Swallow.] 



426 



[February IT, 







-00 



it 



6 is 

 *I3 









If 



fe3^ 



-8 







."§,53 



>*s . 



e | 













The metallic acids of the Tantalic 











Group 





54.96 



54.81 



56.36 



Oxide of Tin 



SnO, 

 UO 



.16 







Oxide of Uranium 



9.91 



U0 3 17.03 



16.63 



Oxide of Iron 



FeO 



14.02 



14.07 



8.87 



Oxide of Manganese .... 



MnO 



.91 





1.20 



Oxide of Cerium (La, Di) 



CeO 



5.17 



3.95 



2.85 



Yttria 



YO 



12.84 



11.11 



13.29 



Magnesia 



MgO 



.52 





.50 



Insoluble residue from the oxalate of 











Cerium 





1.25 







Loss on ignition 





.661 



.24 



.33 





100.40 



101.21 



100.03 



The quantity at hand was too small to warrant an attempt at 

 separating the metallic acids of the tantalic group. It is to be hoped 

 that enough may be found to enable some one this side the Atlantic 

 to undertake the investigation. Hermann yet maintains the existence 

 of Ilmenium in Samarskite, Aeschynite and the Columbite from 

 Haddam, Conn. (See Journal fur Prakt. Chemie. 1870). 



The final analysis was made by the method detailed below, which 

 is essentially that of Hermann, with the omission of the tests which 

 gave negative results in the preliminary examination and with addi- 

 tion of such precautions and modifications as could be gathered from 

 the methods of separation given under the different elements in Gra- 

 ham-Otto's Chemie, and Rose's Analyse Quantitative, and the ex- 

 perience of the preceding tests. The weighed portion was fused with 

 an excess of bisulphate of potash, treated with 400 c.c. distilled water 

 and allowed to remain forty-eight hours, as the fused mass is very 

 slowly decomposed. The solution (and residue) was then heated to 

 about 90° C. and after half an hour the columbic acid was allowed to 

 settle out and was filtered off and well washed with warm water. It 

 was treated on the filter with warm sulphide of ammonium to dissolve 

 the tin. The solution so obtained was evaporated and ignited in a 

 platinum crucible, again ignited with chloride of ammonium and the 

 tin calculated from the loss. 



The columbic acid was slightly blackened by the sulphide of 

 ammonium and was consequently digested with very dilute chlor- 



1 Determined on another sample. 



