copper. 265 



globule. Its constituent parts are, peroxide of copper 68*13, 

 phosphoric acid 30-95. Klaprolh. Phosphate of copper is a 

 rare mineral, and is found principally at Virneberg, on the Rhine, 

 where it occurs along with quartz, calcedony, red copper ore, and 

 malachite, in greywacke. 



There are some other species, but they are of little importance 

 to the metallurgist, being never worked exclusively as ores of 

 copper. The sulphurets are the ores from which the metal is 

 usually extracted. The method of reducing them consists essen- 

 tially in driving off the sulphur, oxidizing the iron, and converting 

 it into silicate, while the metal is separated in a tolerably pure 

 state. In Cornwall the ore is broken into small pieces, and 

 roasted in a reverberatory furnace for about twelve hours, occa- 

 sionally stirring it, so as to expose new surfaces to the air. It is 

 then put into a small furnace, and brought to a state of fusion, 

 sometimes mixed with a little lime, to increase the fusibility. As 

 the impurities collect at the top, they are raked out, and put into 

 oblong moulds, in which they are allowed to cool : they then form 

 a hard mass, which is used in building. The fused copper is 

 drawn out through a hole in the lower part of the furnace into an 

 adjoining pot filled with water ; fresh quantities of roasted ore are 

 then put in, and the process is in this way carried on for a consi- 

 derable time. By this process the metal is reduced to the gra- 

 nular state ; it is still, however, impure, being mixed with sulphur 

 and arsenic. To free it from these the metal is repeatedly sub- 

 jected to the heat of a reverberatory furnace, and each time put 

 into the well. During these processes, the slag (silicate of iron) 

 collects on the surface of the fused metal, but as this contains a 

 considerable quantity of copper, it is kept, and mixed with the 

 fresh ore, previous to its being put into the furnace. The copper, 

 after this, is kept at a low red heat for two days, and is then 

 repeatedly fused, and cast into moulds about fourteen inches in 

 length. It is lastly put into the refining furnace, with a little char- 

 coal, in which it is again fused. If, after this, it bear the hammer, 

 it is fit for sale. 



Pure copper has a yellowish-red colour, and considerable lustre. 

 It has a disagreeable styptic taste, and emits a peculiar foetid odour 



