854 Contributions to Chemistry from the 
as to throw the transmitted light directly upon the slit of the 
spectroscope. 
4, On the separation and estimation of cerium. 
gramme of oxyd is a good working proportion. The solution is 
then to be boiled and a hot solution of oxalic acid or oxalate of 
ammonia added. On cooling, especially when the solution has 
been well stirred with a glass rod, or shaken, the oxalate sepa 
ates in large crystalline grains of a pale rose-violet color. he 
precipitate is to be filtered off and well washed with boiling water, 
the washing being extremely easy in consequence of the coarse 
granular character of the precipitate. The filter is then to be 
pierced and the oxalate carefully washed down into a crucible, 
after which the water in the crucible may easily be removed by 
evaporation and the oxalate dried at a temperature of 100°C. 
The equivalents of lanthanum and didymium are so near to that 
of cerium that no very sensible error is committed by consider _ 
ing the mixed oxalates as consisting simply of CeO C,0, +829 
In mineral analyses in which the relative quantity of oxygen 
the acids and bases must be determined with accuracy, it may be 
desirable to ascertain the quantity of oxalic acid ina weighed 
alee of the oxalates by combustion with oxyd of coppet, 
rom this the acid in the entire precipitate may be found, and 
the oxygen in the three bases will then be one-third of the oxy: 
gen in the acid. 
5. On the quantitative separation of cerium from yttrium, alumin- 
um, glucinum, manganese, tron and uranium. 
The relations of the three metallic oxyds of the cerium 
to sulphate of potash have long been fainiliar to chemists, @ x 
have furnished methods of separation from other oxyds a 
Pinta ct « use. In examining this subject I have oe be : 
phate of soda possesses great advantages over sulphate of po" 
‘the double sulphates of sodium and the protoxyds of cerium, 
Janthanum and didymium, being ibeolntely insoluble 10 a 
rated solution of sulphate of soda. On the other hand, 
