126 TRANSACTIONS OF THE 
THE ELECTRON THEORY OF CONDUCTION 
OF ELECTRICITY. 
BY DR. FRANK L. WEST. 
When a salt, such as sodium chloride, is dissolved 
in water, the chlorine atom receives an electron from the 
sodium atom and separates from it becoming an ion 
(the anion) and the sodium atom, having lost a nega- 
tive charge, is left positively charged. (the cation) 
Ordinary normal solutions of the common salts dissociate 
to the extent of about 65%; i. e. two out of three mole- 
cules have broken up into ions. The more dilute the 
solution the greater the degree of dissociation. The 
strong mineral acids and bases and the strong organic 
bases dissociate to the extent of 90 to 95%, the weaker 
ones to a correspondingly less degree. The degrees of 
dissociation are determined by the amounts of abnormal- 
ity of osmotic pressure, elevation of boiling point, depres- 
sion of the freezing point, by the electrical conductivity 
at the given concentration and at infinite dilution, and 
by chemical means such as the rates of saponification 
of esters by bases and the hydrolysis of sugars by acids. 
These methods give results differing from each other by 
as much as ten per cent. The discrepancy is usually 
explained by assuming that the above mentioned ions 
have a few water molecules attached to them making a 
cluster. The molecules break apart into ions before 
the electrical force is applied. When the two electrodes 
are inserted into the solution, the positive cation migrates 
toward the negative pole and the negative anion toward 
the positive pole, in other words there is a lateral shift 
toward the electrodes and this motion is superimposed 
on their otherwise random motions. The ‘degree of 
conductivity depends on the number of ions present, their 
charge or valence, and their mobility under unit potential 
gradient. It increases with temperature even though 
there are fewer ions there because of the large increase 
in mobility due to diminished viscosity. 
The metallic conduction is usually explained by 
