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PROOFS OP THE PROPERTIES OP PLATINA.

Experiment II.

Separation of platina from gold.

When gold is alloyed with platina, die adulteration cannot bediscovered by hydrostatic examinations ; but as muriate of am-,monia has the property of precipitating platina, but not gold fromthe solution ; and as fresh prepared sulphate of iron precipitatesgold (seepage 108 ) but not piafina, these salts furnish the meansof separating the metals when added to the solution.

Experiment III.

Platina coml-ines with phosphorus.

(Phosphuret of platina.)

Mix equal parts of platina and glacial acid of phosphorus withan eighth part of charcoal, put the whole into a crucible, andcover it with a little charcoal dust; expose it to a heat nearlyequal to that.which makes gold enter into fusion, and continue itfor an hour; a button of a silver-white colour will then be ob-tained, which exhibits in the inside, crystals of a perfect cubi-cal form ; this is phosphuret of platina.

Experiment IV.

Phosphuret of platina detonates with oxigenated muriate ofpotash.

If a mixture of phosphuret-of platina and oxigenated muriateof potash be thrown into an ignited crucible, a strong deto-nation ensues, and die platina becomes separated in its metallicform.