chap, xxxiii.] ANALYSIS OF SOUND, 



447 



led thither from an ordinary gas-pipe, and from this 

 side of the chamber is a little burner similar to that 

 already described (Fig. 193). Each resonator is con- 

 nected in this way with its own gas chamber and 

 burner, and the bur- 

 ners are all placed in 

 a row one above 

 another, as shown in 

 Fig. 194. Now if the 

 air in any one resona- 

 tor be agitated, the 

 indiarubber partiti o 11 

 of the chamber, 

 separating gas on one 

 side from air continu- 

 ous with the resonator 

 on the other, will be 



thrown into vibration, Fig 194 ._ Analysis of Sound by 

 the gas and the flame Koenig's Apparatus. 



will both be agitated. 



The agitation of the flame will be perceptible to the 

 naked eye by its becoming thinner and bluer. By a de- 

 vice due to Wheatstone, this may be rendered more 

 striking. Opposite the eight gas burners is a long mirror 

 with four reflecting sides, at right angles to one another. 

 This may be revolved on an almost perpendicular axis, 

 by a toothed wheel arrangement. If the gas issuing 

 from the burners be lighted, and the mirror revolved, 

 the light reflected from the four surfaces of the mirror 

 gives the impression of a continuous band. If the 

 flame be agitated the revolutions of the mirror separate 

 out each movement, and the band of flame is now 

 segmented (Fig. 194, a b). There are, then, eight 

 flames, one corresponding to each resonator ; in the 

 revolving mirror are seen eight bands of flame. If 

 any one flame be agitated it is at once detected by 

 the segmentation, as seen in the mirror ; so that if 



