72 



humid analysis. Eefmring to Swansea as the great emporium for 

 copper ores in this country, he described the following operations for 

 the reduction of the metal, as there practised : — 



]st. — Calcination of the ore to expel the greater amount of sulphur. 

 2ud. — Melting the ore obtained from No. 1 to obtain a coarse 

 metal, and to which a quantity of unroasted ore is added, rich in 

 copper. 



3rd. — Calcination from the product No. 9. 



4th.— Melting the calcined coarse metal along with minerals of the 

 fourth class, in order to produce what is termed white metal. 



5th. — Melting this last product with roasted minerals rich in copper, 

 in order to produce blue metal. 



6th.— Eemelting the slags obtained from the various former opera- 

 tions. 



7th. — Roasting the metal obtained from No. 5. 

 8th. — Roasting again to obtain a regulus or crude copper. 

 9th. — Preparation of crude copper by roasting and fusing the white 

 metal and regulus. 



10th. — Refining the crude copper, and producing the pure malleable 

 metal. 



Having gone through these processes minutely, and explained that 

 for obtaining the Copper in absolute purity for scientific purposes, he 

 described the various salts, chemical compounds, and alloys of the 

 metal. Brass and bronze being the most important of these alloys, 

 he enumerated their varieties. Those of brass, he described as being 

 five in number — 1st, that which is used for turning, composed of from 

 30 to 35 per cent, of zinc, from 60 to 65 per cent, of copper, about 2 

 per cent, of lead, and a trace of tin. 2d, brass for gilding, containing 

 64 per cent, of copper, 33 per cent, of zinc, 2.5 per cent, of lead, and 

 a trace of tin. 3d, brass wire ; 66| per cent, of coppei', 33.1 of zinc, 

 lead, 0.5. 4th, for hammering; copper 70 per cent, and zinc 30 per 

 cent. 5th, for castings; copper 01. 7, zinc 5, lead 2.3 per cent., and 

 tin 1 per cent. 



The proportion of zinc added generally varies from 30 to 38 per cent. 

 When an alloy of great tenacity is required, there should only be about 

 25 per cent, added ; whilst on the other baud, when an alloy of little 

 resistance is wanted, 50 per cent, of zinc may be used. 



Copper also united with nickel, forming the well known alloy called 

 German silver, as well as the pakfoug of the Chinese. That which is 

 employed in Europe for the manufacture of forks and spoons, is com- 

 posed of 50 per cent, of copper, 25 per cent, of Nickel, and 25 per cent, 

 of zinc. The Chinese pakfong varies to a slight extent from the German 



