CERIUM. 223 



Still another method was employed by Marignac. A defi- 

 nite mixture was made of solutions of cerium sulphate and 

 barium chloride. To this were added, volumetrically, solu- 

 tions of each salt successively, until equilibrium was at- 

 tained. The figures published give maxima and minima 

 for the BaCL, proportional to each lot of 062(804)3. In 

 another column, using the mean value for BaOlj in each 

 case, I put the ratio between 100 parts of this salt and the 

 equivalent quantity of sulphate. The latter compound was 

 several times recrystallized : . 



Ce^{SO^)^. Bad.,. Ratio. 



First crystallization.- Ii.oii grin. 11.990 — 12.050 gnn. 91.606 



__ 13.194 " 14.365 — 14.425 " 91-657 



Second " _. 13.961 " 15-225 — 15.285 " 91.518 



.. 12.627 " 13-761 — 13-821 " 91-559 



- II. 915 " 12.970—13.030 " 91-654 



Third " __ 14.888 " 16.223 — 16.283 " 91.602 



_- 14.113 " 15.383—15.423 '• 91.755 



Fourth " ._ 13. Ill " 14.270 — 14.330 " 91.685 



-13.970 " 15.223—15.283 " 91.588 



Mean, 91.625, rh .016 



Omitting the valueless experiments of Kjerulf,* we come 

 next to the figures published by Bunsen and Jegel t in 1858. 

 From the air dried sulphate of cerium the metal was pre- 

 cipitated as oxalate, which, ignited, gave CeO,- In the 

 filtrate from the oxalate the sulphuric acid was estimated as 

 BaSO, : 



1.5726 grm. sulphate gave .7899 gnn. CeO^ and 1.6185 g™!- BaSO^. 

 1.6967 " .8504 " I-7500 " 



Hence, for 100 parts BaSOi, the CeOo is as follows: 



48.804 



48.575 



Mean, 48.689, 4= .077 



One experiment was also made upon the oxalate : 



.3530 grm. oxalate gave .1913 CeO,^ and .0506 H^O. 



Hence, in the dry salt, we have 63.261 per cent, of CeO. 



* Ann. Chem. Pharm., 87, 12. 

 f Ann. Chem. Phann., 105, 45. 



