1818.] On the Sounds produced by Flame in Tubes. 23 



smaller portion ; these increase with the sound, which at last 

 becomes very loud, and if the flame be further introduced into 

 the tube, it is generally blown out. Such are the general 

 appearances with hydrogen. If a jet of olefiant or coal-gas, 

 both of which I have ascertained may be used successfully, 

 be substituted, then, in addition to those appearances, it will 

 be perceived, that as the bright flame of the gas enters the 

 tube, its splendour is diminished, and it burns with less light. 



By substituting other gases and inflammable vapours for 

 hydrogen, and using other vessels than tubes, I was enabled 

 so to magnify the effects, as to perceive more distinctly what 

 took place in the flame at these times, and soon concluded 

 that the sound was nothing more than the report of a con- 

 tinued explosion. 



Sir H. Davy has explained the nature of flame perfectly; 

 and has shown that it is always a combination of the elements 

 of explosive atmospheres. In continued flame, as of a jet of 

 gas, the combination takes place successively, and without 

 noise, as the explosive mixture is made. In what is properly 

 called an explosion, the combination takes place at once 

 throughout a considerable quantity of mixture, and sound 

 results from the mechanical forces thus suddenly brought into 

 action ; and a roaring flame presents some of the characters of 

 both. If a strong flame be blown on by the mouth, a pair of 

 bellows, the draught of a chimney, or other means, the air and 

 the gaseous inflammable matter are made to mix in explosive 

 proportions in considerable quantities at once, and these being 

 fired by the contiguous flame, combine at once throughout 

 their whole extent, and produce sound : the effect is rapidly 

 repeated in various parts of the flame as long as the air is mixed 

 thus forcibly with it, and a repetition of noise is produced, 

 which constitutes the roar. 



Now this I believe to be exactly analogous to that which 

 takes place in what have been called the singing tubes ; but 

 in them the explosions are generally more minute and more 

 rapid. By placing the flame in the tube, a strong current of 

 air is determined up it, which envelopes the flame on every 

 side. The current is stronger in the axis of the tube than in 

 any other part, in consequence of the friction at the sides and 

 the position of the flame in the middle; and just at the en- 



