W. F. Hillebrand — Composition of Yttrialite. 149 



ammonium oxalate and thiosulphate methods. The weighed 

 thoria was pure white, the ceria of a pale salmon color. 



The condition of the uranium was shown by its precipitabil- 

 ity as tetrafluoride on dissolving the mineral in hydrofluoric 

 acid. This reaction afforded a ready means of estimating with 

 exactness the ferrous iron by permanganate after rapidly filter- 

 ing off the fluorides precipitated in an atmosphere of carbon 

 dioxide. Solution of the mineral in a sealed tube with dilute 

 sulphuric acid allowed of finding the oxygen value of both 

 U0 2 and FeO by permanganate. The result thus found for 

 OU 2 agreed marvelously well with that calculated from the 

 U 3 8 found gravimetrically in a separate portion. 



An 



of Yttrialite. 



Hillebrand. 



Si0 2 

 Ti0 2 

 Th0 2 

 U0 2 



Ce 2 3 

 La 2 Q 3 , etc. 

 Y 2 3 ', etc. 



A1 2 3 



Fe 2 3 



FeO 



MnO 



PbO 



CaO 



MgO 



H g O + 



h;o- 



co 2 



p 2 o 5 



N, He 

 Fl, Alk 



29-G3 



•05 



10-85 



1-64 (1 



3-07 



5-18 (2 | 

 43-45 (3 | 



Mol. Ratios. 

 •4938 



•0470 



105 C. 

 105 C. 



j-Diff. 



76 

 96 



8.8 



80 

 67 

 16 

 32 

 04 

 11 

 12 



31 



y -1930 



I 



I 



)- '0608 

 l 



I 



Mackintosh. 



29-17 



12-00 



•79 



1*86 



2-94 



22-67 



5-30 



450 



14-03 



•55 



(1 



(2 

 8 

 4 



(6 



Mol. Ratios. 

 •4861 



•0483 



1864 



•77 

 •85 

 •60 



79 



•0655 



100-00 



99*75 



1) Volumetrically. Gravimet- 1) Given as -83U0 3 by Mackin- 



rically 1-62$. tosh. 



2) At. W. 143-8 (Mol. W. 335-6). 2) At. W. 162 (Mol. W. 372). 



3) At. W. 108-8 (Mol. W. 265-6). 3) At. W. 110*3 (Mol. W. 268-6). 



4) At. W. 110-53 



(Mol. W. 269-06). 



5) At. W. 114-9 (Mol. W. 277-8). 



6) At. W. 120 (Mol. W. 288). 



