40 CHEMICAL ACTION. 



into a state of perfect combustion) : when 

 coals are fresh laid on, more carbon is 

 separated than can be reduced to com- 

 bustion ; and so it flies off in smoke. 



Q. Why is there so LITTLE SMOKE with a RED 

 HOT FIRE ? 



A. When a fire is red hot, the entire 

 surface of the coals is in a state of 

 combustion; so a very little flies off 

 unconsumed, as smoke. 



Q. Why are there DARK and BRIGHT SPOTS 

 in a CLEAR cinder FIRE ? 



A. Because the intensity of the 

 combustion is greater in some parts of 

 the fire, than it is in others. 



Q. Why is the intensity of the combustion so 

 unequal ? 



A. Because the air flies to the fire in 

 various and unequal currents. 



Q. Why do we see all sorts of GROTESQUE 

 FIGURES in hot COALS ? 



A. Because the intensity of combus- 

 tion is so unequal, (owing to the gusty 

 manner in which the air flies to the fuel) ; 

 and the various shades of red, yellow, and 

 white heat) mingling with the black of the 



