22$ sulfhuret op lead, copper, and antimony. 



En t dellion. 



Part I. 



IndelHon not When in the moDtli of December, 1803, I presented t« 



IntS»ony, re ° f t,,e R °- va1 St %ty a P«P«" ou the tl-i P le sulplu.ret of lead, 



copper, and antimony, considered at that time as a simple 



ore of antimony, I thought it the more necessary, to fix the 



externa! characters of this substance, as Mr. Hatchett had 



just shown by his analysis of it, that, so far from being a 



but ample simple ore of antimony, it was an ore composed of three 



sulphurot. sulphurets, those of lead, copper, and antimony, in which 



the latter was not even the principal metal. 

 The character It was not in my power at that time however, to establish 

 liza'iions^ouki ^ ie character °f tne crystallizations of this triple sulphuret 

 n«t at first be with all the precision, that the case required, and that I 



fwi^if j cOutd have wished. This substance was then extremely 



tabhshed. •* 



scarce, as it is even now. The crystals I was able to pro- 

 cure being small, and with numerous sides, most of which 

 'were irregular, did not allow me to depend sufficiently on 

 the measures I was able to take, to venture to lis in a pe~ 



P.-imiiive crys- remptory manner the dimensions of its primitive crystal. 



**** All that I could then determine positively was, that this 



crystal was a rectangular tetraedral prism with square bases, 

 but not a cube. In consequence [ satisfied myself with 

 establishing this truth, without setiling the dimensions of 

 the crystal. It necessarily followed, that the measures givea 

 as those of the angles of incidence between the primary 

 and secondary faces, as they could not be the result of a 

 calculation (he bate of which was not determined, must 

 have been merely taken with the graphomeier, and conse- 

 quently to be considered as approximations only ;-yet as ap- 

 proximations having all the accuracy the instrument would 

 admit, and the inaccuracy of which could not amount to one 

 degree. 



Desirous from that period of giving a more complete ac- 

 count of this rare and interesting substance, and ascertain- 

 ing at the same time in a more positive manner the form of 

 its primitive crystal, I omitted no opportunity offered me 

 of continuing to study it. For auch opportunities, as I 



could 



