12 A relation between velocity and volume of organic ions, etc. 
Discussion of Table. 
The last three columns of the table show that the velocity of 
the ion of a member of a homologous series of the organic bases 
examined varies inversely as the cube root of its ionic volume, for 
the product of these is sensibly constant. The mean value of the 
product va for the 22 ammonium ions is 20'2, for the 7 homologues 
of aniline 18 - 8, for the 13 homologues of pyridine and quinoline 
20 - 3, for the 5 phosphonium ions 17 *6, for the 2 arsonium ions 193, 
for the 2 stibonium ions 180, and for coniine and menthylamine 
16-5. 
Including this paper and the last paper we have calculated the 
value of the product va for some 80 substances. 
Conclusions. 
1. The value of the product ionic velocity into the ionic 
linear dimension, or va, has been calculated for the cations of 49 
organic bases in aqueous solution. The ionic volumes, of which 
the ionic linear dimension is the cube root, have been found from 
molecular and atomic volumes. It is found that for the ions of a 
given series of the organic bases investigated, amines, homologues 
of aniline, homologues of pyridine and quinoline, phosphines, 
arsines, and stibines, this product va is constant. 
2. It has been shown that these results may be accounted for 
by considering the motion of an ion through an electrolyte as 
similar to that of a small body through a viscous medium, for 
under these conditions the ionic velocity, for ions of a given shape, 
would be inversely proportional to the ionic linear dimension. 
