WATER 



61 



Deep well waters are less liable to be contaminated with 

 organic impurities than surface wells, but a deep well is 

 not above suspicion because the layers of soil are subject 

 to changes in slope, and the water from a deep well may 



Fig. 31 Well contaminated with drainage from swamp. 



receive surface drainage from some distant place, as indi- 

 cated in the illustration (Fig. 31). Although the soil 

 would remove a portion of the impurities and the organic 

 matter would be partially oxidized, the water would not 

 be entirely free from contamination. 



64. Location of Wells. The well should be remote 

 from barns and cesspools. Large trees about wells are 

 objectionable because the water is fouled by waste matter 

 thrown off by the roots. The top of the well for 6 or 8 

 feet should be laid with cement. The well platform 

 should be tight so that small animals are kept out. 

 Drain water from the spout should be carried away from 

 the well platform and the watering trough should not be 

 directly over the well. The land should slope away from 

 the well and the surfacing should be of clay. The well 

 should have ventilation, and should occasionally receive 

 a cleaning. 



65. Mineral Impurities. Calcium carbonate, calcium 



