362 A. M. Mayer—Researches in Acoustics. 
Art. XXXIL—Researches in Acoustics ; by ALFRED M. MAYER. 
Paper No. 7, containing : 
Experiments on the Reflection of Sound from Flames and Heated 
Gases. 
THE reading of the recent interesting research of Prof. Tyn- 
dall on “Experimental Demonstrations of the Stoppae of 
Sound by partial Reflections ina non-homogeneous Atmosphere” 
(Proc. R. S., Jan., 1874; Nature, Jan. 29, Feb. 5), and of the 
subsequent paper by Mr. Cottrell “On the Division of a Sound- 
wave by a Layer of Flame or Heated Gas into a reflected and a 
transmitted Wave” (Proc. R. S., Feb. 12, 1874), caused me to 
turn my attention to the experimental illustration of the reflec- 
tion of sonorous vibrations from flames, heated gases, and from 
sheets of cold gases and vapors. 
(See the figure.)* By trial = 
the two planes of the fork are = 
placed at such distances from ete : 
the resonators that complete interference of the vibrations 
* The wood-cut illustrating this paper has been kindly given to me by Dr. 
Henry Wurtz, the editor of the American Gas-Light Journal, in which publication 
an account of these experiments first appeared—May 2, 1874. 
