478 On the Iron-pyrites Mines of Andalucia. | Oct., 
passing off as sulphurous acid, the fumes of which destroy the sur- 
rounding vegetation, and corrode the iron used in the neighbouring 
buildings. It is only of late years that the ingredient just mentioned 
has been turned to account; but the commercial success of using 
the mineral as a source of sulphur has been so great, that it is now 
looked upon more as a sulphur than a copper ore. Up to 1840 
Sicilian sulphur was chiefly used in the manufacture of sulphuric 
acid, but about that time the King of Naples granted a monopoly 
of the export of Sicilian sulphur to Messrs. Taix and Co., of 
Marseilles, and the price of the commodity was in consequence 
doubled. The manufacturers were thus obliged to cast about for 
other and cheaper sources of sulphur, and many adopted the use of 
iron-pyrites, procuring them at first from Wicklow and Cornwall, 
and since 1856 from Spain. This mineral has now almost super- 
seded sulphur, only a small quantity of acid, which is required for 
chemical purposes to be of great purity, being manufactured from 
the latter. Details respecting the introduction of pyrites into this 
country and the process of manufacture will be found in ‘A History 
of the Trade and Manufactures of the Tyne, the Wear, and the 
Tees, * p. 159. 
The other ingredients of the ore are also turned to account by 
the manufacturers of the North of England. The copper is extracted 
from the residuum both by cementation and smelting, and in one 
manufactory at least the remaining oxide of iron was smelted as an 
iron ore; it would seem likely, however, that with regard to the 
last process the remnant of sulphur and arsenic would tell very 
much against the quality of the metal obtained. 
The above sketch deals mainly with facts; for though I would 
gladly have attempted some explanation of the method of formation 
of these strange mineral masses, I felt that with the scanty data at 
my disposal any such attempt would have been rash theorizing. 
My own visit was too hurried, and my time too much taken up 
with other matters, to leave leisure for questions of purely scientific 
interest ; and the works I have had access to treat the subject more 
from a mining than a geological point of view. 
* London: E. & F. N. Spon, 1863. 
