2742.     ---------------.  [PRETTRE, M.]  [Conditions for Utilizing Surface-Area Measurements by Adsorption in the Study of Adsorbents, Catalysts, and Their Constituents.]  Jour. chim. phys., vol. 47, 1950, pp. 99-103; Chem. Abs., vol. 44, 1950, p. 7615.

        Surface-area measurements by low-temperature gas adsorption are useful in studying adsorbents and catalysts. However, in comparing surface area and catalytic activity, cognizance must be taken of the many variables such as catalyst composition, temperature, time of evacuation, and nature of prior chemical treatment that may cause marked variation in the activity per unit surface area.

        ----------.  See abs. 779.