F1.KTENDED NEW METAL; PALLADIUM. ^3 



abfolate weight of which exceeded that of the platina originally 

 employed. But, although this fubftance was not platina, I 

 could not fay it was palladium. The moil fuccefsfal experi- Experiment i. 

 ment by this method, was attended with the following cir. '^fj^fjj'g^ g"Jj 

 cumftances. I difTolved one hundred grains of platina in nitro- ment of forming 

 muriatic acid, and then put in two hundred grains of red oxide palladium by the 

 of mercury, made by nitric acid ; but this not being lumcient tioned. 

 to faturate the excefs of acid, I continued to add more, antil 

 it ceafed to be difTolved. On the other hand, I prepared fome 

 green fulphate of iron, and poured it into a long-necked 

 raattrafs. I then poured the mixed folution of platina and 

 mercury into the folution of green fulphate of iron, and heated 

 the whole upon a fand bath. In lefs than half an hour, a 

 copious precipitate was formed; and the infide of the mattrafs 

 was lined with a thin metallic coat. The liquor was pafTed 

 through a filtre, which I had weighed ; and the precipitate, 

 after digeftion with muriatic acid, was well wafhed and dried. 

 When I had colleded as much of this as I could, there re- 

 mained upon the filtre 12 grains ; betides which, I had colled- 

 ed264, in all 276. The fupernatant liquor flill contained a 

 portion of mercury, and about eight grains of platina. There- 

 fore, the 276 were compofed of 92 of platina, and 184 of 

 mercury. From this it appears, that one hundred grains of 

 platina, can determine the precipitation of near two hundred 

 grains of mercury, by green fulphate of iron; and that, in this 

 proportion, there is a reciprocity of faturation. The 264, 

 collecled from the filtre, were expofed to a low red heat, 

 and were reduced to 144. The twelve of the filtre would have 

 given about feven ; therefore, the whole would have been 1 5 J . 

 The fubflance was in the form of a fine powder, and had a 

 metallic luftre. It was then put into a charcoal crucible, and 

 fufed info a button. This button weighed 128 grains, and 

 with the quantity left on the fibre, would have weighed 135. 

 In this 135, there were 92 of platina; therefore it was com- It contamca ' 

 pofed of about two parts of that metal and one of mercury. ^^'^^^ ^^° P*^* 

 It was of the fpecific gravity of 1 1 ,2 ; was wholly foluble in mercury. - 

 nitric acid; was eafily fufed by fulphur; was precipitated by 

 green fulphate of iron : in a word, it was not to be diflinguifh- 

 ed from palladium. 



Exper, 2. As another mode of forming palladium in the Experiment a., 

 humid way, I put metallic iron into a mixed It^Iulicn of platina of'piatinaand* 



aDd ' 



