450 DRY LAND FARMING 



impervious clay furnishes a cheaper material. By a 

 process sometimes spoken of as "puddling" it is made 

 to prevent the seepage of water very effectively that 

 would otherwise take place through materials such as 

 are often used in the construction of dams. 



When making such reservoirs the fact should not 

 be lost sight of that under many conditions fully 50 per 

 cent, will be lost by evaporation. The proportional loss 

 from this source will not be commensurate with the 

 capacity of the reservoir. The more shallow the reser- 

 voir in proportion to its capacity, the greater will be 

 the loss from evaporation, because of the relatively larger 

 amount of the water surface that is thus exposed. 



Water may be conveyed from distant springs in 

 many instances at a cost for the piping that is within 

 the means of the farmer. But when so conveyed it 

 ought to be gathered into a reservoir. This will prove 

 a safeguard against any interruption in the conveyance 

 of the same, as may temporarily occur. 



How water may be raised. In dry areas water may 

 be raised: (1) by wind power; (2) by gasoline power; 

 (3) by steam power, and (4) by electrical power. Which 

 of these should be employed will depend largely on the 

 cost entailed and on the amount of the water to be 

 raised. 



Where it is necessary to raise only small quantities 

 of water wind power will suffice. Such power will 

 answer as a rule to supply the needs of the household, 

 whether the source of the supply is a well, a reservoir 

 or an irrigating ditch. It will also suffice to raise enough 

 water for live stock in many instances where this may 

 be necessary. It may also be made to raise water for a 

 few acres of garden and orchard land when this may be 

 desired. The capacity of the mill called for will be 

 largely dependent, first, on the amount of water to be 

 raised, and, second, on the average velocity of air cur- 



