212 
ADULTERATION OF POTASSA BY SODA. 
5. 50 gr. potassa and 50 gr. anhydrous soda. 
6. 40 " 60 " 
7. 30 " 70 " 
8. 20 " SO " 
9. 10 " 90 " 
I then added water by drops to these nine mixtures, until 
the state of each of them was such that they became no 
harder, and until they were slightly pasty, and susceptible 
of being kneaded. Notwithstanding the facility with which 
this point was attained, by an unfortunate circumstance 
this operation required a very long time proportionally, for 
this object was seldom effected in less than forty-eight 
hours. It is scarcely necessary to observe that, during this 
time, I prevented as much as possible the access of atmos- 
pheric air by covering the vessel, in order not to have false 
results, by the loss of water evaporating during that time. 
It was necessary also to take care not to leave the moist- 
ened mixtures too long without looking at them, because 
otherwise it often happens that the mixture hardens to such 
a degree that it is very troublesome to divide it properly. 
After the moistened mixtures had ceased to become hard- 
er, when in a homogeneous state, and capable of being 
gently kneaded, I determined the quantity of water neces- 
sary for each mixture separately, and I found that the 
following quantities had been added : — 
Grains of Water. 
To the first mixture 1 7 
" second 40 
" third 57 
" fourth 68 
" fifth 80 
" sixth 95 
" seventh 107 
" eighth 118 
" ninth 130 
It is evident that the result answered, and that the pro- 
