[HENRY] CONTACT RESISTANCE BETWEEN CONDUCTORS 143 
These curves giving the relation between resistance and speeds 
show conclusively that the contact resistance increases in proportion 
to the speed. It is thus seen that a continuous flow of electrons at 
the contact point is maintained with greater difficulty than when the 
contacts are stationary. An examination of the curves shows that the 
contact resistance is inversely proportional to the pressure applied; 
this might also be expected from the standpoint that when the con- 
tacts are moving relatively to each other the electrons have smaller 
opportunity of breaking down the intervening film, and hence a greater 
pressure is necessary to overcome the resistance of the film. 
