ZINC. 



of well-known purposes. Its oxides are used in 

 the manufactures of glass, and the glazings of 

 earthenware; also as pigments. Preparations 

 of lead are also used as external applications in 

 diseases. The alloys of lead with tin form solder, 

 and other alloys are employed in various arts. 



ZINC. 



This metal is chiefly procured from calamine, 

 which is a hydrated oxide of zinc ; and from blende, 

 a sulphuret of zinc. 



Zinc is a whitish metal of the colour of tin. It 

 is slightly malleable when cold ; but heated to 

 between 200 and 300 it is very malleable, and 

 has been manufactured into nails, drawn into wire, 

 and made into sheets. 



It is often known among workmen by the name 

 of Spelter. It is easily fused, and is the most in- 

 flammable of the metals; thin leaves of it will take 

 flre with the flame of a taper. 



It is scarcely oxidized in the air at common 

 temperatures, but is rapidly converted into oxide 

 when kept melted in an open vessel. Its surface 

 then becomes covered with a grey pellicle, which 

 is oxide of zinc. When zinc is made red hot in an 

 open vessel, it takes fire and burns with a brilliant 

 flame, sending off white flakes of oxide. These 

 have been calledjlowers of zinc. 



Zinc decomposes water very slowly when cold ; 

 but with great rapidity when the vapour of water 

 is brought into contact with it ignited. 



Zinc dissolves very readily in diluted sulphuric 

 acid; forming thus sulphate of zinc, or white vitriol. 

 During this solution, a great quantity of hydrogen 



