32 Mr. J. Brown 07i the Products of the Soda Manufacture. 



acid; it was then thrown on a filter, dried at 212° and weighed. 

 From its weight the quantity of sulphuret of sodium was cal- 

 culated. 



3. Hydrate of soda. — To ascertain the quantity of hydrate 

 of soda, a portion of the substance was heated strongly with 

 carbonate of ammonia in order to convert the hydrate and 

 sulphuret into carbonate. The amount of carbonic acid was 

 then determined as formerly, and the difference between the 

 results of the two experiments gave the amount of carbonic 

 acid equivalent to the quantity of soda existing as hydrate and 

 sulphuret in the sample. The amount united to sulphur was 

 then deducted, and the remainder gave the per-centage of hy- 

 drate. 



4. Sulphate of soda. — A portion of the salt was dissolved 

 in a pretty large quantity of water, and nitric acid added to 

 expel the carbonic acid. The sulphuric acid was then preci- 

 pitated by chloride of barium. 



5. Sulphite of soda. — The salt was boiled with strong nitric 

 acid in order to oxidize the whole of the sulphite of soda and 

 sulphuret of sodium. Water was then added, and the sul- 

 phuric acid precipitated by a salt of barytes. From the quantity 

 of sulphate of barytes thus obtained, the amount got by the 

 former experiment was deducted, and the remainder showed 

 the quantity of sulphate of barytes equivalent to the amount 

 of sulphite of soda and sulphuret of sodium. The per-centage 

 of sulphuret of sodium being known, the sulphite of soda was 

 easily determined. 



6. Chloride of sodium. — After expelling the carbonic acid 

 by nitric acid, the chlorine was precipitated by nitrate of silver. 



7. Aluminate of soda and insoluble matter.' — A solution of 

 the salt was acidified by muriatic acid, and the insoluble matter 

 (principally sand) separated by filtration. From the filtered 

 solution the alumina was precipitated by caustic ammonia. 



The salt obtained by evaporation from the liquor from the 

 keaves, after drying at 212°, yielded on analysis,- 



Carbonate of soda . . 



Hydrate of soda . . . 



Sulphate of soda . . . 



Sulphite of soda . . . 

 Hyposulphite of soda 



Sulphuret of sodium . . 

 Chloride of sodium . 



Aluminate of soda . . 



Silicate of soda . . . 



Insoluble matter . . . 



100-735 99-94.1 



