A. M. Mayer— Researches in Acoustics. 178 
in the series. If we cannot well alter the pitch of the compo- 
on graduated prongs, or loaded strings accurately tuned and 
cale 
2 
. 
gently vibrated and resonators used to assist the ear. 
(6.) Analysis by means of a loose membrane which receives the 
composite sonorous wave and transmits its vibrations through 
Jjilaments or light rods to a series of forks mounted on their 
resonant cases, 
This method of analysis is the one we devised in our experi- 
mental confirmation of Fourier’s theorem and described in sec. 
the aerial vibrations produced by the reed. _ ; 
_ An experiment like the above is instructive as an analogical 
illustration of the manner in which we may imagine an etherial 
Vibration to produce chemical decomposition by causing such 
powerful synchronous vibrations in the molecules of compounds 
as to shake their atoms asunder; and we have already seen. 
how very feeble impulses sent through a medium of great ten- 
uity can, when rapidly recurring and of the proper period, pro- 
duce mechanical effects which at first sight appear incredible. 
Time is required in both cases to produce an appreciable action. 
The time required in the case of the sonorous vibrations de- 
