468 Proceedings of the Poyal Society of Edinburgh. [Sess. 
the curves in figs. 1 and 2 do not give any indication that it would 
occur at any other concentration. 
It should he explained that the small range of solutions of tetra-methyl 
ammonium iodide examined was due to its slight solubility in water. 
Temperature 35’ C. 
Fig. 2. 
From the present point of view, however, it was not worth while to 
investigate solutions of the chloride which is much more soluble. 
It is remarkable how slight the influence of the anion is. The particular 
salts used were chosen so as to afford some information on this point, 
without impairing their value as tests for the influence of the volume of 
