CHAPTER VI 



WATER 



65. Destructive Action of Water. The action of water in 

 stream and sea, in springs and wells, is evident to all ; but 

 the activity of ground water that is, rain water which sinks 

 into the soil and remains there is little known in general- 

 The real activity of ground water is due to its great solvent 

 power ; every time we put sugar into tea or soap into water we 

 are using water as a solvent. When rain falls, it dissolves sub- 

 stances floating in the atmosphere, and when it sinks into the 

 ground and becomes ground water, it dissolves material out 

 of the rock which it encounters (Fig. 30). We know that water 

 contains some mineral matter, because kettles in which water 

 is boiled acquire in a short time a crust or coating on the in- 

 side. This crust is due to the accumulation in the kettle of 



mineral matter which 

 was in solution in the 

 water, but which was 

 left behind when the 

 water evaporated. (See 

 Section 25.) 



The amount of dis- 

 solved mineral matter 

 present in some wells 

 and springs is surprisingly great ; the famous springs of Bath, 

 England, contain so much mineral matter in solution, that a 

 column 9 feet in diameter and 140 feet high could be built 



70 



FlG. 30. Showing how coves and holes are 

 formed by the solvent action of water. 



