from the Oaralian Mountains in Siberia. 5 



acid. This solution, which was of a reddish brown co- 

 lour, let fall a yellow precipitate on the addition of muriate 

 of ammonia, and a deep red precipitate by the muriate of 

 tin at the minimum of oxidation : it suffered no precipita- 

 tion by prussiate of potash, and formed with soda a triple 

 salt of a beautiful red colour. It was therefore no other 

 than a portion of platina which had been separated from 

 the crucible by the six successive manipulations ; and there 

 was every reason to believe that the alkali and acid had 

 completely dissolved the constituent ingredients of the mi- 

 neral in question. 



Examination of the Alkaline Solution. 



2. This solution had a very beautiful deep yellow colour. 

 The last portions of the solution had a greenish tinge, 

 which disappeared on the spontaneous deposition of a 

 brown substance in small quantity, which I discovered to 

 be oxide of manganese. I poured, by degrees, into the so- 

 lution, evaporated to one-half its former bulk, such a quaii- 

 titv of nitric acid as saturated the caustic portion of alkali ; 

 and a precipitate fell to the bottom, which I collected upon 

 a filter, then washed it, and submitted it to calcination. It 

 weighed 1 1 hundredth parts, and was set aside for future 

 examination. 



The addition of a slight excess of nitric acid produced 

 no precipitation but merely a violent effervescence, and 

 caused the solution, to assume a very deep orange red co- 

 lour. When evaporated to dryness it left a saline residuum 

 of a fine vellow colour, whicii dissolved completely in wa- 

 ter : the solution, when acidulated with nitric acid, furnished 

 by the nitrate of mercury a red precipitate, which after 

 being dried in the air weighed 430 parts ; and these by cal- 

 cination were reduced to 52 hundredth parts of an oxide of 

 chrome, having a beautiful green colour. 



3. The matter precipitated in No. 2 by the nitric acid 



was melted with three parts of caustic potash ; and the 



nias5, when mixed with water, dissolved completely in 



muriatic acid. The solution, when evaporated to dryncs«, 



A 3 left 



