1 1 4 Physiology. 



pushing toward the grate may be cold, and this has disad- 

 vantages that are hard to overcome in cold weather if there 

 is no other way of supplying heat. But it is a serious 

 question whether, with all our modern improvements in 

 heating, we have better air in our houses, or take cold less 

 often than our grandfathers, even if they did "roast on 

 one side while they froze on the other." 



Stoves as Heaters. A stove is a very much more effec- 

 tive heater than a grate. In the first place the stove gives 

 off heat on all sides. In the second place a good deal of 

 heat is given off by the stovepipe ; while in the grate 

 almost no heat is saved from the flame and smoke. 

 Again, the fire can be better regulated in the stove. 



Air Currents produced by Stoves. There is always a 

 current of heated air rising above a hot stove. Children 

 make whirligigs and other toys to place in these up-currents. 

 When this heated air reaches the ceiling it passes along 

 the ceiling, and comes down along the walls in the colder 

 parts of the room. At the same time colder air is flowing 

 along the floor toward the stove. This, in turn, is heated 

 and rises, making a constant circuit, along the floor to the 

 stove, up from the stove to the ceiling, along the ceiling 

 to the walls, and down the walls to its starting-point, again 

 to repeat the round. 



Stoves as Ventilators. If there is an opening at the 

 top of the room, heated air will escape through it. Often 

 the heat is used to warm upstairs rooms in this way. If 

 a window is open at the top, some heat is lost. To make 

 up for the losses above named, and also for the air that 

 enters the stove and goes up the chimney, more air is 

 drawn in usually around doors and windows. It is espe- 

 cially noticeable where there are openings near the floor. 



