OF SUMATRA. ig 



with a force destructive of every vulnerable sub- 

 stance within the sphere of its action. I have been 

 informed, that the metal has been eliqnated at 

 Mad? as lately, and found to contain very little ap- 

 pearance of any other but of gold. The usual sol- 

 vents, aquafortis, aqua regia, and spirit of salts, 

 readily dissolve the Sumatran copper. A deep green 

 solution is produced, in a very short time, by the 

 action of the weaker acids on the rough ore. The 

 above method of smelting will separate all coafse, 

 mineral, and heterogeneous substances from the 

 metal, but will still leave it strongly impregnated 

 with its peculiar mineral earth. The detaching of 

 this mineral earth is the most difficult and expensive 

 operation attending the refinement and purification 

 of copper ; it being frequently necessary to add 

 a proportion of another metal to effect it. This 

 consideration will, probably, prevent a private 

 company from applying for public permission to 

 work these mines; and, therefore, they must remain 

 in their present state, unless the East India Company 

 will order the experiment to be made, from the reports 

 and opinions of such as may be qualified to give them 

 on so interesting a subject. By submitting this short 

 account to the gentlemen of our Society, whose useful 

 researches, will, I hope, produce permanent national 

 benefit, by advancing the knowledge of nature, of sci- 

 ence, and of literature, opinions properly weighed, 

 will be diffused among the public, of the advantages 

 that mav result from an establishment for working 

 copper-mines on the west coast of Sumatra, 



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