of a metallic Substance called Palladium. 305 
is, an alloy which is a mean betwixt platina in its pure state and 
what has been called palladium. It is, consequently, subject to 
infinite variation. The first effects which mercury produces upon 
platina are, to render it more fusible, and to diminish its specific 
gravity. The next new property conferred upon it is, the power 
of uniting with sulphur ; and, lastly, it becomes soluble in nitric 
acid. It is not however till the specific gravity is below 12, or 
12,5 at most, that it has acquired this property; and all these 
effects follow the direct order of the increase of weight observable 
in the platina. 
It is not very difficult to combine a small quantity of mercury 
with platina : but, to resolve the problem completely, and to pro- 
duce an alloy of these metals which shall be of so low a specific 
gravity as 11,3, and shall be soluble in nitric acid, is not so 
easily accomplished. From the repeated failures which I have 
experienced in these operations, I am much inclined to think 
that the author of palladium has some method of forming it, 
less subject to error than any I have mentioned. No doubt 
that perseverance would put us in possession of his secret; 
but, being prevented by want of leisure from pursuing these 
researches at present, I have confined myself to establishing the 
fact, and describing the processes which I have employed. 
Having thus acquired a certainty that mercury is a constituent 
part of palladium, I made some further experiments upon it, 
with a view to its analysis ; but they have hot been attended with 
so much success. It might be expected, from the great number 
of methods which have failed to form palladium, that many 
might be found to decompose it when formed. But I have 
found the converse of such processes as did not succeed in pro- 
ducing palladium, to be ineffectual in destroying the combination. 
