of a metallic Substance called Palladium. 299 
most favourable circumstances for that affinity to exert its 
influence, and to promote their union, is not the result of com- 
mon methods. Among a great number which I have tried, many 
have failed, and none have been attended with uniform success. 
I have, however, formed palladium by the immediate union of 
platina and mercury ; and, as whatever may place the apparent 
capriciousness of this combination in a conspicuous point of 
view is not devoid of interest, I shall describe the means by 
which I have attempted to produce it, whether they failed, or 
were attended with success. 
SYNTHETICAL EXPERIMENTS. 
Exper. 1. It was not till after repeated trials of the mode just 
mentioned, that I succeeded in forming palladium. In many 
instances, I obtained a button completely melted, of the specific 
gravity of 13, and sometimes more; not so easily fused by sulphur 
as palladium ; not soluble in nitric acid ; and the absolute weight 
of which exceeded that of the platina originally employed. But, 
although this substance was not platina, I could not say it was 
palladium. The most successful experiment by this method, 
was attended with the following circumstances. I dissolved one 
hundred grains of platina in nitro-muriatic acid, and then put 
in two hundred grains of red oxide of mercury, made by nitric 
acid ; but this not being sufficient to saturate the excess of acid, 
I continued to add more, until it ceased to be dissolved. On the 
other hand, I prepared some green sulphate of iron, and poured 
it into a long-necked matrass. I then poured the mixed solution 
of platina and mercury into the solution of green sulphate of 
iron, and heated the whole upon a sand bath. In less than half 
an hour, a copious precipitate was formed : and the inside of the 
