VII.—On aA DIAGRAM OF FREEZING-POINT DEPRESSIONS FOR 
ELECTROLYTES.—By Pror. J. G. MacGreaor, Dalhousie 
College, Halifax, N.S. 
(Received June 20th, 1900.) 
The object of this paper is to describe a diagrammatic method 
of taking a bird’s-eye view of such knowledge as we possess of 
the relation of the depression of the freezing-point to the state 
of ionization in aqueous solutions of electrolytes, and to show 
that such diagrammatic study gives promise of throwing much 
light upon the following questions: (1.)*—Has the depression 
constant a common value for all electrolytes, and if so, what 
is it? And (2), What is the state of association, and what the 
mode of ionization of electrolytes, in solution ? 
Construction and Properties of the Diagram. 
If an extremely dilute solution contain an electrolyte whose 
molecule, as it exists in solution, contains p equivalents, and dis- 
sociates into g free ions, and if @ is its ionization coefficient and 
k its depression constant, the equivalent depression will be: 
(1 +a («q-1)}. 
If therefore we plot a diagram of curves with ionization coeffici- 
ents as ordinates, and equivalent depressions as abscissae, the 
resulting curves must, at extreme dilution (a = 1), be tangential 
to the straight lines represented by the above equation, provided 
the proper values of hk, p, and q be employed. ‘These straight 
lines, which, for shortness, we may call the tangent lines of the 
curves, can readily be drawn in the diagram, with any assumed 
value of k, and on any admissible assumptions as to the values 
of p and q. In the diagram on page 235 the dashed lines are the 
ra) 
P 
* On this question, see also a paper recently communicated to the Royal Society 
of Canada, and to be published in its Transactions for 1900. 
(211) 
