152 



Conductivities and Viscosities in Pure and in Mixed Solvents. 



This differs from the usual method, in that the magnesium ammonium 

 phosphate is precipitated in a hot solution, by the slow addition of 

 ammonia to an acid solution of the phosphate, to which an excess of 

 "magnesia mixture" had been previously added. A very pure, 

 coarsely crystalline precipitate, which settles readily, is obtained by this 

 method. From the weight of the magnesium pyrophosphate yielded 

 by this precipitate on ignition, the strength of the solution of the sodium 

 salt was calculated. (See table 82.) 



TABLE 81. Sodium pyrophosphate. 



TABLE 82. Trisodium phosphate. 



TABLE 83. Sodium dihydrogen phosphate. 



