IOWA ACADEMY OF SCIENCES. 53 



break through the film, forming metallic contact, thus 

 reducing the resistance,'' and that this takes place until a 

 bridge of metallic particles is formed of such a cross sec- 

 tion as to have a maximum carrying capacity equal to the 

 current impressed. 



Lodge* considers coherence to be of the nature of a 

 welding together of the surfaces, and has been interpreted 

 by later observers as considering the fall of potential due 

 to the formation of a metallic bridge between the particles, 

 "especially if the electric stimulus acted in any way as a 

 flux by reducing the infinitesimal tarnish of oxide or other 

 compound which must be supposed normally to cover 

 them." It would seem that this conception might be pos- 

 sible if one considered the fluxing to be electrolytic. 



*Phil. Mag. 37, p. 94; Electrician, 40, p. 87. 



