IRRIGATION 233 



falling a short distance, to elevate a portion 

 of the water to a greater height. It is 

 wasteful of water, but when a never-failing 

 stream of sufficient flow and fall is avail- 

 able it is one of the most economical and 

 satisfactory of water-lifting machines. 



Rams are somewhat difficult to install by 

 a novice, because of the rather exacting con- 



Fig. 123. Plan for installing a hydraulic ram 



ditions necessary to secure the most efficient 

 service. When they are properly installed, 

 however, they give little trouble, provided 

 they are kept from freezing. 



Capacity of Rams. To find the capacity 

 of a ram for any given conditions proceed as 

 follows : Multiply the fall in feet by the quan- 

 tity of water which may be supplied to the 

 ram in gallons per minute, and divide the 

 product by the height the water is to be 

 raised. The result will be the number of 

 gallons delivered per minute. The above 



