W. Gibbs on the Platinum metals. 57 
Art. V.—Researches on the Platinum metals ; by Wo.Lcotr 
s, M.D. 
(Continued from vol. xxxiv, p. 342, Nov, 1862.) 
THE mass of mixed double chlorids, after the volatilization of 
the osmium and the separation of the iron and other impurities 
by washing with a concentrated and cold solution of chlori 
yg water and afterward with boiling dilute chlorhydric acid. 
The filtrate and washings are to be evaporated together on a water- 
bath to dryness, They contain the whole of the ruthenium and 
platinum present in the original solution. The mass upon the 
filter, which has a pale buff color, consists of the two insoluble 
double salts, : 
6NH, .Co,Cl,+Ir,Cl,, and 6NH, .Co,Cl,+-Rh,Cl,, 
and is perfectly free from ruthenium and platinum, 
_ This process is based upon the fact that the iridium and rho- 
dium double salts above mentioned are almost absolutely insol- 
uble in boiling water and in boiling dilute chlorhydric acid, 
while the ruthenium and platinum salts, which have respectively 
the formulas 
6NH, .Co,Cl,4+3RuCl,, and 6NH, .Co,Cl,+3PtCl,, 
are easily soluble. | 
wit tladium also forms with chlorid of luteocobalt a double 
- Salt which is easily soluble in dilute chlorhydric acid, and which 
Ax, Jour. 8c1.—Secoxp Serizs, Vou. XXXVII, No. 109,—Jan., 1864. 
8 
