58 URANIUM, ANTIMONY, CHROMIUM, &C. 







it renders cudbear gaper violet, however care- 

 fully washed and crystallized. When exposed 

 to the air it slowly " deliquesces ; this circum- 

 stance prevented me from being able to deter- 

 mine its water of crystallization. The salt dis- 

 solves readily in water, and the solution is trans- 

 parent and colourless. 



Action of The characters of molybdic acid being rather 

 >n imperfectly described in chemical books, I shall 

 here state the effects of the different reagents 

 upon a solution of this salt. 



1. Prussiate of potash Produces no change. 



2. Gallic acid Strikes a fine orange red, but occasions no 



precipitate. 



3. Tincture of galls Gives the same colour, and throws 



down a bulky orange red coagulum. 



4. A piece of tin, with a drop of muriatic acid Strikes a 



deep blue, and a dark blue precipitate falls. 



5. Sulphuric acid Throws down a chalk white precipitate, 



redissolved in an excess of acid. When this solution 

 is evaporated nearly to dryness, it is colourless while 

 hot; but on cooling, assumes a very beautiful blue 

 colour, which continues, though the solution be di- 

 luted with water. 



6. Nitric acid A white precipitate, redissolved by an excess 



of acid. The solution being evaporated to dryness 

 leaves a yellow crust, which becomes white on add- 

 ing water. 



7. Muriatic acid The same. The solution being evaporat- 



ed becomes green, and of a fine blue colour on add- 

 ing water. 



8. Phosphoric acid 1 A white precipitate redissolved by 



9. Arsenic acid J an excess of acid. 



