﻿Ions and the Relative Ionization-Power of Solvents. 395 



allowing weight to each in proportion to the time-interval 

 used in obtaining it, comes out 048 centim. per hour, and 

 the mean galvanometer reading 41 o, 0. 



The specific resistance of the solution was measured by 

 using a Wheatstone's bridge with alternating currents, and 

 gave 246*2 legal ohms per cubic centimetre when reduced 

 to 18° C. 



The area of cross section was determined by weighing the 

 water required to fill an observed length of the glass tube, and 

 found to be 0*430 square centim. 



The strength of the current was shown by the galvano- 

 meter-reading to be 2 7"g" ampere. Substituting these values 

 in our equation, we get for the hydrogen ion travelling 

 through a solution of sodium acetate in agar jelly whose 

 concentration is 0*07 gram equivalent per litre, when urged 

 by a potential gradient of 1 volt per centimetre, a velocity of 



0*000065 centimetre per second. 



The value given by Kohlrausch for the same ion is 0*0030 

 centim. per second, so that in acetates its speed is reduced in 

 the ratio of 1 to 46. 



The ratio of the conductivity of a solution of acetic acid of 

 the strength used above to that of a decinormal solution of 

 hydrochloric acid is 1 to 59. 



Thus the velocities of the ions are reduced in about the 

 same proportion as the conductivity, and even in such cases 

 as these the conductivity can be calculated from a knowledge 

 of the opposite ionic velocities. It appears that all the factors 

 determining the conductivity of a solution primarily act by 

 exerting an influence on the ionic velocities. These factors 

 may be (first) the " ionization," i. e. the average fractional 

 time during which an ion is on the whole active (in whatever 

 its activity may really consist) ; and (secondly) the resistance 

 offered by the solution to its motion by reason of viscosity. 



It seems probable that the " ionization " power of different 

 solvents is largely dependent on their specific inductive ca- 

 pacities. Prof. J. J. Thomson has pointed out that the effect 

 of immersing a molecule held together by electric forces in 

 a medium of high specific inductive capacity is to greatly 

 reduce the forces between the atoms. In this manner thev 

 may acquire the freedom necessary for electrolytic activitv. 

 which would, for any one salt, be proportional to the specific 

 inductive capacity of the solvent in which it was dissolved. 



If we assume that the resistance of a liquid to the passage 

 of an ion through it depends on its ordinary viscosity, we 

 ought to be able to calculate the relative conductivities of a 



