396 
Proceedings of the Poyal Society of Edinburgh. [Sess. 
in the potassium iodide-water-alcohol cell, is not when both solutions 
are saturated with the salt, but is, when the strength of the water solution 
is such, that, when in contact with alcohol saturated with potassium iodide, 
diffusion produces no salt precipitation. This equilibrium is reached when 
the strength of the water solution is about 2 molecules of potassium iodide 
per 1000 cc. 
In conclusion, I must thank Mr Andrew King and Mr Ernest Gibson 
for their assistance, and the Carnegie Trust for the grant which enabled 
me to carry out these experiments. 
(. Issued separately April 25, 1911 .) 
