ARTICLES BY BELL SYSTEM AUTHORS 209 



Abstract — In many acoustically coupled systems the methods of geo- 

 metrical acoustics do not apply. Reverberation formulas as ordinarily used 

 would lead to incorrect results. This paper approaches the problem of 

 coupled rooms from the 'Vave" point of view, treating the coupled rooms 

 as a boundary value problem in obtaining an approximate solution. The 

 results explain some discrepancies noted by earlier researchers between 

 experiment and predictions from geometrical acoustics; for example, the 

 dependence of absorption in a room on the position of the open area which 

 couples the room to an adjacent one. For the case where the window area 

 which couples one room to another is comparable in size with the partition 

 which separates the rooms, the effect of the partition will be least when it 

 is at a particle- velocity node. For the case where the window area is small 

 compared with the partition which separates the two rooms, the effect of 

 the coupling window depends on the square of the unperturbed pressure at 

 the window. Thus the effect of the window varies with position and is least 

 at a pressure node. Experimental data on isolated modes of vibration of a 

 coupled system are given which check the results predicted by this applica- 

 tion of the wave theory. 



Quantitative Spectrochemical Analysis of Ashes, Deposits, Liquids, and 

 Miscellaneous Samples."^ E. K. Jaycox.^ References. Anal. Chem., v. 22, 

 pp. 1115-1118, Sept. 1950. 



Abstract — A general technique is described which is appHcable to the 

 quantitative spectrochemical analysis of a wide variety of materials. Sample 

 preparation, the incorporation of spectrochemical buffers, and excitation 

 procedures are discussed for typical cases which illustrate the scope and 

 possibilities of the method. Examples include the analysis of the ashes of 

 rubber, plastics, paper, and cloth; deposits on walls of vacuum tubes and 

 other surfaces; water, oils, and other liquids; and miscellaneous solid ma- 

 terials. 



Response Peaks in Finite Horns* C. T. Molloy.^ Acoustical Soc. Am., Jl., 

 V. 22, pp. 551-557, Sept. 1950. 



Abstract — It is the purpose of this paper to discuss the theory of the 

 axial response curves of the class of acoustical systems comprising a driv- 

 ing unit and a finite "Hyperbolic Horn". The term "Hyperbolic Horn" 

 as used in this paper denotes horns of the type first discussed by Salmon. 

 It is proposed to derive an expression from which the response curve may be 

 calculated. A method will also be given by means of which the peaks in this 

 response curve may be located without the necessity of computing the 

 whole curve. Finally the converse problem will be discussed, namely, how to 



* A reprint of this article may be obtained on request to the editor of the B.S.T.J. 

 1 B.T.L. 



