SOOT. 71 



A. Because they compel the air to 

 go through the fire, and not over it; 

 therefore the fire is well supplied with 

 oxygen, and the draught greatly 

 increased. 



Q. Why does a tin BLOWER INCREASE the 



DRAUGHT ? 



A. As all the air which enters the 

 chimney has to pass through the fire, it 

 is much hotter, and ascends the chimney 

 very fast; and the faster the air files up 

 the chimney, the faster it rushes towards 

 the fire also. 



Q. Why does a parlour often SMELL dis- 

 agreeably Of SOOT in SUMMER-TIME? 



A. The air in the chimney (being 

 colder than the air in the parlour) 

 descends into the room, and leaves a 

 disagreeable smell of soot behind. 



Q. Why are the CEILINGS of PUBLIC OFFICES 

 so BLACK andjilthy ? 



A. The heated air ascending, carries 

 the dust and fine soot to the ceiling; 

 where the hot air escapes through the 

 plaster, and leaves the soot and dust 

 behind. 



