I 



of Mineral Substances. 277 



As no other ingredient Avas to be detected, it appears that the 



78 grains of ore contained seven of oxygen. 



If, therefore, we exclude the metaUic copper, which is to be 



regarded as mixed and not chemically combined with the ore. 



the composition of 100 parts of the octoiidral red copper ore of 



Siberia is as follows : 



Copper . . . . . 91 

 Oxygen ..... 9 



100 



Analysis of the fibrous Blue Copper Ore of Siberia. 



This ore occurs in the Turjin mines of the Ural mountains, 

 generally in globular concretions of dark blue crystals, which 

 appear to be somewhat oblique four and six-sided prisms. The 

 specimen selected for examination was coarsely powdered, 

 and washed to separate some adhering earthy particles. 



A. 100 grains ignited in a covered crucible, acquired a 

 black lustre, and lost 30 grains. 



B. Nitric acid dissolved the ore with effervescence, forming 

 a transparent blue solution, which was not affected by the ad- 

 dition of acetate of baryta, acetate of lead, nor nitrate of 

 .silver. 



C. 100 grains of the ore dissolved completely in muriatic 

 acid, forming a dark green solution, which became bluish 

 when diluted. On supersaturation with caustic ammonia, the 

 precipitate first formed was entirely redissolved ; the ammoni- 

 acal solution was then supersaturated by sulphuric acid, and a 

 plate of iron immersed, which caused the separation of 56 

 grains of copper. 



D. 100 grains of the ore were put into a counterpoised pnial, 

 containing a sufficient quantity of sulphuric acid diluted with 

 four parts of water, and were gradually dissolved without the 

 aid of heat. The evolution of carbonic aciii produced a loss 

 of weight equal to 24 grains : the solution precipitated by zinc 

 gave 56 grains of copper. 



E. 100 grains of the ore heated in a small glass retort con- 

 VoL. XI. U 



