172 ACTION OV PtATlNA AND MERCUltY. 



a few fads are dated in my firft Paper in fupport of the 

 opinion, that palladium is but a particular inlknce of a gene- 

 ral truth. 

 Conclofion: By taking tl>e reafoning on this fubjedt tlien, in its wideft 



mtuh'^°y''ht ^^«"^ w« ^""^^ be led, I think, to the following conclufion : 

 taken for fimple, That metals may exercife an action upon each other, even in 

 b^tx^cmel'^''"' their metallic ftate, capable ot fo altering lome of their prin- 

 <tfficult. cipal properties as to render the prefence of one or more of 



them not to be detected by the ufual methods. In this is con- 

 tained the poffibilily of a compound metal appearing to be 

 fimple; but to prove ibis mud be a work of great time and 

 perfeverance ; and can only be done by conlidering fmgly 

 ai>d fucceffively the different cafes which it conlains, and by 

 wiftituling experiments upon each. When an afiinity which 

 unites two bodies, and fo blends their different properties as to 

 make them apj)arently one, has taken its full effed, it will not 

 be eafy to feparate them ; and this will be more particularly 

 the cafe when neither of thofe fubftances is remarkable for 

 ^xercifmg a powerful adion upon others. The method of 

 anal)fis therefore does not promife much fuccefs j and the 

 labour of fynthefis is fufficient to deter any individual from the 

 undertaking. 

 Pbtina and mcr. It is my intention now to exhibit one example of my 

 cury do at on p^jgtJQ,,^ and to prove that platina and mercury ad upon each 

 djfgnifc the pro- other, in fuch a manner as to difguil'e the properties of both. 

 perues oi each, j j^^^jj tjigfefore wave for the prefent all confideration of 

 palladium, which is in fad but a fubordinate inflance of the 

 cafe before us. 

 Example. Plati- When a folution of green fulphate of iron is poured into a 

 "rfthc^mctallir'^ folulion of platina, no precipitate, nor any other fenfible 

 ftate hy green change enfues. This I had already obferved, and it has lince 

 fulph. or'iron, if jj^^j^ confirmed by all who have written upon the fubjed, 



mercury or filver . ■ r , ■ r r, r i.., • 



beprcfcntj but But, if a lolution oi iilver or of mercury be added, a copious 

 not c\k. precipitate takes place. This precipitate contains metallic 



platina and metallic filver or mercury ; fome muriate of one or 

 other of the latter metals is alfo prelent, as it is not eafy to free 

 the folution of platina from all fuperfiuous muriatic acid. But 

 thefe falts are of no importance in the experiment, and can 

 be feparated by fuch methods as a knowledge of their chemical 

 properties will eafily fuggeft. The proper objed of confide 

 ration is the redudion of the platipa to the metallic ftate, 



which 



