SOILS, FERTILIZERS AND IRRIGATION 69 



must be considered. They are : a cylinder in the well, a number of feet 

 of pipe from this cylinder to the point of discharge, a pumping head, 

 either geared or belted to an engine or motor, and a gas engine or motor. 

 For a supply of 15 gallons a minute and a lift of 100 feet the cost would 

 be as follows : 



Cylinder $ 9 to $14 



100 feet of pipe at 12c 12 



Pumping head 14 to 25 



Ij^-horsepower gas engine 75 



Approximate cost $125 



For a supply of 70 gallons a minute and a lift of 100 feet : 



Cylinder $20 



100 feet of pipe at 20c 20 



Pumping head 60 



5-horsepower gas engine 150 to $350 



Or 5-horsepower motor 68.10 



Approximate cost $250 to $450 



(Running cost probably more.) 



Gasoline used would be about one-fourth gallon per horsepower per 

 hour. 



For irrigation purposes one is again controlled by the amount of 

 water needed and of money to be invested ; the number of acres to be 

 irrigated, the local rainfall and its distribution, and the number of feet 

 the water is to be lifted. A centrifugal pump would probably be chosen 

 in this case. The cost varies with the quantity of water required and 

 the distance it is to be lifted. Doubling the lift or quantity of water 

 handled also doubles the power required and the cost rises in proportion. 

 With a centrifugal pump it is necessary to dig a pit to the water surface 

 in the well, as it is not advisable to suck water over a suction-lift of from 

 20 to 25 feet to the pump. The price of the digging varies with the size 

 and depth of the pit from $1.00 per foot up. The water level controls 

 the depth of pit. We shall figure on a discharge of 200 to 225 gallons 

 a minute which is sufficient to cover one acre six inches deep in a twelve- 

 hour run, not allowing for loss by seepage. Based on a pump efficiency 

 of fifty per cent with a lift of 30 feet a discharge of 200 gallons a minute 

 may be obtained with 3 horsepower, while with a lift of 100 feet, 10 

 horsepower will be necessary to discharge the same amount of water. It 

 is simply a question of power, lift and quantity required. Doubling the 

 lift or doubling the quantity doubles the power needed. With the 30-foot 

 lift one would use a No. 3 horizontal centrifugal pump, which pumps 

 about 225 gallons per minute and costs from $100 to $150. A 5-horsepower 

 gas engine or motor would be used with this lift and size of pump. The 

 engine varies in price from $200 to $350, but the initial cost is a small 

 item compared with economy in operation as time goes on. There are 

 engines on the market costing $350 which consume only one-half gallon 



