Abstract
Anodic films contain many flaws which for thick films are the sites of electrolytic rectification. For 
and 
films below 1000Aå in thickness, however, bulk conduction also occurs. For such films the capacitance also increases markedly on polarization in the forward direction (base metal negative). One interpretation of the capacitance changes involves a proton space charge in the film. The relationship between capacitance change and current flow is examined in some detail, and it is shown that there is not a good correlation between the two effects; it therefore appears that two separate phenomena are involved. Possible interpretations are discussed.