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



Had any undecom posed coal existed in the waste, it would 

 have contained hydrogen, and water would consequently have 

 been formed, the oxygen being derived from the chromic acid 

 of the chromate of lead. 



As might be expected, I found upon trying samples taken 

 from different furnaces, that the constituents were subject to 

 great variations. Thus the lime varied from 27 per cent, to 

 34 per cent. ; the soda from 22 per cent, to 26'5 per cent. ; the 

 sulphur from 10 per cent, to 16 per cent. But they always 

 stood in a certain fixed relation to one another ; for when the 

 quantity of lime was large the amount of sulphur was propor- 

 tionally increased, and the per-centage of soda consequently 

 diminished. The following table will suffice to show this : — 



I. II. III. 



Soda . . . 26-480 22-000 24-138 



Lime . . . 26-959 33-807 30-324 



Sulphur . . 10-527 13-820 12-436 



I insert here two analyses of soda balls ; the one from Cassel 

 by Unger, the other from Newcastle by Richardson. They 

 both get hydrate of soda and carbonate of lime, and are, I 

 think, wrong in both of these, although the other parts of the 

 analysis are probably quite correct. 



The manufacture in Cassel and Newcastle is carried on 

 almost exactly in the same way as here. 



From Cassel. From Newcastle. 



99-78 100-00 



III. This brings us to the consideration of the third division 

 of the soda process, viz. the manufacture of soda-ash from 

 hall soda. 



The first point is to extract all the soluble matter from the 

 balls. This is done by digestion in warm water. The vessels 

 used for this purpose are large square iron pans, five or six of 



