224 Introduction to the Study of Science 



react to soap? What effect has boiling upon its hardness? What 

 means are commonly used to soften water? 



Is the water clear or colored ? Let a quantity stand in a glass for a 

 while, and examine for sediment. What kind of sediment is precipi- 

 tated, sand, clay, or vegetable matter? Evaporate about 100 grams 

 of water in a glass beaker to find dissolved matter. When the water 

 is nearly boiled away, remove flame or put beaker on a sand bath. 

 Is there sediment? 



Has the water any odor? The simplest way to test for odor is to 

 fill a bottle which is perfectly clean and odorless about two thirds 

 full, shake vigorously, and then smell immediately when the bottle is 

 unstoppered. Has the water an odor when warmed? Fill a beaker 

 nearly full, cover closely with glass cover and heat gradually. When the 

 water is hot, remove from heat, and as you lift the cover, smell the 

 vapor in the glass. If the water has odor, it indicates the presence 

 of undesirable materials, living or inorganic. A rank odor like that 

 from decaying matter is evidence of the presence of organic matter. 



C. Has the water good pressure as it comes from the faucet? Is 

 the pressure sufficient for fires and other emergencies? Is it due to 

 the natural pressure, caused by the altitude of the reservoir which sup- 

 plies the distributing mains? If mechanical means are employed to 

 secure pressure, find out what they are and how regulated. If there 

 is a water tower in the system, explain its operation. What conditions 

 reduce the original pressure due to gravity or altitude of distributing 

 reservoir? . 



D. At what distance is the source of supply from the community? 

 What is the character of the intervening country? Describe the 

 conduits, their course, and capacity. 



What kind of water source is used? Is it surface, as stream, shal- 

 low well, or lake, or is it ground or deep water, as deep well or spring? 

 Describe the collecting and conserving reservoir; its construction, 

 capacity, and elevation above places of distribution. Is there any 

 vegetation growing in the reservoir? Is there much of it? Of what 

 kinds? Do you find algae or other weeds growing in the water? 

 The presence of algae is very important (cf. page 220). Why? What 

 animals, if any, occupy the water? What effect do you suppose they 

 may have on its purity or safety for domestic use ? If fish is abundant, 

 is fishing in the reservoir allowed? Do you think this practice would 

 have any influence upon the quality of the water ? 



E. What measures are taken by the community to prevent the 

 pollution of the water and watershed? Is there a regular patrol? 

 What power is vested in the patrol ? 



