688 BELL SYSTEM TECHNICAL JOURNAL 



Theoretical and Practical Aspects of Directional Transmitting Systems.^ 

 E. J. Sterba. This paper discusses some of the more important prin- 

 ciples involved in the development of the directional transmitting 

 antennas at present employed in the Bell System short-wave facilities. 

 The theoretical performance of directive arrays is presented by means 

 of various curves which have been obtained by integrations based upon 

 Poynting's theorem. The details of the mathematical derivations are 

 omitted for the sake of brevity, but the general procedure and the re- 

 sulting formulas have been placed in an appendix. Various practical 

 problems encountered in the development are described. These 

 include antenna tuning procedure, transmission line adjustments, and 

 sleet melting facilities. 



Nature of Stimulation at the Organ of Corti in the Light of Modern 

 Physical Experimental Data.^ R. L. Wegel. The active prosecution 

 of a program for the study of deafness has arrived at a point where a 

 correct understanding of the mechanism of hearing may be utilized 

 with profit. A "theory" should not be regarded as an academic de- 

 scription in terms of mathematical symbols of what is conceived to be a 

 correct and final solution of the problem. It should be regarded as 

 a necessary correlation of experimental data. The "correctness" 

 of the theory should be judged by its utility and as long as it satisfies 

 all demands made on it there is nothing "wrong" with it. The most 

 that can be asked of any theory is that new experimental data, as it 

 appears from time to time, will modify the conclusions only in quanti- 

 tative detail but not in its broader qualitative aspects. The principal 

 value of a theory is in the practical use that can be made of it, the 

 value of it as an intellectual exercise being negligible. 



The "theory" of hearing which apparently is in accord with all ex- 

 perimental data, whether it be anatomical, physiological or physical, 

 is that which in its rudimentary form is known as the Helmholtz 

 theory. Owing to the existence at present of a large quantity of precise 

 data, particularly of a physical nature, this theory has undergone con- 

 siderable advance since the time of Helmholtz. 



Briefly, this theory ascribes the principal part of sound analysis to 

 the mechanical properties of the end organ. In order to accept the 

 essential points it is necessary to be agreed on a limited number of 

 specific points: 



1. If the basilar membrane vibrates with sufficient violence the hair 

 cells in the superstructure of the organ of Corti are stimulated; and 



^Proc. L R. E., July, 1931. 



* Read before the New York Academy of Medicine, Section of Otology, Nov. 1-1, 1930. 



