4 ROYAL SOCIETY OF CANADA 
The observations which I shall use were made in my laboratory by 
Mr. E. H. Archibald’ and Mr. J. Barnes,’ by the former on solutions of 
potassium and sodium sulphates, and by the latter on solutions of 
potassium and sodium chlorides and of hydrochloric and sulphuric acids. 
Both experimenters determined the equivalent conductivity of their 
solutions at infinite dilution and at 0° C., in order that they might be able 
to find the ionization coefficients at that temperature; for which purpose 
they measured the conductivity at 18° and at 0° for series of solutions 
down to dilutions at which the ratio of these conductivities became 
constant. On the assumption that this constancy would continue, it was 
thus possible to calculate the equivalent conductivity at infinite dilution 
at 0° from its known value, as determined by Kohlrausch, at 18°. 
Both experimenters also made measurements of the depression of the 
freezing-point on series of simple solutions at moderate dilution and on 
solutions formed by mixing the simple solutions, while in order that 
they might be able to determine the state of ionization both of the simple 
solutions and of the mixtures, they measured also the conductivity of the 
simple solutions at 0°. 
The conductivity observations were made by means of Kohlrausch’s 
well known telephonic method, and the freezing-point observations 
by somewhat modified forms of Loomis’s method. The ionization 
coefficients of the simple solutions were taken to be equal to the ratio of 
the equivalent conductivity at 0° to the equivalent conductivity at 
infinite dilution at 0°. The coefficients for the electrolytes in the 
mixtures were determined in Mr. Archibald’s case by the method 
described by me in a former paper,? and in Mr. Barnes’s case, by a 
modification of that method devised by him { to render the method more 
easily applicable in cases in which but few observations of conductivity 
might be available. For a detailed account of their use of these methods, 
and of the precautions taken to secure sufficiently pure materials and to 
minimize the errors of observation, I must reter to their papers cited 
above. But I may say that although they are young experimenters and 
did not enjoy the resources of a well-equipped laboratory, those of their 
observations which had already been made by Kohlrausch, Loomis, Jones 
and others, agreed remarkably well with the observations of these 
experienced workers in this field; and that consequently we may build 
upon their observations with a great deal of confidence. 

1Trans. N.S. Inst. Sci., 10, 33, 1898-9. 
2 Ibid., 10, 139, 1899-1900; see also a paper to be communicated to the Royal 
Society of Canada at the present meeting. 
3 Trans. Roy. Soc. Can. (2), 2, sec. 3, 65, 1896-97. 
4Trans. N.S. Inst. Sci., 10, 113, 1899-1900. 
