CHAPTER XXXVII 



THE WORK OF RUNNING WATER 



The solvent action of water. The power of water in stream, 

 lake, and ocean is evident to all, but the activity of ground 

 water, that is, rain water which sinks into the earth and moves 

 through it, is not so generally known. The real activity of 

 ground water is due to its power to dissolve minerals and gases. 

 When rain falls it dissolves substances floating in the atmosphere, 

 and when it sinks into the ground it dissolves materials out of 

 rocks. A proof of the presence of mineral matter in water is 

 seen in the crust or coating which accumulates on the inside of 

 a kettle in which water is boiled. The crust is an accumulation 

 of minute particles of mineral matter which was left behind 

 when the water evaporated. 



The abundance of ground water beneath the surface of the 

 earth is shown by the numerous springs which gush out of 

 the ground and by the numerous wells which supply water. 

 Springs and wells fed by waters rich in minerals are called 

 mineral springs and mineral wells. The quantity of mineral 

 matter in some springs is surprisingly large. The famous 

 springs of Bath, England, contain so much mineral matter 

 in solution that a column 6 feet in diameter and 140 feet 

 high could be built out of the mineral matter contained in 

 the water consumed yearly by the townspeople. A German 

 spring yields water from which enough salt could be taken in 

 a year to fill completely a good-sized house. There are many 

 mineral springs in the United States ; among the best known 



357 



