WATER SUPPLY 



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4. Impure water is dangerous. 



5. Impure water is expensive. 



6. Ground-waters must be protected. 



7. Surface-waters must be purified. 



8. Qualities to be sought in water wholesomeness, cleanliness 

 and softness. 



9. Filtration makes water clean. 



10. Filtration makes water safe. 



11. Filtration has been justified by experience. 



12. Hard water may be softened. 



, PIG. 188. A closet showing trap. 



QUESTIONS.. 



1. What is the ntolTt dangerous source of water pollution? Why? 



2. What objections can be given to the use of hard water? 

 Soft water? 



3. Why should water from the hot water boiler never be used for 

 drinking water? 



4. What precautions must be taken if water is obtained through 

 lead pipes? 



5. If you get a drink early in the morning at a drinking fountain 

 what should you do first? 



6. Give two reasons why the lips and the teeth should never 

 touch any part of the fountain. 



