g5 NEW METAL FOUND IN CRUDE PLATINA. 



all viiible impurities, was expofed to a red heat, for the par- 

 pofe of expelling the mercury. It was then digefted for fome 

 time in a fmall quantity of dilute nitro-muriatic acid, and fre- 

 quently fhaken, till the whole of the gold was diflblved, toge- 

 ther with' any impurities that might fuperficially adhere to the 

 grains of platina. 

 Solution of the (B 2.) Of the ore thus prepared, nearly 2| ounces were then 

 oreinnitro-mur. c |jfl- j vec j j n n j tr0 -muriatic acid, (diluted for the purpofe of 

 leaving as much as poffible of the fliining powder,) and the 

 whole fuffered to remain in a moderate fand heat, till com- 

 pletely faturated. 

 Precipitation by (^ 3.) Such a portion of this folution was then taken for 

 fal amrn. analyfis, as correfponded to 1000 grains of the prepared ore. 



An ounce of fal ammoniac was next diflblved in hot water, 

 and ufed for the precipitation of the platina. The precipitate 

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

 yielded 815 grains of purified platina. 

 RefU«al liquor (B 4.) The water ufed for warning this precipitate having 

 precipitated by b een added to the folution poured from it, a piece of clean zinc 

 was immerfed in it, and fuffered 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. J remained in folution. 

 The other metals had fublided, in the form of a black powder, 

 which I eftimated between 40 and 50 grains; but, as there was 

 no occation to weigh it with accuracy, I thought it better not to 

 dry this precipitate, for, if it be heated, the rhodium is in dan- 

 ger of being rendered infoluble. 

 Precipitate de- (B 5.) As I had previoufly afcertained that this precipitate 

 andLadbv°nkr[c wou ^ con{a ' n platina, rhodium, the fubitance called palladium, 

 acid; and then copper, and lead, the two laft metals were firft diflblved in 



diflblved (moft di j te nitric acid, aided by a gentle heat. The remainder, 



part) m nitro-m. 3 > J & » 



acid. after being wafhed, was digefted in dilute nitro-muriatic acid, 



which diflblved the greater part, but left as much as 4| grains 



undiffolved.* 



Addition of (B 6.) To the folution were added 20 grains of common 



ll7™khtZ d falt ; and ' wben the who,e had been evaporated to drynefs with 

 muriates of a very gentle heat, the refiduum, which I had found, from prior 



platina, palladi- 

 um and rhodium. • j t was pre fumed that this refiduum confifted principally of the 

 fait ofVhodhim metal calIed b Y Mr « Tennant Iridium ; but, as it was accidentally 

 was warned off miflaid, and was not examined, it might alfo contain a portion of 

 by alcohol. rhodium. 



expert- 



