1 70 On a new Metal, found in crude Platinei, 



(B 2.) Of the ore thus prepared, nearly 21 ounces were 

 then dissolved in nitro-miiriatic acid, (diluted for the purpose 

 of leaving as much as possible of the shining powder,) and 

 the whole suffered to remain in a moderate sand heat, till 

 completely saturated. 



(B 3.) Such a portion of this solution was then taken for 

 analysis, as corresponded to 1000 grains of the prepared ore. 

 An ounce of sal ammoniac was next dissolved in hot water, 

 and used for the precipitation of the platina. The precipi- 

 tate obtained was of a yellow colour, and, upon being heated, 

 yielded 813 grains of purified platina. 



(B 4.) The water used for washing this precipitate hav- 

 ing been added to the solution poured from it, a piece of 

 clean zinc was immersed in it, and suffered to remain till there 

 appeared to be no further action upon the zinc. The iron 

 contained in the ore (to the amount of 14 or 15 per cent.) 

 remained in solution. The other metals had subsided, in 

 the form of a black powder, which I estimated between 40 

 and 50 grains; but, as there was no occasion to weigh it 

 with accuracy, I thought it better not to dry this precipitate; 

 for, if it be heated^ the rhodium is in danger of being ren- 

 dered insoluble. 



(B 3.) As I had previously ascertained that this precipi- 

 tate would contain platina, rhodium, the substance called 

 palladium, copper, and lead, the two last metals were first 

 dissolved in very dilute nitric acid, aided by a gentle heat. 

 The remainder, after being washed, was digested in dilute 

 ritro-muriatic acid, which dissolved the greater part, but 

 left as much as 4-^ grains undissolved*. 



(B 6.) To the solution were added 20 grains of com- 

 mon salt; and, when the whole had been evaporated to 

 dryness with a very gentle heat, the residuum, which I had 

 found from prior experiments, would consist of the soda- 

 muriates of platina, of palladium, and of rhodium, was 

 washed repeatedly with small quantities of alcohol, till it 

 came off nearly colourless. There remained a triple salt of 

 rhodium, which by these means is freed from all metallic 

 impurities. 



(C 1.) This salt, having been dissolved in a small quan- 

 tity of hot water, and let to stand 12 hours, formed rhom- 

 boidal crystals, of which the acute angle was about 73"^. 



(C 2.) It was then again dissolved in water, and divided 

 into two equal portions. Of these one was decomposed by a 



• It was prebumcd that this residuum consisted principally of the me" 

 tsl called by Mr. Tennant iridium ; but, as it was accidentally mislaid, 

 and was not examined, it might also contain a portion of rhodium. 



piece 



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