Analysis of Cerium Ochre. 505 



silica, alumina, lime, magnesia, and cerium, while fifty grains 

 were operated upon for the alkalies. Each analysis was re- 

 peated on similar quantities. The water was determined by 

 heating one hundred grains of the coarse powder to dull red- 

 ness. In the analysis for the alkalies, the first process was 

 by fusion with carbonate of barytes, and then another por- 

 tion was decomposed by fluor spar and sulphuric acid. In 

 the other operations, the analytical processes of Berzelius and 

 Rose were followed. It will be unnecessary to detail them in 

 this paper. 



Results of the Analysis reduced to per ceniage. 



Cont's. Ratio. 



45.940 — ox. = 23.865 = 4 



13.469 " 2 



u 



^=1 



4.160 

 1.389 

 0.598 

 0.108 

 " 0.078 



1.586 

 " 0.444 



99.949 

 Formula 2A Si + (Ca Na Li) Si'. 



The oxide of cerium, from its brown color after ignition, evi- 

 dently contains the oxide of lanthanium combined with it. 

 We have, as yet, no accurate process for their separation. 



ANALYSIS OF CERIUM OCHRE. 



The pink scapolite is frequently invested with a thin, 

 sulphur-yellow powder, resembling, in appearance, the native 

 oxide of molybdena. This I have analyzed, and find it to be 

 the hydrous oxide of cerium and yttria, containing minute 

 proportions of fluorine and uranium. 



One grain of this powder, scraped from a specimen of the 



scapolite, yielded 



Ox. cerium, 0.2 gr. 



Yttria, 0.1 gr. 



.3 



57 



