Manufacture of Soda. 121 
ee 
or localities. The process now brought forward escapes these objec- 
_ Sulphate of Soda (SO%NaO), 125 kilograms. 
- Peroxyd of Iron (Fe?0*) al ht 
_ __— Carbon, ig 
The sulphate of soda may without inconvenience contain some com- 
_ Mon salt; but then the oxyd of iron and carbon should be proportioned r 
: . J 
ace for calcination is used, taking care to break up the larger ee 
The oxyd of iron should 
should be as pure as possible. ‘ 
as e first operation, instead of the artificial or native peroxy 
mm, the carbonate (spathic iron) may be employed, or the ma 
d, or even iron filings. But in the case of the last, the quar 
hecessary ne 
+ be coke, or any other organic 
ill vary with its reducing prop- 
ary coal. : 
must be such as will combine with all 
: SFe. of the pure 
