275 



The purity of water is not simply a matter in wliich is involved liealth 

 and convenience in domestic economy ; for, to the manufacturer, where 

 water is used as a solvent, it is exceedingly important that it should be 

 pure. " Brewers often go to an enormous expense in boring deep wells, 

 in order to obtain a supply of soft water, for extracting all soluble 

 matter from the malt and hops they employ. Dyers, also, bore wells, 

 in order to obtain a supply of soft water, as certain colors cannot be 

 dyed, where water, containing the ordinaiy impurities, comes in contact 

 with the dye-stuffs. Bleachers, again, require pure water ; and many 

 other branches of manufacture might be mentioned, where pure water 

 is absolutely indispensable." 



You have requested me to direct my particular attention to the pro- 

 priety of using lead service pipe, in the conveyance of river water. I 

 approach this subject with great reluctance, for I am well aware of the 

 important bearing it has upon the health of your city, and equally well 

 aware that, at present, there is no little discrepancy of opinion among 

 scientific men, as to the circumstances in which lead pipe may be safely 

 used. This disagreement arises, in part, from the difficulty in determin- 

 ing, precisely, what water does not corrode lead, and, in part, from the 

 evil effects of the lead on the system, so nearly resembling diseases pro- 

 duced by other morbific agents, as not always to be clearly distinguish- 

 able from them. Not having made any experiments myself to deter- 

 mine the action of water on lead, except in the case of rain water, I 

 shall be compelled to rely on the experiments and views of others. I 

 have already deprecated the use of lead pipe for the conveyance of 

 rain water. No one will question the impropriety of thus iising it, It 

 is said, however, that most spring and river water contains a sufficient 

 quantity of the neutral salts, to form an insoluble lining on the inner 

 surface of the pipe, which most effectually protects it from further de- 

 composition. Thus, Dr. Christison states, that "water containing 1-000 

 or^l-1200 part of salts, may be safely conveyed in lead pipe, if the 

 salts are chiefly sulphates and carbonates, and that lead pipes cannot 

 be safely used when it contains 1-40 00th part of saline matter, if this con- 

 sists of muriates." 



At the request of the Board of Consulting Physicians of the City of 

 Boston, Professor E. N. Horsford, of Cambridge, in 1849, examined 

 with great care, the relations of lead to air and water, and gives the 

 following as his conclusions : 



