142 INCANDESCENCE. 



crease the rapidity of the combustion, so as to increase the 

 heat and raise the solid particles to a higher degree of in- 

 candescence. And to increase the combustion, the proper 

 means is to increase the supply of oxygen. The most ob- 

 vious way of doing this is to facilitate the access of air, 

 since air aifords the most abundant natural supply of oxy- 

 gen that we have at command. 



It was this idea which Argand carried into practical ef- 

 fect in his celebrated burner, by which he supplied a cur- 

 rent of air on the inside as well as the outside of the flame, 

 and also at the same time increased the rapidity of the sup- 

 ply by creating a draft by means of a transparent chimney, 

 as has already been fully explained. 



The same effect in principle is produced in a common 

 form of burner for gas, called the " bat's wing." This con- 



TJIE BAT'S wi 



sists in so forming the opening for the issue of the gas as 

 to throw the flame into a broad, flat form, so as to give the 

 air access to a very enlarged surface of it. 



This method, like that of Argand, as well as a great 



