CHAPTER II 

 VENTILATING THE HOME 



1. What are the essentials for a good system of 

 ventilation ? 



2. From the standpoint of the ventilation pro- 

 vided which is the best heating system ? 



By ventilation is meant the keeping of the air in which we 

 live in such a condition that it will be healthful to our bodies. 

 The problems of heating and ventilating the home should 

 be considered together, because the method of ventilation 

 depends on the method of heating and should be arranged 

 for at the time that the heating system is put in. Much 

 can be done later to ventilate the house, however, even if 

 no provision was made for it when the house was built. 



DEMONSTRATION 5 



Purpose. To study the composition of air. 



Apparatus. Candle, cork, plate, tumbler, limewater. 



Directions, i. Get a cork stopper a little larger than the 

 diameter of a candle. Cut off a piece about half an inch thick 

 from the large end. In the center cut a hole big enough to 

 receive a short candle about an inch long. Float this in a plate 

 full of water. The experiment can be seen better if a few drops 

 of red ink are added to the water. Light the candle and after 

 it is burning well, invert the glass tumbler over it. Allow to 

 stand for a while after the candle goes out. Why does the 

 candle go out? What happens to the water in the tumbler? 

 The water rises to take the place of the oxygen used by the 

 c 17 



