■'30 Mr. W. Sutherland on Ionization in Solutions 



But my previous paper gave the approximate result that 

 1/Aqi varies as ?7 a 1 K 1 /V 1 , so 1/A varies as a^K^v^ and i£ we 

 use this approximation in the right-hand side of (31), it 

 becomes, on determination o£ the constants from the data in 

 the next table, the manageable equation 



1 0-0365 0-0022 , OQN 



B^A B* v(l + c'/B*) 



in which c! is a constant and B 3 stands for a. In my paper 

 on Diffusion the value of c' was found to be 220/21 = 10*5. 

 In the following table the values of A calculated by (33) are 

 compared with the experimental. The values of B are taken 

 irom my previous papers. 



Li. Na. K. Rb. Cs. Mg. Oa. Sr. Ba. 



B 2 7-4 18-6 344 56 56 8'6 10-6 166 



A exp 35-5 44-4 65'3 673 678 48 53 54 57"3 



A calc. ... 341 £0-3 61-8 67-6 69-3 47'8 54-3 57"5 650 



Zn. Cd. Ag. Pb. F. CI. Br. I. 



B 10-6 125 6-3 9-8 9 19 26 36 



A exp 47-5 525 557 57 461 65'9 675 66'7 



A calc. ... 57-5 59-0 492 56-2 53-0 G22 65"5 67'9 



This table shows that (33) gives the general connexion 

 between the volume of an ion and its ionic conductivity, but 

 not the details of the relation. The details cannot be given 

 by any formula which makes A a function of B and v only, 

 because, for example, Na and Ag have nearly the same B 

 and yet A = 44*4 and 55*7, and again, Sr and Zn with the 

 same B give A = : 54 and 47*5. But it must be remembered 

 that we are dealing with a formula which expresses the 

 effects of two distinct viscous resistances. In the case of Li 

 the term in (33) arising from induced viscosity is nearly 

 80 times that arising from ordinary viscosity, while in that of 

 Cs the first is only double the second. It is rather remark- 

 able that the ionic conductivity of Li comes out only about 

 half of that for Cs. Probably we are not entitled to super- 

 pose the ordinary viscous resistance on that of the induced 

 viscous resistance of electrical origin in (8 a) as if they did 

 not affect one another. Probably the latter makes the 

 conditions different for the former, altering the slipping and 

 otherwise interfering with the motion caused by ordinary 

 viscous resistance. Probably (8 a) and the equations derived 

 from them need to be completed by repeating the calculation 

 of Stokes with express provision for three sorts of viscosity 



