310 



Irrigation and Drainage 



The very large sizes of hydraulic rams may also be used 

 on streams of relatively small fall for lifting water for the irri- 

 gation of small areas, especially if used in connection with 

 reservoirs. They are very simple, relatively cheap, durable, and 

 require but little attention. The ramming engines, Fig. 69, are 

 similar to the hydraulic rams, but are built larger and have 

 greater capacities. They are more complex in structure, and 

 more expensive. The engine represented in the figure is said to 

 be able to elevate water to a height of 25 feet for every foot of 

 fall, or to deliver one -third of the water used in its operation at 



Fig. 70. Siphon elevator. (Wilson, U. S. Geol. Survey.) 



two and one-half times the height of the fall, and one-sixth of the 

 water at five times the height of the fall. Those having a drive 

 pipe 8 inches in diameter and a delivery pipe of 4 inches are 

 capable, under a head of 10 feet, of elevating about 6 acre- inches 

 to a height of 25 feet in 24 hours, and this will irrigate 24 acres at 

 the rate of 2.5 inches every 10 days. Such an engine will cost 

 $500 (Wilson). 



The siphon elevator, represented in Fig. 70, is an appliance 

 utilizing the principle of the hydraulic ram in connection with a 

 siphon. The amount of water lifted by this varies with the dimen- 

 sions of the appliance, the height to which the water is lifted, and 

 the difference between the lengths of the two legs of the siphon. 

 It can only be used where there is a dam, or similar condition, 



