OF ARTS AND SCIENCES. 221 



action of distilled water, Thames water, water from artesian wells in 

 London, and to water highly charged with organic matter ; and in no 

 case, where these waters have been exposed to the usual reagents for 

 detecting the presence of tin or lead, has the slightest quantity of these 

 metals been detected." 



Field * states that tin does not oxidize at ordinary temperatures in 

 the air, and but very slightly in watei', retaining its metallic lustre for 

 a long time ; and, again, it is not sensibly affected by the combined 

 presence of air and moisture. 



This extensive corrosion of the metal seems, therefore, to be a 

 hitherto unrecorded circumstance, tin being generally regarded as the 

 least liable to change of all our common metals. The metal, as will be 

 seen, is entirely eaten through in some places. 



* Watts' Diet., Vol. V. pp. 803-4. 



