The possibility of using hydrated salts supported on carrier beds for extracting water from cool night air and solar energy for recovering the moisture for use as drinking water is dealt with. Equipment for obtaining sorption data in the laboratory is described. The rate of water adsorption by salts from air is a linear function of relative humidity, the amount adsorbed depending on the partial pressure of water exerted by the hydrated salt or by the aqueous salt that results on exposure to the moist air. To assure maximum adsorption it is important to select salts whose saturated aqueous solution exhibits minimal aqueous tension. Hydrated salts supported on carriers, composed of as widely different materials as porous glass, sand, and fibrous board, all release water equally well on heating, despite their large differences in physical makeup.