CONTAINING AMMONIA. 



I atom phosphate of soda 7'5 



1 atom phosphate of ammonia 5-625 

 16 atoms water . 18 



31-125 



13. Ammonio-phosphate of magnesia. 

 salt occasionally crystallizes in stale urine. In 

 such cases it is transparent and colourless, and 

 composed of four-sided rectangular prisms with 

 bases which I believe- to be squares. It is formed, 

 likewise, when a soluble phosphate and an am- 

 moniacal salt are added to sulphate of magnesia. 

 It precipitates in the state of a white powder ; 

 it is tasteless and insoluble in water. When this 

 powder is dried in the open air I find it com- 

 posed of 



1 atom phosphate of magnesia 6 



1 atom phosphate of ammonia 5*625 



4 atoms water . . 4-5 



16-125 



The water exceeds 4 atoms by a quantity which 

 varies from i to 2 atom. This excess is doubt- 

 less hygrometrical water. 



It would appear, from a set of experiments by 

 M. RifTault, that another salt composed of the 

 same acid and bases is occasionally obtained, con- 

 taining only half the phosphoric acid in the pre- 

 ceding salt. He states the composition of the 

 salt which he analyzed as follows: 



