124 ON THE VISCOSITY 



Determination of Ionization Coefficients in the Mixture. 



The method proposed by 1 Prof. MacGregor for finding the 

 ionization coefficients in a mixture of two electrolytes having an 

 ion in common, is by solving graphically the following equa- 

 tions : 



fl -- ^ / 4 N 



V l V 3 



' 



where the electrolytes are denoted by 1 and 2, the concentra- 

 tions (in gramme-equivalents per litre) of the mixture with 

 respect to them by N t and N 2 respectively, their ionization 

 coefficients by a l and a n , and their regional dilutions (in litres 

 per gramme equivalent) by V l and V 2 , the regional dilutions 

 being the dilutions of the electrolytes in the regions which they 

 are supposed to occupy in the mixture, or the dilutions of the 

 constituent isohydric solutions. 



His graphical mode of solving these equations involves the 

 drawing of dilution-ionic-concentration curves, which, as they 

 have great curvature for moderately dilute solutions, cannot be 

 drawn with great accuracy unless a large number of observa- 

 tions of the conductivity are available. As mentioned above, 

 extensive series of observations of the conductivity in the case 

 of the salts under consideration were available ; but they were 

 all made at 18 C. and required therefore to be reduced to 25 C. 

 before they could be used. In order to reduce this labour as 

 much as possible I devised another mode of solution which 

 requires only a comparatively small number of observations. It 

 is based on the fact that ihe specific-conductivity-concentration 



1 Trans. N. S. Inst. Sci., 9, 101, 1895-96; also 10, 68, 1898-99. 



