July, 1846.] Proceedings of the Asiatic Society. Ixv 



2. The pure ore is in the usual pseudo cubic and cubico -laminar masses and 

 fragments. By the common goniometer the angles of the best fragments, perfectly 

 bright and pure, which I could pick out, were 88° on 92° and the faces were 

 evidently slightly curved. 



The specific gravity of a good crystal, water-worn, but with all impurity care- 

 fully washed from it, was 745 



Of a bright mass from the lumps, which however might retain a little air. . 7.51 



Mean, 7.485 

 Thomson gives 7.53 to 7.65 for galena, but according to Vauquelin it may 

 vary from 7.10 to 7.60, and thus specific gravity is evidently an uncertain cha- 

 racter, especially where, as in this ore, antimony and silica and silicate of iron form 

 considerable proportions. 



3. Before the blowpipe it does not decrepitate and fly, but melts and disen- 

 gages bubbles ; gives a bright but dark-coloured steel-grey metallic bead with little 

 bubbles on its surface ; smokes when roasting, and the charcoal has the bluish gray 

 deposit of the antimonial ores. By continuing the reduction it becomes a bright 

 tin-white and highly malleable bead, giving then the dull yellow powder of oxide of 

 lead on the charcoal as the bead diminishes. The closest and often repeated inves- 

 tigations could discover no trace of silver or arsenic. Iron, bismuth, lead, antimony, 

 sulphur and silica were the only constituents of the purest ore ; the bismuth also in 

 very small quantities. 



4. The results of several analyses made on various proportions of the purer and 

 impure portions, and in large averages of 1000 grains, that nothing of value might 

 be overlooked, gave always the same results as to constituents, and the absence of 

 silver ; with now and then a trace of copper from the copper pyrites already no- 

 ticed as occurring in the matrix. 



The picked and purest ore contains per cent.-— 



Water (Hygrometric), 2.50 



Sulphuret of Lead (Galena), (giving Metallic Lead,. 47.02) 54.50 



Sulphuret of Antimony, (giving Metallic Antimony, 4.7) 17.00 



Oxide of Iron, 4.00 -1 



Silicate of Iron, 21.50 J ' '" 25,5 ° 



Bismuth trace, 0.00 



9950 

 Loss, 0.50 



100.00 



There can be no question that this vein should be followed to see what changes 

 of ores, if any, take place. It is almost positively mischievous to publish the exa- 



