COMPOSITION AND TESTING OF WELL WATERS 163 



for use in portions of New England rank not only as "usable" but 

 even as "good." Thus the Hartford Steam Boiler Inspection 

 and Insurance Company, on the assumption that half of the total 

 mineral matter present is in the form of incrustants, classes water 

 containing up to about 15 grains per gallon (250 parts per million) 

 as good, and that carrying from 15 to 30 grains per gallon (250 

 to 500 parts per million) as usable. In the West even more 

 mineralized waters are frequently used in boilers. 



Harmless and Harmful Ingredients. - - The ordinary mineral 

 ingredients in water, including lime, magnesia, silica, iron, etc., 

 are usually harmless in the quantities in which they are commonly 

 present, although slight digestive disorders are sometimes pro- 

 duced in susceptible persons on changing from soft to hard waters. 

 Waters that carry salt or iron enough to be tasted, those that are 

 strongly sulphurous and those which are charged with alkali are, 

 however, unsuitable for domestic uses, although often used for such 

 purposes. Occasionally waters are found that are high in magne- 

 sium sulphate (Epsom salts) or other "medicinal" salts, but it is 

 needless to say that the habitual use of such waters is highly 

 undesirable. 



In general, waters that are without taste may be regarded as 

 free from mineral matter in harmful amounts, but this is by no 

 means true as regards bacteria and polluting matter. The clear- 

 est, coldest, most sparkling waters may be crowded with typhoid 

 or other disease bacteria, and charged with seepage from cess- 

 pools and privies without the polluted condition being indicated 

 in the slightest degree, either by taste or appearance. Ingredi- 

 ents of this character, though unapparent and often even unsus- 

 pected, are unwholesome and harmful, and render the use of the 

 water highly dangerous. 



When Well Waters Should be Suspected. When well waters 

 which are usually clear become roily, when any objectionable or 

 unusual taste develops in previously tasteless waters or when an 

 examination shows sources of pollution in the form of privies, 

 cesspools, barns or hogpens within short distances 150 feet or 



