24,3 Dr. Wollaston on the Identity 
readily acted upon by potash; but as the iron contained in 
them is not affected by alkalies, it appeared better to add a 
small proportion of borax. 
Five grains of columbite being mixed with twenty-five 
grains of carbonate of potash and ten grains of borax, were 
fused together for a few minutes, and found to be perfectly 
incorporated. The colour was of a deep green, from the 
quantity of manganese present. The mass when cold could 
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 dissolving all other ingredients excepting 
coiumbium, left the oxide nearly white, by the removal of 
iron and manganese that been combined with it. 
The muriatic solution having been poured off and neutral- 
ized with carbonate of ammonia, the iron was then separated 
by succinate of ammonia ; after which the manganese was 
precipitated by prussiate of potash. 
The products thus obtained from five grains of columbite* 
after each had been heated to redness, were nearly, 
White oxide - 4 grains 
Oxide of iron - ~ 
Oxide of maganese 
but it cannot be supposed that proportions deduced from expe- 
riments made on so small a scale can be entirely depended 
upon, although the properties of bodies may be so discerned, 
nearly as well as when larger quantities are employed. 
An equal weight of tantalite taken from a specimen, of 
which the specific gravity of 7,8, yielded, by the same treat- 
ment. 
