ANALYSIS OF A NEW SPECIES OF LEAD-ORE. 257 



Sulphuret of lead, - 57.269 

 Sulphuret of copper, ^- 40.850 

 Sulphuret of iron, - 2.190 



100.309 



That this ore is not a mere mechanical mixture 

 of these sulphurets, I conceive proved by this cir- 

 cumstance. I attempted in vain to separate the 

 sulphuret of copper from the sulphuret of lead, 

 by washing the powdered ore upon an inclined 

 plane. Yet the specific gravity of these two sul- 

 phurets, is so different, that their mechanical se- 

 paration ought to be easy, unless they be chemi- 

 cally combined. Now, it deserves attention, that 

 the ore, (neglecting the small quantity of sulphu- 

 ret of iron, which is probably accidental,) consists 

 of one integrant particle of sulphuret of lead, 

 combined with two integrant particles of sulphu- 

 ret of copper. Hence I am disposed to consider 

 this ore as constituting a new species of lead-ore, — 

 a species, however, of comparatively little value 

 in a metaiiurgic point of view ; because lead and 

 copper are mutually injurious to each other, and 

 it would be difficult to devise cheap methods ot 

 separating them. 



As this ore has only been met with in apothe- 

 caries shops, and as we are ignorant of any mine 

 of it actually existing, it may be supposed per- 

 haps to be an artificial combination. From the ap- 

 pearance of the specimen which I examined, no 



VOL. I. R 



