BO 
Copper . 
ten or twelve miles between Liverpool and Warrington^ 
made of the slag of copper works. 
7. The theory of cleansing copper from its impure 
mixtures, is, that it is less easily oxydable than iron, zinc, 
antimony or the other semi- metals. Sometimes iron is 
added to promote the separation of the sulphur : some- 
times lead to promote the oxydation of the more oxydable 
metals. I cannot say in what proportions, or under what 
circumstances, because this must depend on the mixture 
to be determined by the previous analysis of the ore. In- 
deed, I distinctly remember, endeavouring to ascertain 
the mixtures and the circumstances, but without effect. 
It either was, or was pretended to be a great secret. Eve- 
ry manufactory in England, is a repository of secrets. I 
suspect the process would be aided by manganese. 
8. I am under no hesitation in saying, that the inter- 
mixture of charcoal dust, or coak dust, with the ore both 
in the previous roasting, and in the furnace, and making a 
thin coating at the bottom of the hearth and basin, of the 
same material, would greatly promote the fusion and puri- 
fication of the matt. T oward the last stage of the process 
of refining, when the oxydable metals are to be oxyded, 
there would be no difficulty, if need required, to intro- 
duce a current of air over the surface of the melted metal, 
as it appears to me. But I have not skill in the subject 
to do more than suggest. 
Copper is an article so necessary to us at present for 
sheathing ships, for making distilling vessels, for vessels 
used for culinary purposes, for plated ware, for coin, &c. 
&c. that I hardly know any manufacture of such impor- 
tance, after that of iron : and yet we have no smelting 
work for copper, or any copper mine worked in the Unit- 
ed States. Nor shall we have, till steam engines to draw 
off the water and to raise the ore, become common. I 
would gladly undertake the article mining , and perhaps I 
