ADULTERATION OP POTASSA BY SODA. 
203 
ART. XLVIII. — ON THE MEANS OF ASCERTAINING THE 
ADULTERATION OF POTASSA BY SODA, AND DETER- 
MINING IN A SIMPLE MANNER, THE PROPORTION OF 
THE LATTER. 
BY E. F. ANTHON, OP WEISGRUN. 
The following prize question, proposed among other 
subjects by the Societe de Pharmacie, of Paris, " to give 
an easy and commercial process for detecting the pre- 
sence and proportion of soda in the potassa of com- 
merce" induced me to undertake this work. 
In order to find a process of this nature, proper for 
determining the proportion of soda in potassa, adulterated 
by this alkali, and of giving a satisfactory result, with re- 
spect to celerity and accuracy, even in the hands of persons 
unacquainted with chemistry, it was neccessary to submit 
to a more attentive examination the processes hitherto 
employed for separating the salts of soda from those of 
potassa. 
A process ordinarily employed in analysis, and which 
presents also the necessary accuracy, is that of Berzelius ; 
it consists in converting the two alkalis into metallic chlo- 
rides, evaporating to dryness, and heating in a platinum 
crucible to the commencement of redness, and then weigh- 
ing. The saline mass thus obtained should be mixed with 
3| times its weight of crystallised chloride of platinum 
and sodium, which may also be replaced by a solution of 
chloride of platinum, to which a small quantity of chloride 
of sodium has been added. It must afterwards be dis- 
solved in very little water, evaporated almost to dryness at 
a very gentle heat, and then treated by alcohol of. 60 per 
cent. The chloride of sodium is dissolved in it as well as 
the chloride of platinum and sodium added in excess, and 
the chloride of platinum and potassium forms an insoluble 
residue, which must be washed on a filter with alcohol. 
