as to afford a candle-flame that may be introduced into the tube; light it, and introduce it about 5 or 6 inches, and a clear musical tone will be obtained.
During the experiments that were made in consequence of this view of the subject, many appearances occurred which might be added to the above account, to support the opinion that the vibration of the flame, in consequence of rapid successive explosions, is the cause of the sound; but they are neglected, because they are supposed unnecessary.
If the explanation given be true, then the only requisite to the production of these sounds is the successive sudden inflammation of portions of gaseous explosive mixtures. These mixtures are most easily made by propelling a stream of air on to a stream of inflammable gaseous matter; but it is also possible to make them in other ways, and the same phenomenon may be produced in a different manner.
That the tube is not essentially necessary, is shown by making it swell out into a cylinder of 3 or 4 inches diameter, except above and below; or part of it may be extended into a globe. I took two air-jars that were open above, but with contracted apertures; one of these was inverted over an inflamed jet of hydrogen, so as to form a lamp or bell-glass about it: there was no effect of sound, because the downward currents from above interfered with the stream of air issuing up from beneath, and made it irregular; but placing the second receiver on the first, applying them edge to edge, so as to preserve the current of air upwards from disturbing forces, the sounds were immediately produced; and lastly, I succeeded in obtaining the tones by the draught of a common chimney; for, by attaching a large inverted air-jar to the end of a funnel-pipe that came from the flue, closing the other lower opening into it, and introducing an inflamed jet of hydrogen within the lower contracted orifice of the glass, the sounds were produced.
That the same sounds may be obtained by means different to those above described, though depending on the same cause, is shown by some experiments made by Sir H. Davy, in his first researches on the miners' safety-lamp. Small wire-gauze safety-lamps being introduced into air-jars filled with explosive atmospheres, the gases burnt on the inside of the cylinder, and
