74 CHEMICAL ACTION. 



CHAPTER V. 

 LAMPS AND CANDLES. 



Q,. Of what are OIL, TALLOW, and WAX 

 composed ? 



A. Principally of carbon and hydro- 

 gen gas. The solid part is carbon, the 

 volatile part is gas. 



Q, What is CARBON? 



A. A solid substance, generally of a 

 black colour; well known under the 

 forms of charcoal, lamp-black, coke, 

 black-lead, &c. 



Q. What is HYDROGEN GAS ? 



A. The principal ingredient of 

 water. It is well known in the form of 

 common coal gas : it burns so readily 

 that it used to be called "inflammable 

 air."* 



Q. Why does a CANDLE BUBN when lighted ? 



A. The heat of the lighted wick 



decomposes the tallow into its elementary 



* To make hydrogen gas, see p. 34. 



