DISCUSSION OF RESULTS 



Accuracy of Attenuation Coefficients 



The greater part of the data, especially the part which 

 showed large attenuation, was obtained at frequencies above 

 5. 1 kc/s, and the change in cavity loss is fairly small in 

 this range. The few points taken at frequencies lower than 

 5. 1 kc/s were obtained for the cold oceanic water, and 

 these samples had a very low attenuation. 



The values of the attenuation rate indicated in the cali- 

 bration curve of figure 10 were computed from the relation 



_ 36. 5 _„_ „ 

 a — db/kyd 



The reverberation time t was obtained from recordings 

 like those shown in figures 5 to 7 by matching a straight 

 black hairline, engraved in a piece of clear plastic, with 

 the reverberation curve. By having the curves read several 

 times by different observers, it was found that the accuracy 

 with which the reverberation time could be read was: 



At = ± 0. 02 sec for t = 1 sec or a = 36. 5 db/kyd 



and 



At = ± 0. 05 sec for t = 3 sec or a = 12 db/kyd 



The relationship between At and Aa can be obtained by 

 differentiation of the above relation for a . This yields 



M At 

 Aa o = + ~ J^ 



73 



