84 ON THE BLUE PHOSPHATE 



this mineral is in the minimum state of oxidation, the 

 difference being eight per cent, the real quantity con- 

 tained in it will be 2.227 grammes of Protoxide. 



C. To the liquor, from which the oxide of iron 

 had been separated, nitric acid in excess was added, 

 and boiled to expel the carbonic acid that might have 

 united with the potash during its fusion, &c. Am- 

 monia Was then added in excess which gave a slight 

 precipitate having the appearance of alumine. It 

 weighed, after calcination, 0.02 gramme 



D. The above liquor by the addition of muriate 

 of lime gave an abundant precipitate of phosphate of 

 lime which separated as usual by filtering and being 

 calcined weighed 2.00 grammes. 



E. Supposing that the ammonia in the liquor A 

 had decomposed a part of the phosphate of iron, it 

 was examined as in C and D ; thus treated it gave 

 0.21 gramme of phosphate of lime, making together 

 2.81 grammes ; as this salt is composed of M parts 

 of base, and 46 parts of acid, the quantity of phos- 

 phoric acid will be 1.S926 grammes. 



F. To ascertain the quantity of water contained 

 in this mineral, 5 Grammes were dissolved in nitric 

 acid evaporated to dryness, and calcined to expel all 

 the nitric acid. This was repeated a second time, to 

 be certain that all the protoxide of iron was converted 



