172 A. M. Mayer—Researches in Acoustics. 
(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, 
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 ead le 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 origi 
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 wit 
its own tone. I have thus been able, by placing one fork after 
another, of the series of the harmonics of the Ut, reed, to show 
the composition of its sound to a large audience with entire 
satisfaction. I have also succeeded with : 
ment. Forcibly sound the reed, and place around the opening 
Th to suc 
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 harmonies 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 anal- 
yzed. en knowing the number of beats that the fundamen- 
tal of the note gives with its corresponding fork, we can desig- 
nate the number of any other harmonic by the number of beats 
it makes with a fork of known pitch; for the number of beats 
observed, when referred to the number of beats of the funda- 
mental as unity, will be directly as the number of the harmoni¢ 
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