M. C. Lea on the Platinum Metals. . 253 
the reaction would be affected by the presence of other members 
of the group. Mixtures were therefore made of solution of pro- 
tochlorid of palladium with the following subst tive] 
Sesquichlorid of ruthenium, 
Bichlorid of ruthenium, 
= all 
(V.) 
REACTIONS WITH SULPHATE OF QUINIA. 
With sulphate of quinia, protochlorid of palladium gives a 
bulky buff colored precipitate, which becomes somewhat black- 
on boiling. Neither ruthenium nor iridium give similar 
reactions, 
(VI) 
REACTIONS WITH PROTOCHLORID OF TIN, 
Ru, Cl, boiled with SnCl becomes perfectly colorless, if the so- 
lution is yery dilute. Stronger solutions show a pale straw color. 
RuCl,, boiled with a small quantity of SnCl, gives a buff col- 
ored precipitate, which dissolves, in an excess of the precipitan 
to a solution which, by further treating, passes to a splendi 
blood-red of great intensity. : : 
The buff colored precipitate is soluble in solution of potash, 
producing an intense brown liquid. he 
Ir,Cl,. When the sesquichlorid of iridium and ammonium is 
boiled with SnCl, and potash added in sufficient quantity to re- 
dissolve the precipitate which it at first produces, further boiling 
produces an abundant leather-colored precipitate, which is insol- 
uble in any excess of potash. : : 
I felt much interested to observe whether this reaction would 
take place in the presence of sesquichlorid of ruthenium in the 
solution; and had the satisfaction to find that it did so. We thus 
ave a mode of detecting iridium in the presence of ruthenium, 
Which offers certain advantages. ee 
_ The best way to observe the reaction is as follows: To the 
_ Solution of sesquichlorid of ruthenium, edd a little acidulated 
Protochlorid of tin, and boil till the color disappears and then 
