ON PLATINA, 123 



If cryftallized muriate of platina and foda, free from all ad- Its cryftals from 

 hering orexcefsof acid, be expofed for fome time to the air, ^.^come green bv 

 its beauti.ful red colour becomes changed into a greenifli hue. expofure to tJic 



If the fait in that ftate be dilTolved in water, and oxiginized ^tmofphere. 



. . ~ , Its fo:ution 



muriate of lime be added to it, a daric brown precipitate falls, p,ecip. by ox. 

 which after having been wafhed and dried, is foluble in mu- muriate oi'lime. 

 riatic acid, with which it fi)rms a beautiful blue foluiion. This 

 colour becomes again deftroyed by the admixture of alcohol, 

 and re-appear-; by the addition of oxiginized muriate of lime. 



This precipitate is fomewhat foluble in water; iti^s reducible ^''^'^'P'^^'^^ *"«>"«■* 

 ' ^ what fjlublej 



when filled with borax, without imparting to the latter any co- reducible into 



lour. The reduced metal is very porous: it appeared not to » po''°"s metal 

 ,-.,,,. „ , J infoluble in 



be loluble in any or the acids. acids. 



If the foluiion of muriate of platina and foda, contain an No precipitate 



excefs of acid, it then is not diOurbed by letting fall into it ^^^^'^l^ ''^ "" 



oxiginized muriate of lime; but on evaporation the mixture 



acquires a fine grem colour. 



Examination of the Ytlloiu and Red triple Muriate of Platina. 



If we add to the red triple muriate of platina, a folution of ■'^'^ V^^ J"P'^ 

 carbonate of foda, till it becomes completely diffolved the fo- yellow by carbo- 

 lution is of a yellow colour. On expofing it for fome time to "^'^ of foda; 

 the contadl of air, a green fubftance- becomes depofiled. ^^^^^ precip! ^bv 



The yellow triple muriate of platina, treated in a like man- expof- to the 



ner vviih carbonate of foda, yields a folution of a dark yellow, -j,^^ ,. , 



or orange colour, which fufFers no change whatever on expo- treated becomes 



fure to air. ^^'"^";' ^""^f « 



" afterwards 

 The feparation of the green fubftance from the red triple change. 



muriate, is much accelerated by the admixture of oxiginized Jl^e green depo- 



. . ., T r ■/• 1 /- • r , ■ r \ n "t from the red 



muriatic acid. It Jeems as ir the leparation or this lubltance triple muriate is 



is owing to the aftion of oxigen ; for no other acid is capable ^"^""^ oxidize- 



of producing it ; alleaft the precipitate which they produce, 



is a mere oxid of platina. 



The green fubftance may likewife be inftantly obtained by ]^ '^ inftantly 

 evaporating the folution by heat. t;o„^ ^ *^ "' 



If the folution of the yellow triple muriate be heated and The yellow 



evaporated, a very minute quantity of the green fubftance is may affbrd a'^ *- 



indeed, fometimes depofiied, and the remaining folution then nute portion of 



acquires a more beautiful yellow colour. On continuing the fva "— b^*^''i:*h 



evaporation of the yellow folution, a precipitate is depofited, is an impurity. 



which 1% ?>•«*?• »s 

 yellow* 



