton of Antioch College. After a relatively 

 few experiments made with equipment similar to that used by Professor 

 Richard Nacken in Germany, and with the process he described, it became 

 apparent that Nacken had made substantial progress in the art of growing 

 quartz at temperatures and pressures near the critical state of water, i.e., 

 about 374°C, and 3,200 pounds per square inch. This report summarizes 

 further progress that has been made in the Laboratories since March 1946. 



Corrosion of Telephone Outside Plant Material} f K. C. Compton and 

 A. Mendizza. Problems resulting from corrosion in the telephone outside 

 plant are many and varied. In this article an attempt is made to give a 

 broad overall picture of these problems and the manner in which they are 

 met and solved by the telephone plant engineer. 



Magnetic Recording in Motion Picture Techniques} John G. Frayne and 

 Halle Y Wolfe. Development of magnetic recording at the Bell Telephone 

 Laboratories is described with the application of such facilities to Western 

 Electric recording and reproducing systems. A method of driving 35-mm. 

 magnetic film with a flutter content not greater than 0.1 per cent is de- 

 scribed, as is a multigap erasing head. 



Semi-Conducting Properties in Oxide Cathodes} f N. B. Hannay, D. 

 MacNair, and A. H. White. It has been widely assumed, without ade- 



' Proc. I. R. E., V. 37, pp. 1108-1115, October 1949. 

 * Of Bell Tel. Labs. 



^Sci. Monllily, v. 69, pp. 148-155, September 1949. 

 ^Corrosion, v. 5, pp. 194-197, June 1949. 

 ".S". M. P. E. Jour., V. 53, pp. 217-234, September 1949. 

 "•Jour. Applied Pliysics, v. 20, pp. 669-681, July 1949. 



t A reprint of this article may be obtained by writing to llie Editor of the Bell System 

 Technical Journal. 



142 



