172 



MARKET DAIRYING 



Water from the upper pervious stratum should be 

 avoided wherever possible, even with wells of the kind 

 just described. Especially is this necessary where the 

 wells are shallow. The purest water is obtained by sink- 

 ing the well through an impervious stratum, like that 

 shown in Fig. 62. 



The most dangerous well is the common dug well with 

 pervious walls and so located as to permit seepage into 

 it from outhouses, barnyards and cesspools. Wells of 

 this type are altogether too common on dairy farms. 



Fig. 63.— Sources of Well Water Containinatiou. (From Bui. 143 Kau. 

 Exp. Sta.) 



All wells, whatever their construction, must be provided 

 with water-tight metallic or concrete covers to prevent 

 the entrance of impurities into the shaft. 



ICE SUPPI,Y. 



Necessity of Ice. Where there is no equipment for 



