OF ARTS AND SCIENCES. 75 



" These results show, — 



" 1st. The immediate effect of the salt in preventing the action on 

 lead by lessening the solvent power for air ; and 



"2d. The influence of salt in dissolving the coat formed, by double 

 decomposition, or by the formation of the double salt of the oxide and 

 chloride ; as shown in the last suite of results. 



'•The preceding experiments, as a whole, go to show that Cochituate 

 water may be distributed through iron mains and leaden service-pipes 

 with as little danger as Schuylkill, Croton, or Jamaica water. 



" The consideration that was to give value to these determinations 

 was that of the health of the citizens of Philadelphia, New York, and 

 Boston, so far as it might be influenced by the waters served through 

 lead in the respective cities. This was to be decided, as already in- 

 timated, by an appeal to the most enlightened testimony that could be 

 furnished ; that of eminent physicians of extensive practice in the 

 localities where lead pipe is employed." 



Professor Horsford then adduced a summary of the nu- 

 merous medical opinions, chiefly compiled from letters ad- 

 dressed to himself, and which have been already published 

 in the Appendix to the Water-Commissioners' Report of Au- 

 gust 14th, 1848. 



" The decision of this question does not depend upon the presence or 

 absence of a minute quantity of lead in water that has been standing 

 a given length of time in leaden pipes, or upon the absolute freedom 

 from corrosion of pipes long in use. For if a certain quantity, more 

 or less, has found its way into the human system in the every-day 

 regular use of Croton and Schuylkill waters, then must the human 

 system be capable of sustaining without injury this quantity ; and the 

 possibility of receiving an equal quantity hereafter by those who drink 

 Cochituate water may be contemplated whhout solicitude, since the 

 experiment has been made.* Nevertheless, examinations for lead 

 have been made in many well-waters, and also in Croton, Jamaica, 

 Schuylkill, and Troy waters, and Dedham spring water. The results 

 follow. 



* To this point more particular reference will hereafter be made. 



