ORES OF LEAD. 



145 



of copper to 57£ parts of tin. The brothers Keller, celebrated for 

 their statue castings, used a metal consisting of 91 4 per cent, of cop- 

 per, 5 53 of zinc, 17 of tin, and 137 of lead. An equestrian statue of 

 Louis XIV., 21 feet high, and weighing 53,263 French pounds, was 

 cast by them in 1699, at a single jet. 



An alloy of copper 90, and aluminum 10, is sometimes used in place 

 of bronze. 



LEAD. 



Lead occurs rarely native ; generally in combination with 

 sulphur ; also rarely with arsenic, tellurium, selenium, and 

 in the condition of sulphate, carbonate, phosphate and 

 arsenate, chromate and molybdate. 



The ores of lead vary in specific gravity from 5'5-8'2. 

 They are soft, the hardness of the species with metallic lus- 

 tre not exceeding 3, and others not over 4. They are easily 

 fusible before the blowpipe (excepting plumbo-resinite); and 

 with soda on charcoal (and often alone), malleable lead may 

 be obtained. The lead often passes olf in yellow fumes, 

 when the mineral is heated on charcoal in the outer flame, 

 or it covers the charcoal with a yellow coating. 



Native Lead. 



A rare mineral, occurring in thin laminae or globules, 

 G. =11 "35. Said to have been seen in the lava of Madeira ; 

 at Alston in Cumberland with galena ; in the County of 

 Kerry, Ireland ; in an argillaceous rock at Carthagena ; at 

 Camp Creek, Montana. 



Galenite. — Galena. Lead Sulphide. 

 Isometric. Cleavage cubic, eminent, and very easily ob- 

 tained. Also coarse or fine granular ; rarely fibrous. 



^ 



1. 





f<\ H ^ 



\n 



H 





C 



_..-■ 



--J 



X" 



Color and streak lead- gray. Lustre shining metallic. 

 Fragile. H.=2-5. G. = 7-25-7-7. 



