66 



PROCEEDINGS OF THE AMERICAN ACADEMY, 



were nine observers stationed at different points in the room. These 

 observers, whose kindness and skill it is a pleasure to acknowledge, 



Ci Ca 



Cs C4 



Figure 2. 



C, 



c. 



c, 



The absorbing power of .an audience for different notes. The lower curve 

 represents the absorbing power of an audience per person. Tlie upper curve rep- 

 resents the absorbing power of an audience per square meter as ordinarily seated. 

 Tlie vertical ordinates are expressed in terms of total absorption by a square 

 meter of surface. For the upper curve the ordinates are tlius the ordinary coeffi- 

 cients of absorption. The several notes are at octave intervals as follows, C^ 64, 

 C2 128, C3 (middle C) 256, C4 512, C5 1024, Cg 2048, C7 4096. 



had prepared themselves by previous practice for this one experiment 

 As in the work of six years ago, the writer's key controlled the organ 



