WINDMILIyS AND PUMPS. 363 



Strokes of the pump in proportion to the revolutions of 

 the wheel, so as to utilize the greater force of the wind 

 obtained by higher velocity than fifteen miles, and are 

 adjusted to govern at a considerable higher velocity 

 than ungeared mills. 



Twenty-seven thousand one hundred and fifty-four 

 gallons of water will cover an acre one inch in depth. 

 One horse-power, with good machinery, will raise this 

 amount of water one foot high in ten minutes; or ten 

 horse-power will raise it in one minute. One horse- 

 power would put one inch of water on one acre, elevated 

 twenty-five feet above the source, in four and one-sixth 

 hours. Ten horse-power would do the same for ten 

 acres. Now from this we get the rule that, for one 

 inch of water on one acre of land, we must figure one 

 horse-power for ten minutes for each foot in hight the 

 water must be raised. It may be more explicit to add 

 that one horse-power is defined as the combined pulling 

 strength of four ordinary horses. In theory a horse- 

 power is equal to 33,000 pounds lifted one foot high in 

 one minute of time. 



Capacity of Windmills and Reservoirs. — The 

 only question with people in general adopting wind- 

 mill irrigation is one of proper storage and handling of 

 the water. The double reservoir system will be neces- 

 sary. The figures given for sizes of reservoirs are for 

 holding the water for twenty-four hours continuous 

 pumping; but larger reservoirs should be made of from 

 one to two acres in extent, carrying from 8 to 10 feet 

 of water. 



Extra reservoir required to reserve overflow after 

 twenty-four hours' pumping should be of one and two 



