METHODS BY WHICH SODA IS PREPARED. 24J 



VI. 



Account of the Methods by which Soda is at prefent prepared for 

 the Englijh Market ; with other Obfervations. By Mr. Fred. 

 Accum. From the Author. 



UlNCE the late new duty on fait, the manufacturers of foda Soda obtained by 

 avail themfelves of the method of decompofing the fulphate of fu^^o? the 

 foda *, by means of what is called American potafh. Though bleachers with 

 this kind of potafh contains lefs pure alkali than the Ruffian f^ erican pot " 

 or German potafh, it is imported in a Irate of perfect dry- 

 nefs, whereas the other is always met with in a moift flate ; 

 fo that the ab fence of water appears to compenfate for the 

 deficiency of the alkali. The American potafh fells now from 

 48s. to 54s. per cwt. it has been confiderably higher, until 

 lately it fluctuated between 54s. and 56s. 



I have been employed in a foda manufactory in which the Particular de- 

 following method anfwered exceedingly well. ' Five hundred mlnuheL\xx\nz 

 pounds of fulphate of foda were introduced into an iron boiler procefs. 

 containing a fufficient quantity of Thames water. 560 lb. of 

 American potafh were likewife diffolved in as little water as 

 poffible in an iron boiler fixed near the former. The potafh 

 was always previoufly tried, and if indifferent the quantity 

 taken was 10 lb. more. 



The folution, as near as I recollect, was made with about A boiling folu- 

 thirty pails of water to the alkali here mentioned. Both folu- tl0n of P° tafll 



. . i,t-i i r i i it- • was added to ac- 



tions were then made to boil, and as loon as the ebullition other of fulphate 



took place the folution of potafh was ladled into the boiler o{ foda » 



containing the fulphate of foda. The mixture was agitated 



during the transfufion, and the fire raifed as expeditioufly as 



poffible. As foon as the fluid boiled it was ladled into a then boiled, 



wooden gutter, which conveyed it into a cittern of wood lined 



with fheet lead nearly half an inch thick, which was fixed in 



a cool place. Sticks of wood were then placed acrofs the 



ciftern, from which flips of fheet lead two or three inches 



wide were hung into the fluid at four inches diftant from each 



* Sulphate of foda is fold cheap by the bleachers, who have it as 

 the refidue of decompofing common fait by fulphuric acid with 

 manganefe. In February, 1801, it was worth from lis. to 14s. 

 per cwt. but I have not the prefent price.-— A. 



Vol. II.— -August, 1802. R other. 



