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DOMESTIC WATER SUPPLIES FOR THE FARM 



well, the only escape for the air is upward between the air- 

 pipe and the casing. As it rises, the water is carried along with 



it and is forced out at the top of the well 

 (Fig. 58). 



The effectiveness of the method is 

 greatest when the water normally reaches 

 within a few feet of the surface and de- 

 creases as the level of the water becomes 

 lower. When the water in the well stands 

 less than half way to the top, the air lift 

 can not be used to advantage. 



Hydraulic Rams. While the methods 

 of raising water previously described all 

 require some form of power, either man- 

 ual or mechanical, the hydraulic ram has 

 the advantage of utilizing the water itself 

 as its motive force. Its use, however, is 

 necessarily limited to artesian wells of 



FIG. 58. Diagram showing 

 principle of air lift. 



considerable head or to flowing wells or springs so situated that 

 a material fall is available for operating the ram. In case of 

 flowing wells the common practice is to connect the supply pipes 

 leading to the rams directly with the casings; at springs the 

 water is impounded in small reservoirs from which it is led 

 through a strainer and supply pipe to the ram. 



Only a few feet of head are necessary to operate such a ram, 

 and if a sufficient supply is available it offers a very satisfac- 

 tory means of raising the water. There is, however, always a 

 very large loss. When the height to which the water is raised is 

 only twice as great as the head, the efficiency may be as high as 

 86 per cent, but in raising it to higher points the efficiency rapidly 

 decreases. When it is raised a distance equal to ten times the 

 head the efficiency is only 54 per cent; when it is raised more 

 than 25 times the height of the head the proportion of water 

 pumped becomes small compared with that wasted. The wear 

 and tear on the ram is also considerable when the head is over 



