A new method of studying the surface states of silicon is described. Essentially it involves applying porous graphite contacts top‐type silicon and exposing the samples to various inversion‐layer producing gaseous ambients. A voltage pulse is applied to the sample and the resulting current pulse is a measure of the density of charge states. From such data it was found that the number of water‐vapor‐induced surface states onp‐type silicon was 5×1012/cm2. For any sample this value was reduced ∼50% by using ammonia instead of water vapor. Tests using widely differing electrode particle sizes resulted in no change in the measured density of states. By applying a small dc bias (∼1 V at <1 mA) to control the surface potential it is possible to continuously extend the current envelope or reduce it to a small capacitive spike. The total charge, at fixed bias, is a constant, independent of applied voltage amplitude.