26G Mr. Brown on the Products of the Soda Manufacture. 



phosphate of soda. The magnesia was thus separated as ammonia phos- 

 phate : — 



2MgOP0 5 MgOS0 3 

 1000 grains of sulphate of soda gave, 270 2-893 



The quantity of chloride of sodium was ascertained by precipitating the 



chlorine by nitrate of silver and nitric acid: — 



NaCl, 

 Ag CI. per 1000 grs. 



200 grains of sulphate of soda gave, 4*30 8-995 



1000 — — 29-70 12-373 



500 — 13-80 11-500 



Average, 10956 



The sulphate of soda always contains a small quantity of free acid, 



the amount of which was ascertained by determining the weight lost by 



heating to redness : — 



per 1000 grs. 

 Free Acid, 



200 grains of sulphate of soda lost, T70 8*50 



200 — — 1*84 9-20 



Average, 8*85 



Sulphate of soda, 962-170 



Sulphate of lime, 9*731 



Sulphate of magnesia, 2893 



Chloride of sodium, 10-956 



Iron peroxide, 2*300 



Sand, 3-100 



Free acid, 8850 



1000-000 

 This brings us to the consideration of the second part of the process, 

 namely, — 



II. The conversion of Sidpliate of Soda into Crude Carbonate of Soda, 

 or British Barilla. 



This is effected by the combined action of coal and carbonate of lime. 

 The following Table shows the quantities commonly used : — 



Theoretical 

 Cwt. Qrs. Per cent. quantity. 



Sulphate of soda, 2 2 100 lbs 100 lbs. 



Ground limestone, .... 2 2J 102-9 i 1053.. 



Coal dross, 1 3 61'7 ■ 33-6 * 



These, after being intimately mixed, are introduced into a reverberatory 

 furnace, and strongly heated. The mass soon becomes soft, when care 

 must be taken to stir it frequently, in order to expose a fresh surface to 

 the heat. When it becomes of the consistence of dough, the chemical 

 action commences, and jets of inflamed carbonic oxide begin to issue from 



