24 Berzelins gu a new Mineral Bodtj, [Jan. 



after being well washed, dried, and fused, weighed 50-7 parts^ 

 equivalent to 38-'J3 parts of metaUic silver. On the filter 

 remained a mixture of silica and stony matter foreign to the 

 composition of the dissolved mineral. When heated to redness, 

 it weighed four parts. 



b. The liquid from which the silver had been separated was 

 precipitated by sulphuretted hydrogen gas. The precipitate was 

 redissolved in uitromuriatic acid, and the acid liquid concentrated 

 till the whole nitric acid was decomposed. It was then diluted 

 with water, and sulphite of ammonia added. It became gradually 

 muddy, and of a cinnabar-red colour. After some hom-s, it was 

 boiled, adding fiom time to time small portions of sulphite of 

 ammonia. Tlie boiling was continued two hours to be quite 

 sure of precipitating the whole of the selenium. Collected on a 

 filter, dried, and almost fused on the filter, it weighed 26 parts. 



c. The liquid separated from the selenium and deprived by 

 boiling of the residual sulphurous acid, was precipitated by the 

 subciubonate of potash. The green precipitate being washed, 

 dried, and heated to redness, became black, and was peroxide of 

 copper. It weighed 27 parts, equivalent to 21-55 parts of 

 metallic copper. This oxide, dissolved in muriatic acid, and 

 mixed with an excess of ammonia, dissolved completely with the 

 blue colour of copper. The alkaline liquid from which the car- 

 bonate of copper had been separated, had still a green tinge. It 

 was concentrated, acidulated with muriatic acid, and, by means 

 of an iron plate. To part of copper was still separated from it, 

 which makes the whole of the copper to amount to 23-05. 



The liquid precipitated in b l3y sulphuretted hydrogen gas, 

 being deprived by boiling of the excess of gas, was mixed with 

 caustic ammonia, which occasioned a yellow precipitate, which, 

 when dried, weighed TS part. It was a mixture of oxide of iron 

 and alumina. 1 he liquid from which it had been separated was 

 iiiixed with an excess of subcarbonate of potash, and evaporated 

 to dryness. The saline mass, being dissolved in water, left a 

 white earth, which, when dried, weighed 3*1 parts. Sulphuric 

 acid, being mixed with this earth, occasioned an effervescence 

 with the production of gas. The hquid separated from this last 

 and evaporated became gelatinous, and deposited silica. It 

 appeared also to contain magnesia ; but I neglected it because 

 these earths Vvcre obviously foreign to the metallic mineral. 



The result of the analysis was : 



Silver 38-93 



Copper 23-05 



Selenium 26*00 



Foreign earthy matter 8-90 



Less 3-12 



100-00 



