120 



FARM MECHANICS 



Well-water contains many impurities. For this rea- 

 son, it is likely to be valuable for crop growing pur- 

 poses in a wider sense than merely to supply moisture. 

 Well-water contains lime, and lime is beneficial to most 

 soils. It has been noticed that crops grow especially 

 well when irrigated from wells. 



Figure 128. Power Transmission. Circular motion is converted 

 into reciprocating motion by the different lengths of the two pitman 

 cranks which cause the upoer wheel to oscillate. Power is carried 

 to a distance by wires. To* reduce friction the wires are supported 

 by swinging hangers. Sometimes wooden rods are used instead of 

 wires to lessen expansion and contraction. 



House and Barns Supplied from a Reservoir. A 

 farm reservoir may sometimes be built very cheaply 

 by throwing a dam across a narrow hollow between two 

 hills, or ridges. On other farms, it is necessary to 

 scrape out a hole on the highest ground within reach. 

 For easy irrigation 'a reservoir is necessary, and it is 

 economical because the pump may work overtime and 



