1 82 1 .] of the Atoms of Copper ^ Zinc, Iron, Manganese, S^x, 245 



The existence of these three salts, similar to the oxalate, 

 binoxalate, and quadroxalate of potash, and in some respects 

 similar to the triple oxalates of potash, soda, ammonia, and 

 copper, discovered and analyzed by Vogel, of Bareuth, leave 

 little doubt in my mind that the true atomic weight of copper 

 is 8. 



(4.) The common green permuriate of copper is a compound 

 of one atom peroxide of copper and two atoms of muriatic acid; 

 for when 10 grs. of peroxide of copper are dissolved in muriatic 

 acid, and the liquid evaporated to dryness, a brownish yellow 

 coloured mass remains, which weighs exactly 17 grs. It is, 

 therefore, a perchloride of copper composed of 



1 atom copper = 8 



2 atoms chlorine = 9 



17 



There exists likewise a protochloride of copper, described by 

 Boyle under the name of rosin of copper, and since particularly 

 described by Proust,. Chenevix, and by Dr. Davy who an- 

 alyzed it, and showed it to be a compound of 



1 atom copper = 8*0 



1 atom chlorine = 4*5 



m 



(5.) There is reason to conclude from the experiments of Ber- 

 •zelius, that sulphuret of copper is a compound of 



Copper 8 



Sulphur. » jii|4iii ;/. 2 iridi- dd iii>v 31 



10 



So that an integrant particle of it weighs precisely as much as 

 the peroxide of copper. Now it is well known that an atom of 

 sulphur weighs exactly twice as much as an atom of oxygen. 

 Hence the sulphuret must be a compound of one atom sulphur 

 4- one atom copper ; and if so, an atom of copper must weigh 8. 



I shall now proceed to show that the composition of blue 

 vitriol is exactly as I have stated in a preceding part of this 

 essay ; namely, 



2 atoms sulphuric acid = 10*00 



1 atom peroxide of copper = 10*00 



10 atoms water = 1 1-25 



31-25 

 The reader, by turning to a former paper of mine {Annals of 



