Page:Experimental researches in chemistry and.djvu/41

26 produced sounds similar to those obtained from a jet of Home in a tube.

Having thus endeavoured to account for the phenomenon of sounds produced by jets of flame, in tubes and other vessels, I shall notice shortly the combustible bodies I have tried. Carbonic oxide, olefiant gas, light hydro carbonate, coal-gas, sulphuretted hydrogen, and arseniuretted hydrogen, were burned at the end of a long narrow brass tube rising up from a transferring jar placed under pressure in a pneumatic trough. Æther was burned from the end of a tube fixed in a flask containing a small quantity which was heated; but a better method, and one I afterwards adopted, is to pour a little:ether into a bladder, and then force common air in; so much:ether rises in vapour as to prevent the mixture being detonating, and it may be pressed out and burnt at the end of a tube. All these were very successful. Alcohol was more difficult to manage from being less volatile; but it succeeded when raised in vapour from a flask and burnt at a tube. In trials made with a wax taper, no distinct tone could be produced; but when the tube was made very hot, so as to assist the current through it, something like the commencement of a sound was heard at the moment the taper was blown out by the current.

Hydrogen is by far the best substance by which to produce these tones; and its superiority depends upon the low temperature at which it inflames, the intense heat it produces in combustion, and the small quantity of oxygen that a given bulk of it requires. It is in consequence less easily extinguished by the current than other gases, the current formed is more powerful and rapid, and an explosive mixture is sooner made. With gases producing little heat by combustion, and therefore occasioning but a feeble current, the effect is increased by first heating the tube at a lire, and when not heated previously, the tone is perceived to improve as the tube becomes hot from the flame playing in it.

Some variations of the form of the vessel enclosing the flame, and the material used, have been mentioned. Globes from 7 to 2 inches in diameter, with short necks, give very low tones: bottles, Florence flasks, and phials have always succeeded: air-jars from 4 inches diameter to a very small size