C 3° 3 
IV. Description of a triple Sulphur et, of Lead , Antimony , and 
Copper, from Cornwall ; with some Observations upon the various 
Modes of Attraction which influence the Formation of mineral 
Substances, and upon the different Kinds of Sulphur et of Copper. 
By the Count de Bournon, F. R. S. and L. S. 
Read December 22, 1803. 
SULPHURET OF LEAD, ANTIMONY, AND COPPER. 
This substance, which has hitherto been found only in Corn- 
wall, has been many years known in England. Most of the 
collections of minerals in London contain specimens of it, in 
which its peculiar characters are more or less distinctly seen ; 
nevertheless, either the scarcity of this mineral (the mine* in 
in which it is found having never been regularly worked) has 
been an obstacle to its being more known in Europe, or the 
nature of its external characters, which do not allow it to be 
classed with any of the mineral substances already described, 
has prevented mineralogists from giving it a place in their works ; 
for, it is very certain that none of them, not even those who have 
lately written, have taken any notice of it. 
In the country where this mineral is produced, it has been 
generally considered as an antimonial ore ; but no observation, 
at least none that has ever come to our knowledge, had yet de- 
termined, whether it was an ore of antimony, properly so called, 
* Huel Boys, in the northern part of Cornwall . 
