Luminosity of Gases. 



128 



Chemistry of Flame" (Smithells and Ingle, Jonrn. Chem. 

 Soc. lxi. p. 204, 1892), from which it is clear that the flame 

 of a Bunsen-burner must be regarded as consisting of two 

 distinct cones of combustion. In the inner one a partial 

 combustion of gas takes place at the expense of the oxygen ot 

 the air admitted through the air-valves : in the outer cone, 

 such of these products of partial combustion (chiefly carbon 

 monoxide and hydrogen) as are capable of further oxidation are 

 burnt in the external air ; but, being mixed with a large 

 quantity of fully oxidized products and with all the nitrogen 

 passing through the inner cone, the flame produced is of a 

 much Tower average temperature than that of the inner cone. 

 The apparatus used in the experiments to which allusion 

 has just been made secures a wide separation of the cones 



.-& 



of the flame of a Bunsen-burner, and so affords a simple 

 means of ascertaining the different spectral effects obtainable 

 in different parts of the flame, 



