25.G Analysis of the Copper Ore of Franconia. 



consisted of oxide of copper, the weight of which was equi- 

 valent to 15.95 of the metal. 



(D.) The insoluble portion (A.) was carefully dried, and 

 weighed 7.50 grains ; exposed to heat it took fire and burnt 

 with a blue flame, losing in this manner 7.40 grains, equiva- 

 lent to sulphur 7.40. 



(E.) The portion remaining after the combustion of the 

 sulphur was silex ; it weighed as nearly as could be ascer- 

 tained 0.05 grains. 



(F.) To the liquor separated by filtration from the pre- 

 cipitate (C), a solution of chloride of Barium (mur. barytes) 

 was added ; sulphate of Baryta was precipitated ; it was well 

 washed, and dried, and its weight was equivalent to 12.50 

 grains of sulphur. 



Hence, fifty grains of the Franconia ore contain by analysis, 



Copper, (C) 

 Iron, (B) 

 Sulphur, (D & 

 Silex, 



Loss 



50.00 100.00 



If the silex which exists in very small quantity be neglected 

 as an accidental admixture, the remaining substances will ex- 

 ist nearly in such proportions as constitute one atom of sul- 

 phuret of copper, and one atom of the sesquisulphuret of 

 iron. Such an ore would consist of one atom ofy copper, 



