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A. M. Mayer— Researches in Acoustics. 365 
sity of the sonorous vibrations, which have traversed the flame, 
when it is taken off, the aerial vibrations produced by the fork 
are far more intense in the latter circumstances than in the for- 
mer. By a method described by me in this Journal, Feb., 
1871, I measured the relative intensities of the aerial vibrations 
in these two conditions of vibration. The sheet of caoutchouc 
was enclosed in a compound thermo-battery and the fork 
vibrated during a known interval; the rubber was heated by 
the vibrations which would have appeared as sonorous vibra- 
tions if the rubber had been removed from the fork. The 
ront of its resonator, equalled 
