ACTION OF PLATINA AND MERCURV. 181 



not unliJiely, that a portion- of mercury may be retained in 

 foiution by the plalina, as weil as that a portion of the platina 

 may be precipitated by means of the mercury. The mean 

 refult, however, was that the precipitate by green fulphate 

 of iron confined of about 17 of mercury, and 83 of platina, 

 when tlie fpecific gravity was about 16. 



Witli regard to palladium, left it Hiould be fuppofed that The author con- 

 either my own obfervations, or thofe of others have given me [JJa"" Ibdium 

 caufe to alter my opinion ; I will add, that I have as yet feen ^s a compound, 

 no arguments of fufficient weight to convince me, in oppofition 

 to experiment, that palladium is a fimple fubflance. Repeated 

 feiili^re iq the attempt to form it I am tpo well accuftomed to, 

 i?ot to believe that it may happen in well conducted operations; 

 but four fuccefsful trials, yvhich were not performed in fecrel, fmce fourfuc- 

 are in my mind a fufficient anfwer to that obiedion. By deter- ^ersful expen- 



..■^ •* ■' merits were made 



ipmnig the prelent queUiqn we may overcome the prepol^ of forming jt. 

 feflion conceived by many againil the potTibility of rendering 

 mercury as fixed, at an .elevated temperature, as other metals : 

 we may be led to fee no greater miracle in this pompound 

 than in a metallic oifide, or in water, and be compelled to 

 take a middle path between the vilions of ^Ichemy on the one 

 hand, and the equally unphilofophical prejudices on tjie pthpr, 

 which they are likely to create. In the courfe of experiments 

 juft now related, I have feen nothing but what tends to con- 

 firm my former refults, yet the only means which I can, after 

 all, prefcribe for fucceeding, is nerfeverance. 



To afcertain whether the opinion of Metf. P'ourcroy and Platina, purified 

 Vauqqelin, that the new metal was the principal ingredietit y^^^'^^Jf^^^"^ 

 in palladium had any juft foundation, I obferved the methods method, h 



they have recommended for obtaining pure platina ; but I did ^^"ally combm- 

 ' . ..^ . ,..,.., ' , . , able with mer- 



not perceive any difference m the facility \vilh which either cury. 



kind of platina combined with mercury. 



I might have added fome more experiments to corroborate Thefe chemlfts 



the evidence I have adduced to prove my affertion of th e J"'^ ^^- ^'f f J 



^ ■' _ have prom: led to 



fixation oi mercury by platina ; but MefT. Vauquelin and puj^fue the fub- 

 Fourcrpy have promifed the Inftitute of France a continuation J^'^* 

 of their refearches, and M. Richter concludes his paper with 

 faying that he will return to the fubje6^. From the labours of 

 fuch perfons (bme great and important fafl muft iffue, ^and I 

 hope that the prefent fubjed will not be excluded from tijteir 

 confideration. The fads contained in this paper cannot Ipe 

 3 fubiuitted 



