Water 57 



the water flows contains any soluble mineral matter, the water 

 often collects it and carries it along in solution. Such springs 

 are called mineral springs. Water from some of these springs is 

 used in great quantities as medicine. There are about 300 mineral 

 springs in the United States where the water is sold in the belief 

 that it promotes health. 



The waters of mineral springs are classified according to the 

 minerals dissolved in them. Among the well-known springs where 

 these mineral waters are found are the hot springs of Virginia, the 

 saline and the alkaline springs of Saratoga, New York, the white 

 sulphur springs of Ohio and the alum springs of Virginia. The 

 waters of some of these springs, as at Saratoga, also contain 

 small amounts of iron, carbonate of lime and other substances 

 with only a trace of organic matter. Thousands of people visit 

 Saratoga each year for the purpose of drinking these health- 

 giving waters. 



Artesian Wells. Artesian wells received their name from 

 Artois, a province in France, where they were first developed. An 

 artesian well is a well from the top of which water flows con- 

 tinuously. At times it even spouts many feet into the air. Such 

 a well may occur in regions where underlying rock is in layers 

 and where there is a porous layer between two solid layers. The 

 water collects in and flows through the porous layer, held in 

 by the hard layers. 



If these layers of rock do not lie horizontally they will come to 

 the surface somewhere. If this should be where the land is 

 high, as in a mountain range, the rain from that point will fill 

 the porous layer. The solid layers will confine this water to the 

 porous layer and it may flow through the pores for many miles 

 and often at great depths. If a hole is bored down to the porous 

 rock at any point where the country is lower than where this 

 layer receives the water, the water will flow out the top of the 

 hole on account of the pressure caused by the weight of the water 

 in the higher levels in this same porous rock. 



Water that comes from these wells is usually of excellent 

 quality, free from disease germs, and therefore desirable for 

 drinking purposes. It nearly always contains mineral matter, 



