144 DOMESTIC WATER SUPPLIES FOR THE FARM 



the necessary supplies from wells. This is true also of many 

 areas underlain by clay and of some areas characterized by thick 

 beds of clayey till. In all these regions supplementary supplies 

 of water are necessary, at least for stock, and where springs, ponds 

 or lakes are not available cisterns must be resorted to, and in 

 some places they are necessary even for domestic supplies. 



Rain water is the softest of all natural waters, hence is very 

 desirable for washing and other domestic purposes, especially in 

 limestone regions, where the water of many wells or springs is so 

 hard that soap, instead of dissolving and making a good lather, 

 forms a dirty-looking curd or scum on the surface. In such 

 regions much trouble is also caused by the formation of thick 

 crusts of lime and magnesia on the inside of the kettles and other 

 utensils and by the precipitation of the white, milky sediment 

 which clouds the water when it has been boiled. In other regions, 

 as in parts of Florida and certain desert regions, the water may be 

 highly charged with soda, with the result that rice or other white 

 foods cooked in it are turned a dirty yellow. Elsewhere, espe- 

 cially on low sandy beaches and the keys of our limestone coasts, 

 the well water is brackish and unfit for drinking. All these 

 difficulties are avoided if soft cistern water derived from the 

 collection of the rain water is available. 



It is usually impossible for pollution to enter a properly con- 

 structed cistern one in which the lining is water-tight - 

 through the walls, and with a little care and by providing water- 

 tight covers it is possible to keep out much of the undesirable 

 matter from the top. Of course more or less dirt may be washed 

 from the roof into the cistern, but the first run-off can be allowed 

 to waste either by some automatic appliance or by hand, letting 

 only the later and relatively pure water enter the cistern. A 

 cistern, therefore, if properly made and cared for, is to be regarded 

 as a practically safe source of supply. It is certainly far safer 

 than the ordinary dug, bored and punched well, and even than 

 many of the shallower driven wells. 



Another great advantage of cisterns is their convenience. As 



