\Ynters. li'.i 



I)' Shallow wells (penetrating but one geological stra- 

 tum), 



Deep wells (passing through more than one such 

 stratum) . 



3. Surface ivaters consisting of 



(a) Flowing waters (streams). 



(b) Still water (ponds, lakes, etc. 



4. NM/ irnler. 



Rain water. The composition and character of this has al- 

 y been described in Chapter II. It contains very little min- 

 ral matter and is described as "soft" for this very reason. If it 

 ould be collected without further contamination it would be by 

 far the best for most purposes. The acidity of the rain in dis- 

 3 where much coal is burned is of great importance as affect- 

 lie growth of plants, particularly grasses and certain trees. 

 In addition to its direct injurious effect upon the foliage, it 

 a a deleterious action upon the soil, tending to remove the 

 alrium carbonate or other basic material and to promote "sour- 

 a condition which is very unfavorable to the growth of 

 useful plants. It is known that grass lands under such 

 Distances become almost sterile, the last plants to 'succumb 

 .< unfavorable conditions being usually the "sorrel" or 



! dock.'' 



Ground Water. The water issuing from springs varies great- 

 ly in the amount and nature of the dissolved matter whiclj it con- 

 tains, If this be small, and not possessed of strong odor, or taste, 

 ater is described as fresh water; but if a large quantity of 

 v-d matter be present, or if the water possesses pronounced 

 "doi-. or medicinal properties, it is known as a mineral 



Many spring waters contain the following substances, but in 

 varying amounts: 



Calcium and magnesium carbonates dissolved in excess 

 "f carbon dioxide. 



Calcium or magnesium sulphate. 



