Some unusual properties of the porous graphite contact onp‐type silicon are described. Current through the sample reaches a saturation level that is inversely proportional to the amount of adhered water vapor. Other gases such as ammonia, H2S, and HCl modify the shape or amplitude of the saturation current. There is a hysteresis loop in the low voltage region which is similar in appearance to that of a ferroelectric. The general method of measurement can be applied to studying the semiconductor surface as well as the contact phenomena. The possible applications include such devices as current regulators, humidity detectors, and surface‐barrier radiation detectors.An electronic band model, which includes a trap‐dominated inversion layer, is presented to explain the phenomena. This model also integrates various conflicting theories of metal‐semiconductor contacts.