CONVECTION 



103 



0.07203+0.001265-6(0.000059) =0.072941, weight of 1 cubic 

 foot of air 65 F., 60 per cent relative humidity, barometric pressure 

 30. 



0.072941 times 3000 cubic feet = 218.8 pounds, weight of the 

 air in the room. 



To change pounds to grains multiply by 7000. 







Heating of a Room with a Radiator. The heat is brought to the 

 inside of the radiator by convection from the furnace in the base- 

 ment. Some of the heat escapes into the room by radiation, as has 

 already been mentioned, but the greater part of the room is heated 

 by convection. The heat passes from the inside of the radiator to 

 the outside by conduction. The air, coming in contact with the 

 radiators, in turn becomes heated, also by conduction. This heated 

 air rises, being pushed up by the cold air rushing in toward the radia- 

 tor. The air at the ceiling cools slightly and sinks, coming in con- 

 tact with the objects of the room and giving up heat. 



