Ill 



TIN. 



Tin is a metal of a colour approaching to that of 

 silver, but somewhat duller. It is extremely malle- 

 able. When hammered into leaves it constitutes 

 tin-foil. It is not, however, very ductile. It is 

 nearly as soft as lead, and may be easily bent, and 

 then emits a crackling noise, which is peculiar to it. 



Tin fuses more easily than any other metal : 

 when it has been kept some time in a state of 

 fusion, with access of air, its surface becomes 

 wrinkled and covered with a grey pellicle, which is 

 the Jirst, or grey oxide of tin. This oxide when 

 mixed with melted glass forms white enamel. 



The grey oxide, when exposed to a greater 

 degree of heat, takes fire, acquires more oxygen, and 

 -becomes of a pure white ; the white oxide of tin. 



Tin is not oxidized in the air at the common 

 temperature -, on account of which property, it is 

 used for covering iron plates, to prevent their 

 rusting. 



Tin dissolves in the muriatic acid, forming muri- 

 ate of tin, much used by dyers. 



With nitric acid it forms nitrate of tin. 



Tin united with sulphur forms the aurum mus~ 

 ium. Alloyed with lead, it forms plumber's solder. 



The best pewter is composed of tin alloyed with 

 antimony, copper, and bismuth. 



Tin is not found native, and its ores are not much 

 distributed. The richest mines are in Cornwall. 



LEAD. 



This metal is never found in a native state. The 

 ore from which it is chiefly procured is galena, 

 which is lead united to sulphur, or a sulphuret 

 of lead. 



