3946.  WINKLER, F. (I. G. Farbenindustrie A. G.). [Active Carbon.] German Patent 463,772, July 19, 1928. Chem. Abs., vol. 22, 1928, p. 4212.

Active C is prepared by action of hot gases on carbonaceous materials in a blast furnace.

See abs. 569, 570, 571, 572, 573, 574, 575, 808, 809, 2055, 2056, 2057.