268 



THE SPECIAL SENSES 



Gas chamber 

 Air chamber 

 Vibrating membrane 



Revolving mirror 



FIG. 147. Apparatus for analyzing sound by means of manometric flame,. 



Image in mirror 

 No sound 



Image produced,, 



by tuning-fork, 



pitch low C, 



By tuning-fork, y 

 middle C. 



By above forks , 

 .in unison. // 



By singing 

 vowel E, pitch' 

 middle C 



vowel o 

 middle C. 



IG. 148. Analysis by means of manometric flames, of the vibrations producing 

 certain sounds. 



