lOS On the Action of 



sibly diminish it. It yields more easily than platina to the 

 action of" nitro-muriatic acid, and its solution in that acid, 

 when neutralized, gives a precipitate, as in the former ex- 

 periment, bv green sulphate of iron. If this precipitate be 

 exposed to a strong heat after it has been boiled with nitric 

 acid, ii loses a great part of its weight, and the platina alone 

 will generallv be found to remain. 



\E.rp. 3. When a quantity of ammoniacal muriate of pla- 

 tina is treated according to the method of count Mnssin 

 Pushkin to form an amalgam, and, after being rubbed for 

 a considerable time with mercury, is exposed in a crucible 

 to a heat gradually increased till it becomes violent, a me- 

 tallic powder remains in the crucible. This powder is acted 

 upon by nitro-nmriatic acid, and when the solution is neu- 

 tralized a copious precipitate is formed upon the addition 

 of green sulphate of iron. This effect takes place even after 

 the metal has been fused in the manner described in the 

 former part of this paper. 



Exp. 4. If sulphur be added to the ingredients recom- 

 mended by count Mussin Pushkin, and the whole treated 

 as in the last experiment, the quantity of precipitate caused 

 by green sulphate of iron in the nitro-niuriatic solution of 

 tU^ button which results from the operation is generally 

 more considerable. 



Exp. 3. If sulphur be rubbed for some time with ammo- 

 niacal muriate of platina, and the nuxture be introduced 

 into a small Florence flask, it can be melted on a sand-bath. 

 If mercury be then thrown into it, and the whole be well 

 stirred together and heated, it may afterwards be exposed 

 to a verv strong fire and melted into a button. If this be 

 dissolved in nitro-muriatic acid, it will give a precipitate, 

 as in the former cases, by green sulphate of iron. 



Exp. 6. If a current of sulphuretted hydrogen gas be 

 sent through a mixed solution of platina and mercury, and 

 the precipitate which ensues be collected, the metal may be 

 reduced by heat; and with the addition of borax it may be 

 melted into a button which will not contain any sulphur. 

 Green sulphate of iron causes a precipitate in the solution 

 of this rnctal also. 



Exp. 7. If to a mixed solution of platina and mercury 

 phosphate of ammonia be added, a precipitate takes place. 

 If this be collected and reduced, it will be acted upon by 

 frieen sulph-i'e of iron poured into its solution, in the same 

 manner as the metallic buttons in the preceding examples. 



Exp. &. I have already mentioned that when a solution 

 of nitrate of mercury, at the minimum of oxidizement, is 



poured 



