2821.     RIEDEL, H. G.  [Status of Scientific Knowledge and Technical Development in the Field of Tar Processing, Extraction and Synthesis.]  Bergbau-u. Energiewirtsch., vol. 2, 1949, pp. 243-250; Chem. Zentralb., 1950, II, p. 1765.

        Subjects discussed are:  Preparation of low-temperature tars, their processing, extraction, and hydrogenation, and the Fischer-Tropsch process.