Mk Baowi * tfc !',■■ incts of the Soda Mwmfmti 



Carbonate of lime, 19*56 



3CaS + CaO, 32-80 



Carbon, 2-60 



Silicate of magnesia, 6*91 



Sand, 309 



Iron peroxide, 3*70 



Sulphate of lime, 3*69 



Hyposulphite of lime, 4*12 



Hydrate of lime, 11*79 



Bisulphuret of calcium, 4*67 



Sulphuret of calcium, 3*25 



Sulphuret of sodium, 1*78 



Water, 3*45 



100*31 



The soda waste thus affords ample room for further researches, which, 

 if carefully prosecuted, might yield very interesting results. But without 

 dwelling any longer on this subject, I pass on to the consideration of the 

 remaining part of this division of the process, viz., the manufacture of soda 

 ash from the liquor containing the soluble matter extracted from the ball 

 soda. 



This liquor contains carbonate of soda, caustic soda, sulphuret of sodium, 

 sulphate of soda, and chloride of sodium, with a little aluminate of soda, 

 the greater part of which is, however, soon decomposed by the action of 

 the carbonic acid of the atmosphere, carbonate of soda being formed 

 whilst the alumina precipitates. This solution is boiled down in an iron 

 pan until it is nearly dry. The analyses of this and the remaining salts 

 were made in the following way : — 



1. Carbonate of soda. 



The amount of carbonate of soda was determined by ascertaining the 

 weight of the carbonic acid, which was evolved on the addition of muriatic 

 or sulphuric acid to the salt. 



2. Sulphuret of sodium. 



The amount of sulphuret of sodium was ascertained by passing 

 the gases evolved on the addition of muriatic acid to the salt through 

 a solution of arsenious acid in caustic potash. The sulphuret of 

 arsenic thus formed, was precipitated by neutralising the potash 

 with nitric 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 



