Experimental results of Professor F. T. Trouton relating to equilibrium vapor pressure and total mass of water vapor fed to glass wool that had previously been thoroughly dried, showed an interesting drop in the curve at about half saturation pressure. The character of the curve appeared to afford grounds for a theory, proposed by Trouton, which supposed the condensation to have taken place in two modes, or states, which he called the alpha and the beta states. After thorough drying, employing the three agencies of continued vacuum, phosphorus pentoxide, and a temperature of about 160°, moisture in the alpha state was supposed to condense on the dried surface first. The alpha condensation required relatively only a small amount of water
