22 On the Sounds produced by Flame in Tubes. [1818. 



in a different manner, an^.1 may result from the action of any 

 flame. 



I was induced to make a few experiments on this subject, in 

 consequence of the request of Mr. J. Stodart that it should 

 be introduced at one of the .evening meetings of the Members 

 and friends of the Royal Institution ; and was soon satisfied 

 that no correct explanation had been given. That the sounds 

 were not owing to any action of aqueous vapour, was shown 

 by heating the whole tube above 212; and still more evidently 

 by an experiment, in which I succeeded in producing them 

 from a jet of carbonic oxide. That they do not originate in 

 vibrations of the tube, caused by the current of air passing 

 through it, was shown by using cracked glass tubes, tubes 

 wrapped up in a cloth ; and I have obtained very fine sounds 

 by using a tube formed at the moment by rolling up half a 

 sheet of cartridge-paper, and keeping it in form by grasping it 

 in the hand. The sounds have been accounted for, as well as 

 their supposed peculiarity of production by hydrogen, by the 

 supposition of a rapid current of air through the tube ; but 

 that this is not essential, is shown by using tubes closed at one 

 end, and bell-glasses, as described by Mr. Higgins in his first 

 experiment. 



I was surprised to find, on my first trials with other gases, 

 that I could produce those sounds from them which had been 

 supposed to be generated exclusively by hydrogen ; and this, 

 with the insufficiency of the explanations that had yet been 

 given, induced me to search after the cause of an effect which 

 appeared to be produced generally by all flame. 



In examining attentively the appearance of a flame when 

 introduced into a tube, it will commonly be found, that, on 

 coming within its aperture, a current of air is established 

 through the tube, which compresses the flame into a much 

 smaller space ; it is slightly lengthened, but its diameter is 

 considerably diminished : on being introduced a little further, 

 and as the tube becomes warm, this effect is increased, and the 

 flame is gradually compressed a little above its commencement 

 at the orifice of the jet, more than at any other part ; a very 

 faint sound begins to be heard, and as it increases, vibrations 

 may be perceived in the flame, which are most evident in the 

 upper part, but frequently also perceptible in the lower and 



