OF COBALT, &c. 417 



rafters, in Sweden *. Moil agree, from experi- 

 ence; that the three firft of the above-mentioned 

 nc\V metals are, in their naturo, eflentially dif- 

 ferent from all other metals. There are, how- 

 ever, many who think thefe not to be primary, 

 fiinplc metals, but of a compound character. But 

 the cagmiefs with which chcmills entered upon 

 an invefligation of the relations of thcfc metals, 

 has now thrown light upon many of the difficul- 

 ties which they at firft prcfcnted. Yet, I don't 

 know that any body has examined them by folu- 

 tion and precipitation in different mcnflrua. I 

 have therefore been induced to fubjecl them to 

 thefc procefles ; and ihall proceed to relate my 

 experiments and obfervations. 



x i . Ex a mi nation of Platina by Precipitation. 



I HAVI: elfc where given an account of the rc- 

 iults obtained by the folution of platina in alka- 

 line falts. The only thing which I fhall herc- 

 add, is, that no alkali, whether vegetable or mi- 

 neral, aerated or cauftic, produces any precipita- 

 tion of platina that is adually diflblvcd. Tli6 

 colour of the precipitate is yellow, inclining more 

 or lefs to red ; but when evaporated to dryncis, 

 it becomes bluck. A foiution of an hundred 

 D d weight 



* A&. Upfal. 1733. A6\. Acad. Succ. 1751, 17521 

 1774- N. Ad. Upfal, vol. ii. p. 135, 246. Schcffcr'* Chem. 

 I'orclafi!, p. 39. 



