IQ2 



HEATING OUR HOMES 



of the heat obtained from the fuel. Air coming in contact 

 with the hot surface of the stove expands and becomes 

 lighter, and is pushed up by heavier air, which comes in to 

 take its place (see arrows in diagram). These warm cur- 

 rents of air become cool as they pass by the windows and 

 cold walls and other surfaces which absorb heat, and sink 



again to the floor. 

 Since the stove is 

 warmer than other 

 objects in the room, 

 it radiates heat to 

 them; heat is 

 brought also through 

 the metal from the 

 inside to the outside 

 surface by conduc- 

 tion. Thus all three 

 methods of heat 

 transference are used 

 to some extent in 

 heating a room. 



The hot-air fur- 

 nace. The hot-air 

 furnace has come 

 into general use and 

 is much liked because it does the work of several stoves 

 and requires no more attention than one. The furnace is 

 simply a large central stove placed in the cellar, and cov- 

 ered with a metal jacket, from the top of which metal 

 tubes, or ducts, lead out to the different rooms to be 

 heated. Air from out of doors is brought to the bottom 

 of the space between the fire box and the inclosing jacket, 



A hot-air furnace. 



