THE BUDE AND OXYHYDROGEN LIGHTS. 159 



by heat consists of particles of carbon, heated by the com- 

 bustion chiefly of hydrogen from the oil, and increased in 

 intensity by currents of air both on the inside and outside 

 of the flame. 



" 2. THE BUDE LIGHT is the same, except that, instead 

 of currents of air, currents of pure oxygen are made to flow 

 in contact with the flame. Air contains only about one 

 fifth of its bulk of oxygen ; the rest is nitrogen, which, for 

 the purposes of combustion, is only in the way. The ra- 

 pidity and intensity of the combustion is greatly increased 

 by supplying pure oxygen to the fire. In the burning of 

 magnesium, it is found, by careful comparison, that the in- 

 tensity of the light is doubled when it is supplied with 

 pure oxygen. In the same way, the light in the Argand 

 burner is vastly increased when pure oxygen is supplied 

 to it instead of common air. 



" The Bude light has been used a great deal, sometimes 

 for light-houses, and sometimes for other purposes; but 

 there was found to be this inconvenience about it, that it 

 required the apparatus for producing the oxygen always 

 at hand ; and the process required a good deal of atten- 

 tion, and involved some increased expense. 



" 3. THE OXYHYDROGEN LIGHT. In the case of the Ar- 

 gand and Bude lights, the solid substance rendered incan- 

 descent is composed of particles of carbon, which are fur- 

 nished, together with the hydrogen for producing the heat, 

 by the oil or other hydrocarbon that is burned. But in 

 the oxyhydrogen light, the hydrogen, as well as the oxy- 

 gen, is furnished pure, and the heat which is produced by 

 their combustion is directed against the point of a cone 

 formed of lime, or some other substance capable of sustain- 

 ing such a heat without melting or burning, and this lime 

 is the solid substance which becomes incandescent and 

 emits the light." 



