256 



METALS. 



LEAD. 



637. DESCRIPTION. Lead is a bluish 

 scription, ores grey metal, extremely malleable, and read- 

 and solvents? ^ tarnished in the air. It is heavier than 

 any other of the metals mentioned in this work, except 

 mercury, gold, and platinum. Nitric acid is its proper 

 solvent, forming with it, a colorless solution. The 

 principal ore of this metal, is galena, or sulphuret of 

 lead. Lead is also found as carbonate, sulphate, and 

 phosphate of lead. 



How is lead 638. PRODUCTION. Lead is obtained 



obtained? from the sulphuret, by heating it with 

 iron, to remove the sulphur. A mixture of metallic 

 lead and sulphuret of iron are 

 thus produced, from which 

 the lead separates by its 

 greater specific gravity. If 

 the oxide of lead could be 

 readily obtained, the reduc- 

 tion by charcoal would be 

 as applicable here, as in the case of other metals. 



639. A SECOND METHOD. Another 

 method, is to heat the sulphuret with a 

 portion of sulphate. The sulphate has a large supply 

 of oxygen, while the sulphuret is destitute of this ele- 

 ment. The two may be mixed in such proportions 

 that they will together contain just enough oxygen to 

 carry off all the sulphur, as sulphurous acid. This 

 result having been accomplished by heat, the pure 

 metal of both remains behind. As a preparation for 



JSxplain an- 

 other method. 



