168 On the A state of Columbic Acid. 



ing a precipitate, but when by evaporation it arrives at a certain 

 concentration, it deposits a white precipitate, which dissolves 

 anew by the addition of a large quantity of water. It would ap- 

 pear that this sublimate contains columbic acid, in a different 

 modification from that of the ordinary chlorides of columbium. 

 This modification corresponds to the two different modifications 

 of oxide of tin. Sulphuric acid precipitates columbic acid from 

 the solution, even when it is found under this modification." 

 These observations of M. Wohler, I deem of much importance, 

 to those engaged in analytical inquiries. The most trustworthy 

 of the indications of the existence of titanic acid, in a solution, is 

 the production of a blue color and precipitate by zinc. The de- 

 velopment of a yellow color by heat, has been considered a dis- 

 tinctive property of titanic acid. The compounds of columbic 

 acid have been considered insoluble in hydrochloric acid. 



If we treat pyrochlore with pure hydrochloric acid, it readily 

 dissolves, although from 50 to 80 parts per cent, of its weight are 

 columbic acid. By evaporation, the solution becomes turbid, af- 

 terwards milky, and finally deposits a white opake salt, precisely 

 as follows from the same treatment of a solution of a titanate. 

 If the evaporation has been carried on at a moderate temperature, 

 the salt is crystalline in appearance and remains soluble. Boiling 

 the solution, causes the precipitate to become nearly insoluble in 

 water, but the addition of hydrochloric acid effects a solution. 

 When the salt has been dried, it loses its opake appearance, and 

 becomes a transparent glass-like mass. Water acidulated with 

 hydrochloric acid, readily dissolves the salt. Instead of pyro- 

 chlore, we may use pure columbic acid, which has not been 

 heated, and a solution of titanic acid, or oxide of uranium, in hy- 

 drochloric acid. The hydrate of columbic acid dissolves freely, 

 if it be mixed with either oxide of uranium, or titanic acid. In 

 such a solution, it has assumed what may be called its A state. 

 Ordinary columbic acid dissolves in acids and oxalates, to a cer- 

 tain extent, but such solutions have not the characters that those 

 of the acid in its A state exhibit. From an electro-negative or 

 acid state, and without any apparent change of composition, it 

 takes a positive or basic state. It may be precipitated by carbo- 

 nates of soda and potash ; by pure and carbonate of ammonia, as 

 a white hydrate, closely resembling alumina. This hydrate dis- 

 solves in most of the acids freely. A solution in hydrochloric 



