COMBUSTION. 



133 



Fig. 50. 



a little piece of this metal may be thrown into the bell-jar 

 to show that water has formed on its sides. In the flame 

 of burning coal gas we have both the unions mentioned in 

 169, producing water and carbonic anhydride. The coal 

 gas consists of a mixture of several hydrocarbons, or bod- 

 ies consisting of hydrogen and carbon chemically combined. 

 Both of these in burning unite with the oxygen of the air. 

 In doing this, however, the carbon and hydrogen become 

 separated from each other. The hydrogen, being more com- 

 bustible than the carbon that is, more ready to unite with 

 oxygen burns first, and the little separated particles of 

 carbon burn in the flame of the hydrogen, giving to it its 

 brightness. The little bright flashes that you see continu- 

 ally shooting up in a gas-light are occasioned by the burn- 

 ing of these minute particles of carbon. 



171. Chemistry of a Candle. The same thing substan- 

 tially occurs in the combustion of a common candle. The 

 flame here is burning gas, and consists of nearly the same 

 gases as those which issue from a gas-burner. The tallow 

 is composed of carbon and hydrogen. The process, or rath- 

 er series of processes, by which this solid compound is con- 



