Prof. A. M. Mayer's Researches in Acoustics, 515 



shall hear them singing out clearly above the general chorus of 

 the other harmonics. Thus I have often successfully shown to an 

 audience the composition of a composite sound. 



(4) Analysis by means of Resonant boxes carrying solid bodies, 



tuned in unison with the sounds to which the air in these boxes 



resounds. 



This method is an excellent one when the composite sound 

 can be obtained with intensity, when the boxes are accurately in 

 tune with the solid bodies (forks or strings) attached to them, 

 and when the boxes are in unison with the sonorous elements of 

 the composite sound which we would analyze. The last-men- 

 tioned condition is not always fulfilled in the boxes on which 

 forks have been some time mounted ; for the former are apt to 

 change their interior capacity by warping. This fact can 

 readily be ascertained by partly introducing the hand into the 

 mouth of the box and noting the effect on the intensity of the 

 sound. 



This method of analysis is similar to the one previously de- 

 scribed; for the resonant box of a fork acts like a resonator, 

 and can be used to intensify any harmonic of a composite sound,. 

 But there is an important difference in the methods ;. for the fork 

 or the string, being in unison with the proper note of the mass of 

 air in the box, is set in vibration by the latter ; so that, after the 

 box has been removed from the vicinity of the origin of the 

 composite sound and the latter has ceased, we find that the 

 fork sings out alone, and thus shows that it has selected from 

 a chorus of harmonics that one which is in unison with its 

 own tone. I have thus been able, by placing one fork after 

 another of the series of the harmonics of the Ut 2 reed, to show 

 the composition of its sound to a large audience with entire 

 satisfaction. I have also succeeded with the following experi- 

 ment. Forcibly sound the reed, and place around the opening 

 of its "stump" all the eight forks of the harmonic series 

 of Ut 2 , with the mouths of their resonant boxes toward the 

 reed. After the reed has sounded for a few seconds, stop it; 

 and we shall find that all the forks are in vibration, and thus 

 singing together they approximately reproduce the sound of the 

 reed. This experiment, to succeed, requires the resonant boxes, 

 the forks, and the harmonics of the reed to be in exquisite 

 unison. 



(5) Analysis by means of the beating of simple sounds of known 

 pitch with the harmonics of the composite sound to be analyzed. 

 If we use forks for the simple sounds, it will be better slightly 



to flatten or sharpen the note of the sound to be analyzed. 



2 L2 



