BREATHING AND VENTILATION 



WINDOW VEN- 

 TILATION WITH- 

 OUT DRAFTS 



cent of carbon dioxide. Gas-lights and open fires consume 

 much oxygen and give off carbon dioxide. To remove the 

 carbon dioxide produced by breathing and 

 by lights and fires, and to keep a continu- 

 ous supply of oxygen, it is necessary to have 

 openings for the air to enter our rooms. 

 Each person should have about 300 cubic 

 feet of fresh air every hour. Gas-lights 

 and fires need more. In an ordinary- 

 sized room of a home 10,000 cubic feet of 

 air can be allowed to enter each hour 

 without danger of a draft. Air must move 

 three or more feet per second before it can 

 be felt as a draft. If air is moving three 

 feet per second through an opening with an area of one 

 square foot, 10,800 cubic feet of air would enter each 

 hour. Where there is no system of ventilation in a 

 building, the windows should be lowered from the top, 

 or the lower sash raised and a board placed under it so 

 that the air will have to come in between the two sashes, 

 thus giving it an upward direction. The windows of 

 sleeping rooms should be kept open when they are 

 occupied. 



QUESTIONS AND EXERCISES 



1. Compare the chest and shape of the shoulders of those who 

 take breathing exercises and those who do not. 



2. Observe those who breathe through the mouth and see how 

 it affects their appearance. 



3. What should be done if children are found breathing through 

 the mouth? 



4. Who is more liable to get dust and disease germs into his 

 lungs, one who breathes through the mouth or through the nose? 



5. How do you ventilate your home? Your sleeping room? 



