54 C. Wolf on the equivalent of Cerium. 
r. Wolf may not be lost, but that they may induce some im 
restgntor to advance or conclude this pretly epper 
F. A. Gen 
ae April 26th, 1868. 
Since the discovery of the peculiar oxyds contained in 
cerite by Berzelius & Hisinger* and Mosandery they have 
the subject of numerous researches. Their occurrence togethe 
with their very similar chemical properties presented very great 
difficulties in their separation and indeed the mixture of 
three oxyds was for a long time looked upon as the oxy: 
one metal only, which was ‘called cerium. Notwithstanding 
many investigations made on this subject, the methods for 
ee. and purification of the three cerite-oxyds are 
The oxyd of cerium, which in its properties differs most f 
the oxyd of didymium and from lanthana, and which is 
most common, 1s more eadite obtained in a state of pe 
purity than either of the two others. 
_ The following investigation was made for the purpose of p 
penne salts of cerium of absolute purity, so as to detert 
ay them the equivalent of the metal, The material 
cerite. 
"The method rae for the preparation of the oxyds 
1 by Bunsen,{ with some slig 
and ice. It was then agitated until the water had become 
vas when it was a bi biter The saturated solutit 
ferward poure and the residue washed until # 
uid = tasteless and gave no further precipitate with 
amie es 
After havin ng been concentrated by evaporation this solu 
was precipitated by sulphydric acid and ‘ltered, The exce 
of sulphydric acid was driven off by heat, the liquid was 
api: by chlorine, oe which the excess of the latter f 
> Gavseling &. Hisicaey, Gehlen's Journ. der Chemie, ii, 397. 
+ Mosander, Journ. fur pract. © yi 
& Dubl. Phil. Mag., Oct. 1843. ®, XEx, 1843; Poke Ann., clvi, 1843; 
¢ Bunsen, Annale: 
@ der Chem. & Pharm, or tae 
