No. 4.] FAR:\I water supplies. 317 



and prevent animals or objectionable matter from falling 

 into it. 



The best protection — and usually sufficient — for a well is 

 to lay the upper 5 feet of the stone curbing in cement mortar, 

 carrying the curbing to a few inches above the level of the 

 ground, so that surface water will be diverted from the well 

 and cannot enter it at the top. A cover should be placed over 

 the well or upon sills of joist set in cement on top of the curb. 

 A small box or pipe rising above the platform and with an 

 opening in its sides will provide sufficient ventilation, but it is 

 important that the opening should be screened with fine wire. 



If water is drawn from the well by a pump passing up 

 through the platform it is highly important that the platform 

 be made absolutely tight and so sloped that water falling upon 

 it will be carried away from the well. One of the most serious 

 dangers of pollution of a well is water washing from dirty boots 

 upon the platform. 



Effect of Lead Pipe. 



If the water is drawn through a pump and a suction pipe 

 placed in the well it is best to avoid the use of lead pipe, since 

 many ground waters act rapidly upon lead and cause lead 

 poisoning. A pipe of block tin or of lead lined with tin, pro- 

 vided the pipe is made wholly of tin or of some suitable ma- 

 terial where it is in contact with the water in the well, will be 

 safe for use. Pipes of iron lined with tin, or especially with 

 cement, are also satisfactory for conveying drinking water. 

 Galvanized iron pipes are usually satisfactory, but waters which 

 attack lead usually attack iron and, by taking up an excess of 

 iron, make the water objectionable for many domestic pur- 

 poses. 



One other matter should be mentioned, and that is the im- 

 portance of avoiding the heavy manuring of land in the imme- 

 diate neighborhood of a well. This practice has been known to 

 affect the water of many wells otherwise good, and it should be 

 carefully avoided for a space of 100 feet or more from the well, 

 especially on the side from which it derives its supply. 



It is not practicable within the limits of this paper to go 

 into the question of well-water analysis except in the most 



