258 THE PRESIDENT S ADDRESS. 



For 21 years, from 1838 to 1859, there was a considerable 

 demand for iron and copper pyrites from the Cornish mines, for 

 the purpose of extracting from it sulphur in the manufacture of 

 sulphuric acid. It is from the residue of this kind of ore, after 

 it has been burnt, and the sulphur extracted from it, that the 

 copper, tin, and silver remaining in it is extracted by means of 

 the "wet process." The value of the produce from this process 

 has already brought into existence about 24 companies in 

 different parts of England, 3 of which have been established in 

 Cornwall and Devon. 



To shew the extent to which this process has been adopted, it 

 may be interesting to give a few particulars. 



In the year 1875, 365,368 tons of this cinder, or residue, which 

 is known as "burnt ore," has been treated in the United 

 Kingdom by the "wet process," and the quantity of copper 

 extracted in the year 1875 alone from cupreous pyrites, has been 

 calculated to be not less than 14,000 tons, or rather more than 

 three times the aggregate amount of cojjper prodixced by the 

 mines of the United Kingdom ; and, it must be remembered, 

 that this 365,368 tons of burnt ore represents only about 70 per 

 cent, of the weight of raw ore consumed each year. The annual 

 consumption of these ores in a raw state in the United Kingdom, 

 amounts in round numbers to 500,000 tons, which after being 

 employed for the production of sulphur, in the manufacture of 

 sulphuric acid,*' becomes a cinder or residue, called "burnt 

 ore." 



Between 1838f and 1859 (as I have said) the mines of Cornwall, 

 and of "Wicklow, in Ireland, supplied nearly the whole of the 

 pyrites which was used in this country to produce sulphuric 

 acid. Since the latter year, the pyrites from Spain and Portugal 

 has got possession of the market, in consequence, not only of 

 the svipx^ly from those countries being more regular and abundant 

 than from Cornwall, but their ores are besides more uniform in 

 composition, seldom varying one per cent, in the amount of 

 copper they contain ; whereas the ores from Cornwall were too 

 irregular in their supply to meet such a large demand. Although 



* Liebigr remarked, that the commercial prosperity of a country may be 

 judged of with much accuracy from its annual consumption of sulphuric acid. 

 t Before 1838 it came chiefly from Sicily. 



