gi 6 Mr. Chenevix's Enquiries concerning the Nature 
muriatic solution of the latter metal. If mercury be present, the 
colour is much darker. Recent muriate of tin, poured into a 
solution of the muriate formed by the red oxide of mercury, 
converts it into the muriate formed by the less oxygenized acids ; 
but, shortly after, the mercury is reduced to the metallic state. 
Hence it was, that the alloy of platina and mercury always 
gave a deeper coloured precipitate than platina, with muriate 
of tin. 
Neither platina nor mercury are precipitated by prussic acid, or 
by the prussiates. But, if sulphate, nitrate, or muriate of platina 
be poured into prussiate of mercury, an orange-coloured precipi- 
tate is immediately formed ; and, in some cases, a mixed solution 
of platina and mercury gives a similar precipitate by prussic 
acid alone. 
Platina is one of the metals which are precipitated by sul- 
phuretted hydrogen, without the necessity of a double affinity. 
The affinities of platina differ much from what is generally 
stated in the tables. By the few acids I have had occasion to 
try, oxide of platina is attracted in the following order: sul- 
phuric, oxalic, muriatic, phosphoric, fluoric, arsenic, tartaric, 
citric, benzoic, nitric, acetic, and boracic. 
That sulphuric acid should attract the oxide of platina with 
greater force than the muriatic, is an unanswerable argument 
to an opinion which was long supported by many philosophers, 
and which is not yet altogether abandoned by them. Muriatic 
acid has been said to contribute to the solution of gold or platina, 
in nitro-muriatic acid, in the same manner as sulphuric acid is 
supposed to promote the decomposition of water, during the 
solution of iron by that acid diluted. The affinity of muriatic 
acid for the oxide of gold or of platina, has been looked upon 
