COLUMB1UM. 75 



water driven off as at first. The result was pre- 

 cisely the same. I have been induced to give 

 an account of the appearance of these crystals as 

 a curious fact. I did not examine them, but 

 dissolved the whole in water, expecting that it 

 would be in my power to form them at pleasure ; 

 but none of my subsequent attempts to obtain 

 similar crystals was crowned with success. 



The aqueous solution of the fused mass con- 

 tained all the alkali, and the greatest part of the 

 oxide of columbium, but not the whole. To se- 

 parate this undissolved portion, which amounted 

 only to a few grains, the liquid was passed 

 through the filter. The liquid was now decom- 

 posed by sulphuric acid, in order to obtain co- 

 lumbic acid in the state of a hydrate. This hy- 

 drate was collected on the filter, and, being well 

 washed with water, was allowed to dry in the 

 open air. 



2. Hydrated columbic acid thus obtained was 

 a white tasteless powder. When placed upon 

 litmus paper, it gave it a lively red colour ; and 

 yet I could not detect in it the presence of any 

 acid. This property had been observed by Hat- 

 chett, and induced him to consider the oxide as an 

 acid. It was soluble in sulphuric and muriatic 

 acids ; but I could not succeed in saturating 

 these acids with it, nor indeed in perceptibly di- 

 minishing their acid properties ; rand though it 

 dissolved in the vegetable acids, as Dr. Wol- 



