772 THE BELL SYSTEM TECHNICAL JOURNAL, JULY 1951 



Means of a Network Representing the Basilar Membrane* B. P. Bogert^ 

 Acoustical Soc. Am., JL, v. 23, pp. 151-154, Mar., 1951. 



Abstract — Results are given of measurements made on a 175-section net- 

 work representing the basilar membrane, which was modified to include the 

 effects of dissipation in the cochlear partition. The results show that the 

 dynamical theory of the cochlea, when dissipation is considered, is in good 

 agreement with experimental evidence. 



A Professional Magnetic-Recording System for Use With 35-, 17^- and 

 16-Mm Films. G. R. Crane^, J. G. FrayneS and E. W. Templin^ S.M.P.E., 

 JL, V. 56, pp. 295-309, Mar., 1951. 



Abstract — This paper describes a portable magnetic-recording system 

 for producing high-quality sound tract in synchronism with pictures. The 

 system has been designed to enable magnetic recording to conform with 

 standard motion picture studio operating practices. A number of features 

 such as high-speed rewind, interlocked-switching facilities, one basic type of 

 amplifier and the use of miniature tubes throughout have been incorporated 

 in the system. 



Additional Continuous Sampling Inspection Plans.* H. F. Dodge^ and 

 M. N. TorreyK Ind. Quality Control, v. 7, pp. 7-12, Mar., 1951. 



The Mobility and Life of Injected Holes and Electrons in Germanium.* 

 J. R. Haynes^ and W. Shockley^ Bibliography. Phys. Rev., v. 81, pp. 

 835-843, Mar. 1, 1951. 



Abstract — The mobilities of holes injected into n-type germanium and 

 of electrons injected into p-type germanium have been determined by 

 measuring transit times between emitter and collector in single crystal rods. 

 Strong electric fields in addition to those due to injected current were em- 

 ployed so that spreading effects due to diffusions were reduced. The mobili- 

 ties at 300°K are 1700 cmV volt-sec for holes and 3600 cmV volt-sec for 

 electrons with an error of probably less than five percent. The value for 

 electrons is about 20 percent higher than the best estimates obtained from 

 the conventional interpretation of the Hall effect and the difference may be 

 due to curved energy band surfaces in the Brillouin zone. Studies of rates 

 of decay indicate that recombination of holes and electrons takes place 

 largely on the surface of small samples with constants varying from 10^ to 

 > 10^ cm/sec for special treatments. 



On the Theory of Spin Waves in Ferromagnetic Media.* C. Herring^ and 

 C. Kittel^. Bibliography. Phys. Rev., v. 81, pp. 869-880, Mar. 1, 1951. 



Abstract — The theory of spin waves, leading to the Bloch T^ law for the 



* A reprint of this article may be obtained on request. 

 ' B. T. L. 



* Westrex Corp. 



