73 ILLINOIS ACADEMY OF SCIENCE 



Ninety-nine samples were examined for turbidity. Of these 

 70 showed a turbidity less than 5 parts per million; 82 less 

 than 10; 69 less than 15, and only 10 showed 15 or more. A 

 turbidity below 10 would not make the water appear unattrac- 

 tive and it would seem not unreasonable to require a standard 

 of 10 or less. 



Ninety-nine samples were examined for color. Seventy- 

 nine of the samples had a color less than 5 parts per million; 

 88 less than 10; 93 less than 20, and only 6 had 20 or more. 

 A color requirement of 20 or less should be easy to meet and it 

 would not be impossible to meet a requirement of 10 or less. 



Ninety-nine samples were examined for residue. Of these 

 28 had a residue less than 50 parts per million; 36 less than 

 100; 75 less than 200; 84 less than 300; 90 less than 400; 95 

 less than 500, and only 4 above 500. The very low residues 

 are undoubtedly due to the presence of melting ice in the cool- 

 ers. The few* samples containing more than 500 parts per 

 million would indicate that a standard of 500 or less could 

 easily be made. 



Chlorine was determined in 99 samples. Of these 46 had 

 less than 5 parts per million ; 66 had less than 10 ; 75 had less 

 than 15 ; 82 had less than 20; 90 had less than 25, and only 9 

 more than 25 parts per million. It should not be difficult to 

 obtain a water containing less than 15 parts of chlorine per 

 million and it should certainly be easy to obtain water con- 

 taining less than 25 parts per million. In special cases where 

 it is not possible to obtain waters with low mineral content, 

 exceptions to the rule may be made. The same may be true 

 also of residue, magnesium, sulfates, alkalinity and hardness. 



Sixty-six were examined for magnesium. Of these 39 con- 

 tained less than 10 parts per million; 51 less than 15; 60 less 

 than 20, and only 6 more than 20 parts per million. In the 

 large majority of cases, therefore, it should be easy to obtain 

 waters containing less than 20 parts per million of magnesium. 

 If the magnesium were all present as sulfate, 20 parts of mag- 

 nesium wtould be equal to 100 parts of magnesium sulfate. 



The alkalinity using phenolphthalein and methyl orange as 

 indicators was determined in 99 samples. In only one case was 

 a water found which was alkaline to phenolphthalein. A re- 

 quirement that the alkalinity of phenolphthalein shall not be 

 greater than one-half the alkalinity to methyl orange would 

 be easy to fulfill and would guard against the use of water 

 over treated with lime. Forty-three samples contained less 



