=  Govered with filter paper for some time. Treated in te way 
84 M. C. Lea on the Platinum Metals. 
takes place, and the iridium salt is rapidly reduced. As fast as 
e effervescence ges more oxalic acid is sre until pags 
additions cease to produce any effect. When this is the 
= liquid is me to boil for two or three minutes longer, 10 : 
ore; the heat is to be removed, and the flask cre intocold 
nt : 
oi 
the aunt of water dateees “The salammoniac may be added 
r 
ence of rine preity has been hitherto an eenveed or 
could only be effected by Claus’ method of allowing a small 
quantity of water acidulated by a ie to 3 in 
eontact with the iridium salammonide for e day ne 
ruthenium salt, by its superior solubility, wrided ned “dissol¥é 
first, hence the ‘acidulated water after standing contained ruthe- 
nium in larger relative proportion than the original crystals— 
the ruthenium reactions were more marked, and if it was pres- 
ent and in sufficient quantity, it could be detected by sulpho- 
= of potassium, or better, to an experienced eye, by acetate 
of lead. he objections to this method are sufficiently obvious. 
T shall presently describe a reaction which will detect ruthenium 
in the presence of any quantity of iridium, and, scrutinized by 
that test, the iridium prepared in the manner which I have just 
described, is free from ruthenium, as well as from the other more 
easily separable cognate metals. 
| The treatment of solutions (B) and (C) presents no Seeger 
With (B) the best plan is to place the solution aside in a beaker 
 bichlorid gradually erystallizes out, and by recrystalliza- 
ms may be obtained in a state of bax purity. 
olution (C) is to be evaporated to ess and reduced to an 
le powder. it is then to be t <sheutes ara filter and 
ee, 
