jiRSENIATEP COPPER. 251 



analyus had not been poffible, certainly no naturallfl would 

 have hefitated to feparate (hem from each other, according to 

 the exterior characters fliown by each of Ihem, 



Why therefore, becaufe thefe fubftances all belong to the 

 combination of the fame acid with the fame metal, (hould 

 there not be found feveral fpecies among them? This, I be- 

 lieve, is a fad which occurs much more frequently tlian has 

 been hitherto fuppofed. Do not all the metals (how various 

 inftances of ftriking difFerences in the oxides, in confequence 

 <of that which exifts in the combination of oxigen with them ? 

 The octahedral attractive oxided iron, that which is rhomboidal. Variations in 



(hat not attraflive, are not all thefe fo many fpecies ? In a me- '["^ Jliecies of 



-' '^ Uie fame chc- 



moir which was inferted in the 75th number of ihe Journal des micalcombina- 



Mines, 1 have endeavoured to (how that the otlahedral fill- ^'°"' 

 phurated iron, and that in cubes, formed two very diftind 

 fpecies, and I do not believe that thefe are the only ones which 

 exiR in it. How many fpecies are offered by fulphurated cop- 

 per ! I am myfelf acquainted with fix, all perfe61Iy diflin6t and 

 charaderized, which I have long intended to give the defcrip- 

 tion of, but my occupations and want of time have not yet 

 permitted me. Finally, have not you yourfelf been compelled 

 to form a particular fpecies of carbonated lime, of the arra- 

 gonite, from the difF^rence alone, which exifts in its exterior 

 fpecific charaders, although chemiftry can only find carbonic 

 acid and lime in it ? 



One reafoii which may be alledged againft the divifion of 

 arfeniated copper into fpecies, is that the combination of cop- 

 per with the arfenical acid being already a fpecies in the genus 

 of ores of copper, it would be making fpecies of a fpecies: 

 and this objedion, which at the firft blufh appears well founded, 

 would bear equally againfl: the various oxides, fulphurets, &c. 

 But this difficulty feems to me lo be moie (pecious than folid: 

 it takes its rife from the iinpoflibility in which we ftill are of 

 afcertaining every thing conneded with the different caufes 

 which may produce a variation of the fpecies. Without doubt, 

 in this inftance, for example, it is not the fiinple combination 

 of the arfenical acid with the copper which forms the fpecies, 

 but the particular combination of this acid with the metal. 

 Thus it is not the limple combination of oxigen, hidrogen, 

 carbon, azote, &c. which conftitutes the particular fpecies of 

 animal, but the manner of the combination itfelf. 



The 



