12 VREDENBURG : RECENT ARTESIAN EXPERIMENTS IN INDIA. 



These well-known features of artesian action are here alluded 

 Special advantages of to because it is important to keep sight of them 

 deep artesian sources. in discussing the capabilities of artesian wells. 

 As already pointed out, the fact of their flowing at the surface or 

 not is not of much importance, their usefulness, from a practical point 

 of view, depending on an abundant and constant delivery. When the 

 water is needed to supply a town for drinking purposes, it has this 

 further advantage that it is free from any germs of disease. It is not, 

 however, its applicability to domestic purposes that usually attracts 

 public attention to artesian resources, but people have generally 

 been struck by the achievements obtained in some countries where 

 they have supplied the needs of irrigation. In this respect, one 

 is apt to form an exaggerated notion of their capabilities. The 

 imagination is easily struck by such facts as the phenomenal 

 outflow of some of the North American wells, or by the creation 

 of artificial oases in the midst of the Sahara. But it is necessary 

 to keep in mind how very local these effects must remain, even at 

 their best, and the notion, sometimes entertained, that the sinking 

 of artesian wells would in the slightest degree afford relief during 

 Indian famines should at once be dispelled. 



It is principally in deserts that the use which it is possible to 

 _„. . , . . derive from artesian water is seen to its best 



Efficiency of artesian 



resources in deserts. advantage. In a desert, no cultivation can be 

 undertaken that depends merely upon rainfall, because the annual 

 precipitation is insignificant and precarious. Cultivation can only 

 be practised when that scanty rainfall, concentrated and stored by 

 natural or artificial means, is applied to irrigation. River systems 

 may collect from a large area so much of the rainfall as escapes 

 evaporation, and some of their stream-beds may thus carry a peren- 

 nial stream. When this reaches the plains, the water may be 

 diverted into artificial channels and devoted to irrigation. The 

 area thus cultivated is very small compared to that over which the 

 rain has fallen, but it is the application to a limited area of a large 

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