EXPANSION. 1 1 1 



the same as a stone falls faster and faster 

 the nearer it approaches to the ground. 



Q. Why will a LONG chimney SMOKE, unless 

 the FIRE be pretty FIEECE ? 



A. If the fire be not pretty fierce, its 

 heat will not be sufficient to rarefy all the 

 air in the chimney ; and then the chimney 

 will smoke. 



Q. WHY will the chimney smoke, if the fire be 

 not BIG enough to heat ALL tlie air in the CHIMNEY 

 FLUE? 



A. Because the cold air (condensed 



in the upper part of the flue), will sink 



from its own weight, and sweep the 



ascending smoke back with it into the 



room. 



Q. What is the use of a COWL upon' a chimney- 

 pot? 



A. The cowl acts as a screen against 

 the wind y to prevent it from blowing into 

 the chimney. 



Q. What HARM would the WIND do, if it were 

 to BLOW into a CHIMNEY? 



A. 1st It would prevent the smoke 

 from getting out : and 



2ndly The cold air (introduced into 



L 2 



