DEPRESSIONS FOR ELECTROLYTES—MACGREGOR. 213 
Owing to ionization, the curve of an electrolyve will differ 
from that of a non-electrolyte, (1) because of the change thereby 
produced in the number of molecules (including free ions) in unit 
of volume, and (2) because of the change produced in the dis- 
turbing influences referred to. The former change is doubtless 
the more important, and I shall assume the latter to be negligible 
for the present purpose. Now dissociation increases continu- 
ously with dilution. If, therefore, association of molecules does 
not occur, and if the mode of ionization does not change, the 
equivalent depression must be increased by the dissociation, in a 
ratio which increases continuously with dilution. The change 
produced in the curve by dissociation, therefore, will be a shear 
parallel to the equivalent depression axis, and increasing with 
dilution. The resulting curve will consequently remain convex 
towards the axis of dilution, but it will be less likely than the 
curve of a non-electrolyte, to exhibit the minimum point. 
It, now, we plot equivalent depression against ionization 
coeticient, instead of dilution, the result will be the same as if 
we shortened the dilution ordinates of the various points of the 
curve just mentioned, in ratios increasing with the dilution, 
which process must leave the curve convex towards what was 
the dilution axis, but is now the ionization coefficient axis. 
If, therefore, no change occur in the association of molecules 
or in the mode of ionization, the curve of an electrolyte on the 
diagram must start at the intersection of its tangent line, tangen- 
tially to that line, and bend away from it, as dilution diminishes, 
to the right, possibly passing through a point of minimum 
equivalent depression. We may speak of such a curve as the 
normal curve for the tangent line, corresponding to the given 
conditions as to constitution in solution, and mode of ionization. 
If, the constitution of the electrolyte in the solution remaining 
constant, the mode of ionization changes as dilution diminishes, 
say, in such a way that the molecules dissociate, on the average, 
into a smaller number of ions, the equivalent depression will 
diminish more rapidly than it otherwise would. The curvature 
of the curve will therefore diminish, and may possibly become 
