60 W. Gibbs on the Platinum metals, 
chlorid of luteocobalt is extremely convenient when it is desired 
to obtain pure ruthenium or rhodium at once from the osmium- 
iridium. 
ployed to reduce the IrCl, to Ir,Cl, may exercise a reducing 
action on the Ru,Cl,, it will be found advantageous after wash 
ing out the RuCl, KCl and Ru,Cl, 2KCl, to convert the Ru, 
Cl, 2KCl entirely into RuCl, KCl. This may easily be accom: | 
plished by adding a solution of caustic potash in excess and then — 
of hyper-ruthenic acid is observed. By adding nitric acid im 
excess so as to dissolve the black precipitate at first produced 
and then evaporating to dryness with an excess of chlorhydri¢ 
acid, the whole of the ruthenium will be brought into the form 
of RuCl, KCl. , 
When a solution of chlorid of luteocobalt is added to one con- 
taining bichlorid of fvidiutl® 
is thrown down, consisting of a salt which has the formula 
rC 
platinate of potassium, after repeated crystallization, obstinately 
retains a reddish or deep orange tint arising from traces of the 
Balt, as well as the separation of rhodium from platinum, ruthe 
‘ium and palladium. TI shall return to this ma i 
“of the metals of this group separately and will then point out — 
