98 



PRETENDED NEW METAL; PALLADIUM. 



Anafytical ex- 

 periments not 

 luccefjful. 

 Exce fs of mer- 

 cury added to 

 folution of pal- 

 ladium. 



Palladium 

 ftrongiy and 

 durably heated. 



Cupellatlon. . 



Combuftion In 

 oxigen. 



by gdvairifm. 



Wonderful dif- 

 ferences between 

 mixture and 

 combination. 

 Affinity not pro- 

 portioned to the 

 facility of union. 



ANALYTICAL EXPERIMENTS. 



Exp. 1, 2, and 3, The converfe of the fynthetlcal experi" 

 ments 1, 2, 3, was made, but without any fatlsfadtory refult. 



Exp. 4. The converfe of Eip. 4 was made without fuc- 

 cefs. I put fome mercury into a folution of palladium, and 

 left them to^^ether for fome time. The precipitate which was 

 formed was palladium, juft as it had been uled for the opera- 

 tion. 



Exp, 5. I expofed different pieces of palladium to a very 

 violent heat for two hours. In fome, a diminution of abfolute 

 weight, with an increafe of fpecific gravity, took place; in 

 others, neither of thefe effects was produced. The fpecimens 

 which I had made were chiefly of the latter kind. 



Exp. 8. Cupellation did not afford any fatisfaflion refpe^t- 

 ing the analyfis of palladium ; but the heat neceflary for this 

 purpofe is fo great, that I could not place great reliance upon 

 this experiment. It is difficult to detach the button from the 

 cupel with accuracy. 



Exp, 7. I burned fome palladium In oxigen gas. A white 

 fmoke arofe during the combuftion, and was depofited upon 

 the fides of the glafs jar that contained the gas. But this fmoke 

 was palladium, and not the mercufy feparated from it. 



Exp. 8. A flip of palladium, which Mr. Davy bad 4ho 

 goodnefs to expofe, in my prefence, to the adtion of the ftroiig 

 galvanic batteries of the Royal Inftitution, burned with a very 

 vivid light, and a white fmoke ; but no mercury was feparated 

 by this operation. 



. There is not any property of this compound which appears; 

 to me fo wonderful, as that which is raanifefted by thefe ex- 

 periments. It is a ftriking proof how unfounded was the 

 opinion of fome philofophers, who fuppofed that the rapidity 

 of combination was a meafure of the force of affinity. We 

 do not know of any affinity among chemical bodies which is 

 more powerful than that of platina and mercury appears to be. 

 The obftacles which m\ift be overcome, in order to fix the 

 latter metal, are a proof of this ; yet the difficulty of forming 

 this combination to its full extent is extreme. The difference 

 which exifts between the compound and its elements,. v\'hen 

 merely mixed, either, in folution or othervvife, cannot be 

 ! uis^-ar;. better 



