in a different manner, and 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 beating 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 from 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
