52,8 Dr. fordy,ce and Mr. alchorne’s 
The firft ore we mean to confider is called gold pyrites. 
Pyrites is an ore of iron, containing fometimes copper, 
fometimes arfenic, fometimes other metals; generally, if 
not always, combined with fulphur. 
This ore, from its yellow colour, has at firft fight been 
often taken for an ore of gold. It is the moft common of 
all ores, and on examination is very feldom found to con- 
tain gold. Specimens, however, have been found from 
which gold has been procured; and, particularly, there 
have been found in Fatchobuigna near Zalatna, in Tran- 
fylvania, mafles which contain a large proportion of this 
metal. Sometimes the gold is in its metallic form, and 
vifible to the naked eye; fometimes it is not: and in 
thefe cafes the ore has been thought to contain the gold 
united firft with iron, and that compound united with, 
fulphur. 
Dr, fordyce obferves on this propofition, that it has 
not as yet been proved, that a compound metal can be 
combined with fulphur. If two metals are foluble in 
fulphur, and each be feparately combined with it, the 
two compounds may be diffufed through one another, as 
is the cafe with the compounds of fulphur and iron, and 
fulphur and copper; which may be diffufed through one 
another : but if we have a compound of two metals, of 
which one is foluble in fulphur, and the other is not, if 
we 
