1835.] Chemical Analysis of Gadolinite, fyc. 423 



grs. of peroxide of cerium. The weight was not altered by 

 nitric acid. The residual liquid containing the oxalic acid 

 was accidentally lost ; but, from the preceding experiment, 

 we may deduce the composition of the salt as follows : — 



Peroxide of cerium ... 10* or 7' - 1 atom. 



Oxalic acid 9*57 ,, 6*75 - 1 J atoms. 



Water 1*03 „ 0-75 - \ atom. 



20-6 , 



9. Disesqui-phosp hate of Cerium — 8*3 grs. peroxide = 7*7 

 grs. protoxide of cerium were digested in muriatic acid, 

 and the solution evaporated to dryness. The white matter 

 remaining after being again dissolved in water was precipi- 

 tated by phosphate of soda. The white precipitate collected 

 on a filter, well washed and dried, weighed 12*2 grs., reduced 

 by ignition to 1 1 *09 grs . Its colour had now become greenish- 

 yellow. It was hard, compact, and semivitreous, but with- 

 out tHe least appearance of having been fused. 



It is obvious that the constituents of this salt are, 

 Protoxide of cerium . . 7*70 or 10*22 - 1 J atoms. 

 Phosphoric acid . . . 3*39 ,, 4*5 - 1 atom. 



11-09 



10. Disesqui-phosp hated peroxide of Cerium. — 10 grs. of 

 peroxide of cerium were dissolved in nitric acid, and gently 

 evaporated to dryness. The red mass obtained was dis- 

 solved in water, and .precipitated by phosphate of soda. The 

 precipitate, which was slightly yellow, was collected on a 

 filter, well washed and dried. It weighed 16*42 grs. 

 reduced by ignition to 14*23 grs. It had exactly the colour, 

 lustre, and appearance of the preceding salt. 



Its constituents were 



Peroxide of cerium ... 10* or 10*63 

 Phosphoric acid ... 4*23 ,, 4*5 



This is obviously 1J atoms of peroxide of cerium, and 

 ! atom phosphoric acid. Thus, in its constitution, it agrees 

 with the former salt. The only difference between them 

 being the different states of oxidizement of the cerium. 



The preceding experiments were made with a view of 

 determining the atomic weights of yttria and cerium with 

 more accuracy than could be done formerly, when the 



