SOLUTIONS.—MACGREGOR. 75 
As a, N, anda, N, are the numbers of gramme-equivalents of 
dissociated molecules of (1) and (2) respectively in unit volume 
of the solution, and as u,,, and “,,5, 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, N, u,./a, N, #4 
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 z, we have: 
I ’ 
N, a (VE L) 
' ka 
5 NT ee 2) 
The values of the ionization coefficients obtained in this way 
a, = 
as 
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 may be tested by 
being compared with the values given by the method described 
above. For the values given by this method have stood the test 
of application to the calculation of the conductivity’, results of 
1 MacGregor: Trans. N.S Inst. Sci., 9, 101, 1895-6. 
McIntosh: Jbid. 9, 120, 1895-96. 
Archibald: Jbid. 9, 291 and 307, 1897-98; and Trans. Roy. Soc.Can., (2), 3, sec. 3, 
69, 1897-98. 
McKay: Trans. N. S.Inst. Sci., 9, 321 and 348, 1897-98. 
Barnes: [bid., 10,49, 1898-99. 
