jog ON PALLAITfUM. 



the precipitation of the palladium. Generally for a few feconoN, 

 and fometiines for a few minutes, there will be no appearance 

 of any precipitate ; but in a (hort time the whole folution be- 

 comes flightly lurbid, and a flocculent p»ecipilaie is gradually 

 Heat difengages formed, of a pale yellowith-white colour. This precipitate 

 the pure metal confifts wholly of pruffiate of palladium, and when heated 

 which IS not ,,,/.•..., . • n • x' 



more than one will be found to yield that metal ni a pure Itate, amountmg to 



t>vohund. part of about four or five tenths per cent, upon the quantity of ore 

 the origintl ore, ..„ , , 

 diflblved. 



The pruffiate of mercury is peculiarly adapted to the pre- 

 cipitation of palladium, exclulive of all other roetaU, on account 

 of the great affinity of mercury for the pruffic acid, which in 

 More mercury this cafe prevents the precipitation of iron or copper ; but the 

 does not aug- proportion of mercury does not by any means influence the 

 iuQ. quantity of palladium, for I have in vain endeavoured, in 



the above experiment on crude platina, to obtain a larger 

 quantity of palladium that I have ftated by uling more of the 

 pruffiate of mercury, or to procure any precipitate by the fame 

 means from a folution of pure platina. 

 The decompo- The decompofition of muriate of palladium by pruffiate of 

 fi^on is by double mercury is not effeaed folely by the fuperior affinity of mer- 

 cury for the muriatic acid, but is affifted alfo by the greater 

 affinity of pruffic acid for palladium ; for I have found that 

 pruffiateof palladium may be formed by boiling a precipitated 

 oscide of palladium in a folution of pruffiate of mercury. 

 Pruffiate of The pruffiate of mercury is confequenjly a teft by which 



mercury is the the prefence of palladium may be dete6led in any of its folu- 

 diur^. tions; but It may be worth obferving, that the precipitate 



obtained has not in all cafes the fame properties. In general, 

 this compound is afJedled by heat fimilarly to other priffiates, 

 but when the palladium has been diffijived in nitrqus acid and 

 precipitated from a neutral folution by pruffiate of mercury, 

 the precipitate thus formed has the properly of detonating 

 The precipita- "''^^" heated. The noife is fimilar to that occafioned by firing 

 tion trora a ni- an equal quantity of gunpowder, and accordingly the explo- 

 dmnaS by'low ^'°" '' attended with no marks of violence unlefs occafioned 

 heat. by clofe confinement. The heat requifite for this purpofe is 



barely fufficient to melt bifmuth, confequently is about 500* of 

 Fahrenlieit. The light produced is proportionally feeble, and 

 can only be feen in the abfence of all other h'ght. 



In 



