FIRE. 39 



coals are put on, their under surface is 

 heated before the upper surface ; and one 

 is red (or in a state of combustion), while 

 the other is black. 



Q. Which burns the quicker, a BLAZING fire, 

 or a RED HOT one? 



A. A Hazing fire burns out the fuel 

 quickest. 



Q. Why do BLAZING COALS BURN QUICKER 

 than red hot ones ? 



A. In red hot coals, only the mere 

 surface is in a state of combustion, because 

 the carbon is solid; but in a blazing fire, 

 (where the gases are escaping), the whole 

 volume of the coal throughout is in a 

 state of decomposition. 



Q. What is SMOKE ? 



A. Unconsumed parts of fuel 

 (principally carbon), separated from the 

 solid mass, and carried up the chimney by 

 the current of hot air. 



Q. Why is there MORE SMOKE when COALS 

 are FRESH added, than when they are red hot ? 



A. Carbon (being solid), requires a 

 great degree of heat to make it unite with 

 oxygen, (or, in other words, to bring it 



E 2 



