Abstracts of Bell System Technical Papers 

 Not Appearing in this Journal 



New Methods and Apparatus for Testing the Acuity of Hearing. 

 Harvey Fletcher. ^ This paper presented before the American 

 Otological Society, classifies hearing tests in four groups according to 

 their purpose. 



1. Industrial or those made for determining the fitness of a candi- 

 date for employment. In certain types of work it is particularly 

 important that a prospective employee meet a definite requirement 

 for acuity of hearing. Tests made in the army and na\y tor \arious 

 branches of service are conspicuous examples of this kind of test. 



2. Educational or those made for determining the degree of hearing 

 of school children both in the public schools and in the schools for the 

 deaf for the special purpose of determining the proper methods to be 

 used in their education. 



3. Clinical or those made for assisting the physician to make a proper 

 diagnosis of the cause of deafness. 



4. Research or those made to determine new facts about both 

 normal and abnormal hearing. 



It is highly desirable that a single scale be used for representing 

 the degree of hearing which is independent of the method used and 

 which has a general application to the four purposes enumerated. 

 Such a scale is proposed and it is shown how the commonly made 

 voice test, watch tick, acoumeter, coin click and tuning fork tests 

 can be expressed in terms of hearing loss units on this scale. 



The paper is concluded by summarizing the dift'erent methods for 

 testing the acuity of hearing which are as follows: (1) voice tests, 

 (2) phonograph audiometer, (3) hearing loss for speech calculated 

 from audiogram, which audiogram may be obtained in three ways, 

 (a) tuning forks (constant initial amplitude), (b) tuning forks (com- 

 parison with hearing of tester), (c) pitch range audiometer. 



The Relation Between the Loudness of a Sound and Its Physical 

 Stimulus. J. C. Steinberc..- Experiments with main- types of 

 sounds have shown that the loudness of a sound is a function of its 



1 The Laryngoscope, Vol. XXXV, \o. 7, July, 1925. 



2 Pliysical Review, Vol. 26, pp. 507-523, Oct., 1925. 



214 



