ii7 
Platina and Mercury upon each other. 
make them apparently one, has taken its full effect, it will not 
be easy to separate them ; and this will be more particularly 
the case when neither of those substances is remarkable for 
exercising a powerful action upon others. The method of 
analysis therefore does not promise much success; and the 
labour of synthesis is sufficient to deter any individual from 
the undertaking. 
It is my intention now to exhibit one example of my position, 
and to prove that platina and mercury act upon each other, in 
such a manner as to disguise the properties of both. I shall 
therefore wave for the present all consideration of palladium, 
which is in fact but a subordinate instance of the case before us. 
When a solution of green sulphate of iron is poured into a 
solution of platina, no precipitate, nor any other sensible 
change ensues. This I had already observed, and it has since 
been confirmed by all who have written upon the subject. But, 
if a solution of silver or of mercury be added, a copious preci- 
pitate takes place. This precipitate contains metallic platina 
and metallic silver or mercury ; some muriate of one or other 
of the latter metals is also present, as it is not easy to free the 
solution of platina from all superfluous muriatic acid. But 
these salts are of no importance in the experiment, and can 
be separated by such methods as a knowledge of their chemical 
properties will easily suggest. The proper object of conside- 
ration is the reduction of the platina to the metallic state, 
which does not happen when it is alone. I have tried to pro- 
duce the same effect with other metals and platina, but I have 
not observed any thing similar. It is therefore fair to conclude, 
that when a solution of platina is precipitated in a metallic state. 
