This paper was partly inspired by an experimental study of
adsorption of water in graphitized carbon black by Easton and
Machin.1 Some of their adsorption/desorption data is illustrated
in Figure 1. A striking feature of this data is the continuation of
the adsorption isotherm to supersaturated states of water vapor,
up to the point where capillary condensation of water takes place
in the spaces between the primary particles of the carbon black.