236 Proceedings of Royal Society of Edinburgh [sess. 
Thus if we translate the data for good electrolytes given in 
Table I. of Kohlrausch and Holborn’s Leitvermogen der Electrolyte 
into these units, and plot against y, straight lines are obtained 
in almost every case. 
The range within which this linear relationship holds for good 
electrolytes, that is, for strong acids, alkalis, and salts, begins at 
about 0’5 gram molecules per kilogram and extends up to the 
point of saturation in the case of salts of moderate solubility such 
as common salt. In the case of several, the very soluble salts, 
strong acids, and alkalis, the range extends from 0*5 to over 7 gram 
molecules per kilogram (T), or, expressing the concentration in the 
usual, way, from about 0‘5 to about 10 normal. 
At still higher concentration the relation between y and K 
ceases to be linear. In some cases, at any rate, this would appear 
to be due to false assumptions regarding the nature of the 
solution. This subject will be discussed in a subsequent paper 
dealing with the conductivity of the strong acids. 
Where equation (1) holds we may write 
k = ay + by 2 . 
• (2) 
This is obviously a parabola with a maximum value of k corre- 
sponding to 
a 
y= ~ W 
Tor brevity let 
-. 2 b* ym 
The maximum value of k, i.e. Km, is therefore 
O 
7 9 ^ 
aym + bym A = — . 
4 b 
We may therefore write equation (1) in the two forms 
\ = Ky~h m ) ■ ■ • ■ ( 3 )> 
or A m = 2 Jb x m + by . . . (4). 
The significance of maximum specific conductivity is reserved 
for discussion in connection with the experimental investigations 
relating to this part of the subject. Meantime it may be stated 
that whenever an electrolyte is sufficiently soluble to give a 
solution of maximum specific conductivity, the maximum falls 
