400 Foreign and Miscellaneous Intelligence. 



numerous white points and ramifications of metallic silver. It fused 

 also in open and closed vessels ; and, when ignited in a retort, tinged 

 the glass with which it was in contact of a yellowish colour : in 

 the open tube it deposited a small quantity of white sublimate, part of 

 which was volatilized by directing the flame upon it, the rest contract- 

 ing into small globules. 



It was found to dissolve in nitric acid, particularly when heated, 

 but much less in nitro-muriatic acid, being soon covered by a crust 

 of chloride of silver. If the solution in nitric acid was suffered to 

 cool, small brilliant crystals were deposited, which consisted of the 

 oxides of tellurium and silver, but in a different proportion from what 

 they are in tellurium-silver, for, a short time after their formation, 

 crystallized nitrate of silver was deposited. 



M. Rose submitted the mineral to the following analysis : It was 

 dissolved in nitric acid, and after the silver had been precipitated by 

 muriatic acid, the solution was filtered and evaporated ; sufficient 

 quantity of muriatic acid was now added until all nitric acid was de- 

 composed, and no smell of chlorine could be perceived. The liquid 

 was then diluted with water and heated, and on the addition of mu- 

 riatic acid and sulphite of ammonia, a black precipitate was obtained, 

 which consisted of metallic tellurium. The remaining fluid, being 

 filtered, was again submitted to the action of sulphite of ammonia and 

 muriatic acid, and this was repeated as long as a precipitate formed. 

 A current of chlorine gas was then passed through the filtered liquid, 

 in order to oxidize completely the small quantity of iron contained in 

 it, and this was afterwards precipitated by ammonia. 



By this process M. Rose obtained from 2.833 gramm. of the mine- 

 ral, 2.348 gr. of chloride of silver, which contain 1.769 gr. of silver, 

 1.047 gr. of tellurium, and .010 gr. of oxide of iron. By a second 

 analysis, 2.678 gr. of the mineral were found to consist of 1.669 of 

 silver, 0.988 of tellurium, and .050 of iron. 



According to the first analysis, tellurium-silver consists of 

 Silver . . . 62.42 

 Tellurium . . 36.96 



Iron , . 0.24 



According to the second, of 



Silver . 62.32 



Tellurium . 36.89 



Iron . . . 0.50 



And if tellurium-silver be considered as a compound of one atom of 

 silver = 62.63, and one of tellurium = 37.37, the above results are 

 nearly confirmed*. 



The other mineral, tellurium-lead, is, like the former, not crystal- 

 lized, but cleavable in three directions ; the planes of cleavage are 

 not quite even, but seem to be at right angles to one another. Its 

 colour is tin white, almost like antimony, but a little more yellow ; 



* According to Berzelius, the atomic weight of silver is 1351,005, and that of 

 tellurium 806,45, osygeu being 100. 



