ON PALLADIUM. 123 



amalgam had been expofed to a red heat, there remained a which it formed 

 white melal, which could not be fufed before (he blowpipe. It an/[he mercury 

 gave a red folulion as before in nitrous acid; it was not was driven of by 

 precipitated by fa! ammoniac, or by nitre; but by pruffiate p^j^^j.^^'^ ^^^ 

 of polafti it gave a yellow or orange precipitate; and in the 

 order of its affinities it was precipitated, by mercury but not 



The'e are the properties by which I originally difiinguiflied 

 palladium; and by the affiftance of thefe properties I obtained 

 a fuflk-ient quantify for inveftigating its nature more fully. 



There were, however, various reafons which induced me to The proccfs 



relinquifli the original procefs of fohilion in nitrous acid and ^ mercury 



/ . . =• * was abandoriedj 



precipiiation by m.ercury ; for although I found the metal thus 



obtained to he nearly pure, the necetlily of agitating the folu- 

 lion with the mercury was very tedious, and the wafte wasalfo 

 confiderabie ; for in the firfi place it feemed that nitrous acid 

 would not extra6t all the palladium from any quantity of the 

 fecond metallic precipitate, neither would mercury reduce the 

 whole of wliat was (b diffolved^ 1 therefore (ubftituted a 

 procefs dependent on another of it^ properties I had obferved 

 that this metal differed from platina in not being precipitated 

 from nitro-muriatic acid by nitre or by other fiilts containing 

 potafii ; for although a triple fait is thus formed, this fait is 

 extremely foluble, while that of platina on the contrary re- 

 quires a large quantity of water for its folution. On that 

 account a compound luetijiruum confifling of nitrate of'potafli 

 dilpjlved in muriatic acid Is unfit for the folution of platina, 

 but dilfolves palladium nearly as well as common nitro-mu- 

 riatic acid in which there is no polafh prefent *. 



In five ounces of muriatic acid diluted with an equal quantity and a folvent 



of water, I ditrolved one ounce of nitrp, and formed a folvent '^on^'ting "f 

 /• ,1 1 , rr n- 1- 1 /• o • i • munatic acid, 



tor palladium that polleijes little power of acting on platma, vvith nitre was 



fo that by digefling any quantity of the fecond metallic preci- "''^'^ '" the fe- 



pitate till there appeared to be no farther a(51ion, I procured tio"nfro^'^'j,kli 



a folulion from which by due evaporation were formed cryfials it takes palla- 



of a triple fait, confifling of palladium combined with muriatic \^^ ^^ "°^ 



acid and polafii. Tiiele are the cryftals which I have on ^ jhe Mut'ion 



* I have found that gold may alfo be dilTolved with equal facility j^'ipie f/it of pal- 

 by the fame folvent, and nearly in the fame proportion. Ten grains paJladium potafli 

 of nitre added to a proper quantity of muriatic acid are fufficieat ^"'^ "^"fat'c 

 fJv Cx-teen grains of either gold c palladium. 

 ;. • former 



