344 
MANUFACTURE OF BICARBONATE OF SODA. 
No. 1. 
No. 2. 
Potash . . . 
28.52 
28.57 
Lime 
16.99 
16.96 
Sulphuric acid . 
48.94 
48.55 
Water . . . 
5.51 
5.67 
99.96 
99.75 
The purchasers of crude sulphate of potash will he much obliged 
to Mr. Phillips for this communication. 
Manufacture of Bicarbonate of Soda. — In our notice of the 
process employed in the manufacture of tartaric acid, we men- 
tioned that whiting or carbonate of lime was employed for the 
purpose of taking up the free acid in the bitartrate of potash, this 
action being attended with a copious evolution of carbonic acid 
gas; the carbonic acid so liberated, is employed in the manufac- 
ture of bicarbonate of soda. For this purpose, a series of two or 
more square air-tight wooden vessels, lined with lead, and fitted 
with a perforated false bottom placed about one foot from the low- 
est part of the vessel, are rilled with crystals of carbonate of soda 
(the common commercial soda,) and connection established between 
them by means of leaden pipes. Into the first vessel of the series, 
the carbonic acid gas, previously passed through water, is intro- 
duced, and after a few days the crystals of soda will be found to 
be converted into bicarbonate, which is then removed, dried, and 
having been ground to the requisite degree of fineness, packed in 
casks for sale. Ten cwt. of crystals of soda yield upwards of five 
cwt. of bicarbonate. The water of crystallization contained in the 
crystals of the bicarbonate,' passes through the perforated division 
with the lower compartment of the vessel, whence it is drawn off 
by means of a cock placed for that purpose, and as it contains a cer- 
tain portion of soda, it is used in the manufacture of Rochelle salt, 
which we shall presently describe, or for any other purpose requir- 
ing a solution of soda. 
It will be obvious, that carbonic acid gas from any other source 
will do equally as well for the manufacturer of bicarbonate of soda 
as that obtained as above described. 
