OF ARTS AND SCIENCES. 219 



X. 



A SINGULAR CASE OF CORROSION OF A TIN TANK. 



By S. p. Shaeples. 

 Eead, May 12, 1874. 



In June, 1872, I received a letter from the Collins Company, of Col- 

 linsville. Conn., of which the following is an abstract : — 



This company has a hotel building in this place, supplied with very 

 good spring water, which is conducted through, say 100 feet of lead 

 pipe, from the cement jDipe main in the street, to a very large tank or 

 reservoir on an upper floor in the hotel. From this tank water is dis- 

 tributed all over the house, through lead pipes. "Water is continually 

 running into the tank, and of course is freely drawn oflT to the various 

 points. The tank is lined with what the plumber calls pure block-tin. 

 We observe that the water deposits white streaks, at various levels, 

 around on the lining. Enclosed we send you a specimen of the tin 

 lining and the white'deposits or powder. 



A waste pipe, 9 feet long by 2 inches in diameter, is within the tank, 

 and subject to the action of the water. 



Is the white powder from lead or any corrosive metal ? 



Subsequently they forwarded me specimens of the water taken from 

 the spring, from the place where the lead pipe discharged into the 

 tank, and from the place where it was drawn for use in the house. 



The water taken directly from the spring was examined, and gave 

 5.3 parts inorganic matter, and 2.5 parts organic matter, to the 100,000 

 parts of water. 



The inorganic portion was mainly carbonate of lime, with a little 

 suli^hate of lime and chloride of sodium. The specimens of water 

 drawn from the lead pipes were entirely free from even traces of that 

 metal. The white powder referred to was found to be oxide of tin, 

 with a mere trace of iron. I accordingly reported that I did not think 

 any harm would arise from the use of the water, — as the water was a 

 pure one, and free from lead, — and that oxide of tin was not regarded 

 as injurious. 



