METHODS OF HEATING BUILDINGS 



21 



Methods of heating buildings. Open fireplaces and stoves. 

 If heat did not cause expansion and change in temperature, it 

 would be impossible to heat our houses and to protect ourselves 

 against the biting blasts of winter. The burning coal warms 

 and expands the air within the furnace, causing it to rise through 

 the stovepipes and thus to carry heat to the different parts of 

 the house. Open fireplaces, old-fashioned stoves, and new- 

 fashioned furnaces owe their existence to these two effects of 

 heat. In olden times, man heated his modest dwelling by open 

 fires alone. The burning logs gave warmth to the cabin and 

 served as a primitive cooking agent ; and the smoke which 

 usually accompanies burning was carried away through the 

 chimney. But in an open 

 fireplace much heat escapes 

 with the smoke and only a 

 small portion streams into 

 the room and gives warmth. 



When fuel is placed in an 

 open fireplace (Fig. n) and 

 lighted, the air immediately 

 surrounding the fire becomes 

 warmer and, because of ex- 

 pansion, becomes lighter than 

 the cold air above. The cold 

 air, being heavier, falls and 

 forces the warmer air upward, 

 and with the warm air goes 

 the disagreeable smoke. The 

 fall of the colder and heavier 

 air, and the rise of the warmer and hence lighter air, is similar 

 to the exchange which takes place when water is poured upon 

 oil; water, being heavier than oil, sinks to the bottom and 

 forces the oil to the surface. 



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FIG. ii. The open fireplace as an early 

 method of heating. 



