50 CHEMICAL ACTION. 



been heated by the fire) the more rapid 

 will be the current of air towards 

 that fire. 



Q,. Wliy does rarefied air afford LESS NOU- 

 RISHMENT to fire, than cold air ? 



A. Because it is spread out, (like a 

 piece of gold beaten into leaf} ; and 

 as a square inch of gold leaf will not 

 contain so much gold as a square inch 

 of bullion so, a square inch of rarefied 

 air has less body, than a square inch 

 of cold air. 



Q. Why does a FIBE burn more fiercely in 

 the OPEN AIR? 



A. 1st Because the air out-of-doors 

 is more dense, than the air in-doors : and 



2ndly Because air is more freely 

 supplied to a fire out-of-doors. 



Q. Why is the air out-of-doors more DENSE 

 than that in-doors? 



A. Because the circulation is more 

 free; and as soon as any portion has 

 been rarefied, it instantly escapes, and is 

 supplied by colder currents. 



Q. Why does not a FIRE burn so freely in a 

 THAW, as in a FROST? 



