MIXTURES OF ELECTROLYTES.—MgINTOSH. 133 
small magnitude and shew such alternation of sign as to war- 
rant the conclusion that they are due chiefly to accidental 
errors. In the two series of stronger solutions the differences are 
more irregular in magnitude and the alternation of sign is much 
less marked, the most of the differences being positive. The 
above results, therefore, seem to shew that even in the case 
of two electrolytes with a common ion, which differ so markedly 
in ionic velocity from one another as sodium chloride and 
hydrochloric acid, the dissociation theory enables us to calculate 
the conductivity of solutions containing both, within the limits of 
experimental error, up to a mean concentration of about 1 
gramme-molecule per litre, and that in the case of solutions of 
greater mean concentration, the calculated value is greater than 
the observed. 
