OF SODA. 



and 1 atom of base. 135-5 parts of the salt, when 

 heated to redness, lose, according to Mitcher- 

 lich, 35-5 parts of water ; this is equivalent to 

 3i atoms. Hence, the constituents of the salt 

 are 



2 atoms phosphoric acid 7 

 1 atom soda . . 4 



3% atoms water . 3*9375 



14-9375 



It remains to be seen whether the half atom of 

 water be not mechanically lodged between the 

 plates of the crystals. 



9. Arseniate of soda. This salt is obtained 

 with great ease in large crystals ; because it is 

 much more soluble in hot than in cold water. 

 Mitcherlich has shown that the crystals have the 

 same form as those of phosphate of soda : when 

 exposed to the air the salt speedily effervesces on 

 the surfaces, but does not fall to powder ; when 

 heated it undergoes the watery fusion. 100 

 parts of water at 47 dissolve 22*268 parts of this 

 salt. 



I obtained this salt by mixing solutions of 

 7-75 parts of arsenic acid and 18 of crystallized 

 carbonate of soda. The salt formed was neutral, 

 and the liquid yielded crystals to the very last 

 drop. 20*75 grains of the crystals, when heated, 

 lose 9 grains of water, equivalent to 8 atoms. 

 Hence, the constituents of the salt are obviously 



VOL. II. S 



