THE IRRIGA 2 ION AGE. 11" 



watering in spring. Most vegetable crops require watering in sum- 

 mer; also the orchards should be watered for the last time in July. 

 It is by general crop culture that Irrigation by wind mills and pumps 

 is to be made most profitable. 



The amount of land that can be irrigated, depends first, on the depth 

 to water and supply of water in the wells; and second, on the size of 

 wind mill and pump used. And when general crops are grown, so 

 that the mill and pump may work the year around, larger acreage can 

 be irrigated than when only truck farming is done. The same size 

 wind mill and pump will irrigate only one-half as much land when 

 water is raised 40 feet as when it is lifted only 20 feet, and only one- 

 quarter as much land when the vvater is lifted 80 feet as when lifted 20 

 feet. 



When low velocities of wind are to be used a smaller cylinder will 

 have to be used, that the mill may be able to operate the pumps. A 

 wind velocity below fifteen miles per hour furnishes so little power, 

 with any size of wind mill, that few persons care to use pumps so 

 small as to utilize the force of wind below fifteen miles per hour in 

 irrigation. Substantial wind mills may be adjusted to work in a wind 

 of thirty to thirty -five miles per hour, when the power of the wina is 

 four to five times as great as when the velocity is only fifteen miles 

 per hour. 



How to utilize this varying force is of the greatest importance to 

 those who use the wind to operate their pumping machinery. 



An irrigating wind mill can make twice as many strokes of the 

 pump in a 30 mile wind as it can in a 15 mile wind, and will conse- 

 quently pump twice as much water, but as its power is more thon four 

 times as great working in a 30-mile wind as it is in a 15-mile wind, it 

 should not only have doubled its work, but should have quadrupled 

 the amount done in the 15 mile wind. Hence it is readily seen that 

 to utilize all the force of the wind up to the point the mill had been 

 adjusted to govern at, two or more pumps must be employed, and as 

 many pumps connected up, as mill can operate with the force supplied 

 to the wind mill for the time being. A wind mill working under the 

 full pressure of a 30-mile wind has power to lift eight to ten times as 

 much water as when working under the force of a fifteen mile wind. 

 "To irrigate with wind mills and pumps implies that the time to pump 

 is when the wind blows. 



A complete wind mill and pump irrigating plant will consist of 

 one wind mill and two or more pumps. 



The reservoir should be constructed in an oblong form, i. e, 

 50x100 or 100x200, and so on. Then erect the wind mill near the em- 

 bankment on one side, midway between the two nds; this will admit 

 of operating one or more pumps on either side of the mill, by means 



