2604.     ---------------.  [PERNOUX, E.]  [Use of the Electron Microscope in the Study of Catalyst Supports.]  Jour. chim. phys., vol. 47, 1950, p. 233; Chem. Abs., vol. 44, 1950, p. 7635.

        Treatment of kieselguhr with HNO₃ and HCl caused the formation of a SiO₂ gel.  The gel was completely removed by reaction with 5% Na₂CO₃.  Alkali treatment of raw kieselguhr dissolved only the smallest particles.  The results confirmed the conclusions drawn by Teichner (abs. 3362).

        ----------.  See abs. 3363, 3363a.