MINERALOGY. 



311 



lightest of the ductile Metals, it is harder and more 

 tenacious than L.^ad, and is very fusible 



Tin is used as an alloy with various other Metals, it is 

 formed into exceedingly thin plates or leaves, under the 

 name of Tin-foil, and this combined with Mercury, is used 

 for silvering the b:icks of Mirrors and Looking Glasses* 

 Tin is also used for the purpose of lining Copper vessels for 

 domestic purposes, this is done by heating the vessels, 

 having previously scraped the inside with an Iron instrument, 

 and then rubbing the internal surface with Sal Ammoniac, 

 when the vessel is quite hot a small quantity of Pitch or 

 Resin, is thrown in and suffered to spread entirely over the 

 internal surface, which completely prevents the Copper from 

 oxydlzing, as Tin will not combine with oxyde of Copper ; 

 when these preparatory measures are taken, a piece of pure 

 tin is applied all over the inside of the hot Copper vessel, 

 which instantly assumes a bright silvery whiteness, and 

 prevents any unpleasant effects in using Tinned Copper 

 vessels for culinary purposes. 



Most of the Saucepans &c., used for kitchen purposes, 

 under the name of Tin ware, are formed of thin plates of 

 Iron, coated with Tin, these are first scoured, and then 

 thrown into a solution of sulphuric acid^ which destroys all 

 the rust or oxyde, and renders the surface perfectly clear; 

 the plates are then dipped into melted Tin, the surface of 

 which is covered with oil or fat to keep it from the action of 

 the air, by these means the Iron coming in contact with the 

 pure melted Tin, it comes cut conjpletely coated ; the Tin 

 frequently penctra Wng the substance of the Iron. 



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