• 51 TH« IDENTITT OF COLUMBIUM AND TANTALITIVI. O^ 



be softened with water, and a portion of the oxide could be 

 so dissolved; but it seemed preferable to employ dilute mu- 

 riatic acid, which by dissolvkig all the other ingredients 

 excepting columbium, left the oxide nearly white, by the 

 removal of the iron and manganese that had been combined 

 with it. 



The muriatic solution having been poured off and neu- 

 tralized with carbonate of ammonia, the iron was then sepa- 

 rated by succinate of ammonia; after which the manganese 

 was precipitated by prussiate of potash. 



The products thus obtained from five grains of col um- products «f 

 bite, after each had been heated to redness, were nearly, columbite. 



White oxide • 4 grains 



Oxide of iron | 



Oxide of manganese | 



but it cannot be supposed that proportions deduced from 

 experiments made on so small a scale can be entirely depen- 

 ded upon, although the properties of bodies may be so dis- 

 cerned, nearly as well as when larger quantities are era- 

 ployed. 



An equal weight of tantalite taken from a specimen, of Products »r 

 which the specific gravity was 7*3, yielded, by the same '*"^^''**- 

 treatment. 



White oxide .....;.. 41. grains 



Oxide of iron 1^ 



Oxide of manganese* • -j?o 



The white oxides obtained from each of these minerals T^^i"so^"'''«~ 

 gre remarkable for their insolubility in the three common oxide in mi- 

 mineral acids, as both Mr. Hatchett and Mr. Eckeberg have neial acid*. 

 observed. 



In muriatic acid they cannot be said to be absolutely in- 

 soluble; but they are not sufficiently soluble for the pur- 

 poses of analysis. 



In nitric acid they are also nearly, if not perfectly insolu- 

 ble. 



In sulphuric acid, when concentrated and boiling, the 

 oxide of columbium may be dissolved in small quasititv, ' 



and 60 also may the oxide obtained from tantalite. 



The 



