236 Intelligmce and Miscellaneom Articles. 



unless the discharge of gas was so regulated that the flame approxi- 

 mated the condition of flaring. I likewise determined hy experi- 

 ment, that the effects ioere not produced by jarring or shaking the 

 floor and walls of the room by means of repeated concussions. 

 Hence it is obvious that the pulsations of the flame ivere not owing 

 to indirect vibrations propagated through the medium of the walls 

 of tlie room to the burning apparatus, but must have been produced 

 by the direct influence of the aerial sonorous pulses on the burning jet. 



In the experiments of M. Schaffgotsch and Prof. J. Tyndall, it is 

 evident that "the shaking of the singing flame within the glass tube," 

 produced by the voice or the syrene, was a phtenomenon perfectly 

 analogous to what took place under my observation without the inter- 

 vention of a tube. In my case, the discharge of gas was so regulated 

 that there was a tendency in the flame to flare, or to emit a "singing 

 sound." Under these circumstances, strong aerial pulsations occur- 

 ring at regular intervals were sufficient to develope synchronous 

 fluctuations in the height of the flame. It is probable that the 

 effects would be more striking when the tones of the musical instru- 

 ment are nearly in unison with the sounds which would be produced 

 by the flame under the slight increase in the rapidity of discharge of 

 gas required to manifest the phenomenon of flaring. This point 

 might be submitted to an experimental test. 



As in Prof. Tyndall's experiments on the jet of gas burning within 

 a tube, clapping of the hands, shouting, &c. were ineffectual in con- 

 verting the " silent" into the " singing flame," so in the case under 

 consideration, irregular sounds did not produce any perceptible in- 

 fluence. It seems to be necessary that the impulses should accumu- 

 late in order to exercise an appreciable effect. 



With regard to the mode in which the sounds are produced by the 

 combustion of gases in tubes, it is universally admitted that the ex- 

 planation given by Prof. Faraday in 1818 is essentiLdly correct. It 

 is well known that he referred these sounds to the successive explo- 

 sions produced by the periodic combination of the atmospheric oxygen 

 with the issuing jet of gas. While reading Prof. J. Plateau's admi- 

 rable researches (third series) on the " Theory of the modifications 

 experienced by Jets of Liquid issuing from circular orifices when 

 exposed to the influence of Vibratory Motions*," the idea flashed 

 across my mind that the phfenomenon which had fallen under my 

 observation was nothing more than a particular case of the effects of 

 sounds on all kinds of fluid jets. Subsequent reflection has only 

 served to fortify this first impression. 



The beautiful investigations of Felix Savart on the influence of 

 sounds on jets of water, afford results presenting so many points of 

 analogy with their effects on the jet of burning gas, that it may be 

 well to inquire whether both of them may be referred to a common 

 cause. In order to place this in a striking light, I shall subjoin some 

 of the results of Savart's experiments. Vertically descending jets of 

 water receive the following modifications under the influence of 

 vibrations : — 



* Phil. Mag. S, 4. vol. xiv. p. 1 et seq., July 1857. 



