43 2 



Note 34: conductances of salt solutions 



number to which we may give that name is such that when any two ions are 

 actually combined into an electrolyte, the conductivity of the electrolyte 

 depends on the sum of their respective numbers.) 



Kohlrausch has also calculated the actual average velocity in millimetres 

 per second with which the components are carried through the solution under 

 an electromotive force of one volt per millimetre; and on the hypothesis that 

 the components are charged with the electricity which travels with them, he 

 has calculated the force in kilogrammes weight which must act on a milligramme 

 of the component in order to make its average velocity in the solution one 

 millimetre per second. 



It appears to me that the simplest measure of the specific conductivity of 

 an ion is the time during which we must suppose the electric force to act upon 

 it so as to generate twice its actual average velocity. If we suppose that all the 

 molecules of the ion are acted on by the electromotive force, but that each 

 of them is brought to rest by a collision with a molecule of the opposite kind 

 n times in a second, then the average velocity will be half that which the force 

 can communicate to the molecule in the n th part of a second. 



iSr 

 JCa 



Pig 

 iZn 

 lCu 



8681 



16180 



6817 



4806 



27925 

 11520 

 6180 

 14670 

 20807 



According to the theory of Clausius, it is only a small proportion, sa\ 

 of the molecules, which, at any given instant, are dissociated from molecules 

 of the other kind, so as to be free to move under the action of the electromotive 

 force, so that we must suppose each of the free molecules to continue free for 



