SOLUTIONS. MACGREGOR. 75 



As a l Nj and a 2 N 2 are the numbers of gramme-equivalents of 

 dissociated molecules of (1) and (2) respectively in unit volume 

 of the solution, and as i^ aol and ^3, the respective equivalent con- 

 ductivities at infinite dilution, of simple solutions of 1 and 2, 

 may in sufficiently dilute solutions, whether simple or complex, 

 be regarded as equal to the velocity of either ion, relative to the 

 other, of 1 and 2 respectively, the quantity a 2 N 2 p w2 / a l Nj p ool 

 may be taken to be the ratio of the number of gramme-ions of 

 2 and 1 separating out primarily at the appropriate electrode, 

 during electrolysis. This ratio Schrader determined by electro- 

 lytic observations. Calling it x, we have : 



k 



a, = 



kx 



The values of the ionization coefficients obtained in this way 

 are affected not only by the error involved in the measurement 

 of conductivity, but by the more serious error involved in elec- 

 trolytic determinations. They cannot be expected therefore to 

 have any high degree of precision. 



While Schrader determined the ionization coefficients for 

 solutions containing potassium chloride and iodide, and hydro- 

 gen and copper sulphates, and drew certain conclusions from 

 their relative magnitudes in each case, he made no attempt to 

 test the values obtained. They cannot of course be tested by 

 applying them to the calculation of the conductivity of the 

 solutions or the results of their electrolysis ; for these have been 

 used as data in their determination. But they mny be tested by 

 being compared with the values given \>y the method described 

 above. For the values given by this method have stood the test 

 of application to the calculation of the conductivity 1 , results of 



1 MacGrcgor: Trans. N. S Inst. Sci., 9, 101, 1895-6. 

 Mclntosh : Ibid. 9, 120, 1895-96. 

 Archibald: Ibid. 9, 291 and 307, 1897-9S; and Trans. Roy. Soc.Can., (2), 3, sec. 3, 



69, 1897-98. 



McKay: Trans. N. S.Inst. Sci., 9, 321 and 343, 1897-98. 

 Barnes : Ibid., 10,49, 1898-99. 



