220 PROCEEDINGS OF THE AMERICAN ACADEMY 



On the 27tli of March, 1874, the superintendent of the works again 

 wrote as follows: — 



" "VVe enclose specimens of the lining of the tank which contained 

 the water, the purity of which we were suspicious. We may be mis- 

 taken, but it does seem to us that the lining has been destroyed by the 

 action of the water, in a most unusual manner. The tank lining has 

 lasted only five years. There has been a free and ample circulation 

 of fresh water constantly in use in the daytime, at the hotel, where 

 our tank is located ; and yet, for some cause unaccountable to us, the 

 lining (which is block-tin) is perfectly riddled by corrosion, and must 

 be replaced by a new one of some kind." 



In answer to further inquiries on my part, he forwarded another 

 specimen of the water, and a large piece of the lining of the tank, and 

 further wrote : — 



" The water is collected at the spring, in a sheltered and ventilated 

 reservoir, with cement lining, and is conducted therefrom in a large 

 cement pipe through our main streets. House pipes of lead are at- 

 tached all along." 



The water from the end of the pipe, where it discharged^ into the 

 tank, was again analyzed, with the following results : — 



Inorganic matter, 4.20 ; organic matter, 0.80 parts, in lOOjOOO. Was 

 perfectly free from nitrates ; and, as the analysis shows, was rather 

 better than when first examined. The lining is commercial block-tin, 

 containing less than 2 per cent of impurities. 



Instances of corrosion of lead are not uncommon ; but I have failed, 

 so far as I have investigated, to find a case parallel to this. Professor 

 Chandler,* in an article on the use of tin-lined lead pipe, says, in speak- 

 ing of tin-lined lead pipe : " Waters which take up one to two tenths 

 a grain per gallon from lead pipe are not perceptibly affected by re- 

 maining for considerable lengths of time in the tin-lined pipes." And in 

 another place, Mr. Cassamajor f states that tin is slightly more electro- 

 negative than lead; and that it at first starts a feeble galvanic current, 

 which serves to cover the lead with a coating of oxide, and then all 

 action ceases. 



Dr. Lankester t states, in regard to the tin-lined lead pipes : " I have 

 tested these pipes with great care, and have exposed them to the action 

 of water of various kinds. In no case have I discovered in the water 

 the slightest trace of lead or tin. I have submitted the pipes to the 



* Am. Chem., Vol. II. p. 282. t Am. Chem., Vol. I. p. 3. 



i Am. Chem., Vol. II. p. 27. 



