SECTION ITI, 1916 [65] MRANS- RASC: 
The Double Salts formed by Sodium and Potassium Carbonates. 
By J. W: Bain, F.R.S: Ge and C. E: OLiver 
(Read May Meeting, 1916) 
The present scarcity of potassium salts has stimulated their 
production from sources which had either been abandoned, or only 
worked in a desultory fashion. The ash of seaweeds, the residues 
from the sugar factory and wood ashes were valuable materials fifty 
years ago because of their potash contents, and the interruption of 
the supply from Germany has brought them into the market once 
more in appreciable quantities. 
The methods of purifying the crude potassium chloride and 
sulphate found at Stassfurt have been worked out very exhaustively 
by van’t Hoff and others, but similar information regarding the purifi- 
cation of potassium carbonate has never been Published. The reason 
for this is, undoubtedly, that the carbonate has been manufactured 
entirely from the chloride in Germany and France, and no potassium 
carbonate has been refined elsewhere. Under the present circum- 
stances when it is desired to produce the refined carbonate in Canada 
and the United States from such sources as wood ashes, data regarding 
the behaviour of solutions of the salts of sodium and potassium are 
essential. The information available is fragmentary and unsatis- 
factory so that a study of the subject was undertaken. 
Before the investigation had progressed very far it was found that 
the separation of sodium and potassium carbonate offered difficulties 
which proved to be the result of the formation of a double salt. The 
latter, which has the formula K2CO;3, NazCO3, 12H20, has been 
described by Marguerite,! Marignac,? Fehling Stolba,t Kremann® 
and Osaka.f With the exception of Osaka who determined the solubility 
at 10° and 25° C., these authors describe the preparation, composition 
and crystal habit of the double salt; none investigated the range of its 
existence. To supply this gap the transition point was determined 
1 Ann. chim. phys. 56, 220, (1845). 
2 Compt. rend. 45, 650, (1857). 
3 Annalen, 130, 247, (1864). 
4J. prak. Chem. 94, 406, (1865). 
5 Monatsh. 30, 323. 
§ Mem. Coll. Sc. Kyoto 3, 58. 
