Mr. J. Brown on the Products of the Soda Manufacture. SI 



series of analyses of the waste in its different stages of decom- 

 position, upon which perfect dependence could be placed ; 

 but it is to be hoped that as the science advances these at pre- 

 sent insuperable obstacles may be entirely removed. 



The following is an analysis by Unger of a sample of waste 

 from Cassel. 



100-31 

 The soda waste thus affords ample room for further re- 

 searches, which if carefully prosecuted might yield very inter- 

 esting results. But without dwelling any longer on this sub- 

 ject, 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, sul- 

 phuret 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. 



Analysis of Soda-ash. 

 The analysis 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 so- 

 dium was ascertained by passing the gases, evolved on the 

 addition of muriatic acid to the salt, through a solution of ar- 

 seniousacid in caustic potash. The sulphuret of arsenic thus 

 formed was precipitated by neutralizing the potash with nitric 



