: 
A. M. Mayer—Researches in Acousties. 247 
can go from the law connecting the pitch of a sound with the 
duration of its residual sonorous sensation to the law giving the 
numbers of beats throughout the musical scale which produce 
the most dissonant sensations. 
3. Application of the above laws in a new method of Sonorous 
Analysis, by means of a perforated rotating disc. 
It is an interesting deduction from the laws we have established 
that a composite sound can be analyzed by means of a rotatin 
dise with sectors cut out of it. Thus, on rotating a large perfo- 
rated disc with great velocity before a reed pipe, and placing the 
ear close to the disc,—or in connection with the gutta-percha 
funnel, by means of the rubber tube,—we shall have the com- 
posite sound reaching the ear in a series of impacts which suc- 
ceed each other so rapidly that even those of the highest har- 
monic of the reed blend into a continuous sensation; but, on 
velocity brings out the beats of the next lower harmonic, and 
so on, until the velocity has been so diminished that even the 
beats of the lowest, or fundamental, harmonic are perceived ; 
and then all of the component sounds of the reed are beating 
in unison ; but yet the effects they produce on the ear are ver, 
different, for the higher harmonics, notwithstanding their feebler 
intensities, must be heard more distinctly, because their inter- 
mittences are furthest removed from the numbers that cause 
their sensations to blend. In other words, the highest harmon- 
ies, in the phase of the experiment above described, app 
them to give their greatest dissonant effects. 
sonorous analysis was arrived at as a deduction from our laws, 
w 
for all colors, but the excitation takes See sooner for the red 
and the violet than for the green. “Silon fait tourner ce 
semblable disque, lentement d’abord, puis, graduellement, de 
