EUNNING WATER FOR FARM BUILDINGS 431 



causes of disease. The same thing applies to the shallow well, as 

 it is very apt to receive impurities from the surface of the 

 ground which have not passed through enough earth for proper 

 purification. Usually the best source of all is the deep well, as 

 the water from this source is safe and in most cases cooler and 

 more palatable. Springs and lakes are just as satisfactory, how- 

 ever, and sometimes more so if the water is found to be pure. 



a. Slialloiv ivells. — In this chapter shallow w^ells are consid- 

 ered as those in which the water level is near enough to the 

 surface of the ground so that water can be drawn up by suction ; 

 sjirings, cisterns, lakes and rivers can come under this head in 

 selecting the equipment. The suction lift is usually considered 

 about twenty feet, but it is a quantity that will vary with the 

 atmospheric pressure of the locality, being practically twenty- 

 two feet at sea level. The best practice is to eliminate the suc- 

 tion lift, if possible, by having the cylinder under water ; in no 

 case is it good practice to have the cylinder more than twenty- 

 two feet above the water level. With pumps which have the 

 cylinder separate from and below the standard, the most com- 

 mon type, the distance from the surface of the ground to the 

 water level can be more than twenty feet as the cylinder will be 

 below the surface. The cylinder is the pump proper, and all 

 distances should be measured from it. 



h. Deep ivells. — Deep wells are considered as those in which 

 the water is too far below the surface of the ground to be drawn 

 up by suction. In these wells it is always necessary to have the 

 cylinder and standard separate, connected by a section of pipe. 

 The length of this pipe should be sufficient to bring the cylinder 

 within suction distance of the water. Here again, however, the 

 best practice is to have the cylinder below the water level, as 

 this keeps the cylinder primed and the valves will not dry out if 

 the pump is not used for a long time. 



c. Location and coyistruction. — In providing a well there are 

 two important points to be considered: First, its location; sec- 

 ond, its construction. Both of these factors Avill affect the purity 

 and liealthfulness of the water obtained. If the water is taken 

 from a shallow well, the well should be at least thirty-five or 

 forty yards from any barn yard, cesspool, vault or other source 

 which might contaminate the water by seepage througli the soil. 

 If possible, it should be always located on higher ground than 

 these impurities so the natural flow of water will not be from 

 them toward the well. A\niere a deep cased well is used, the 

 danger of contamination is practically eliminated. For this 



