924.    FIELDNER, A. C., AND GOTTLIEB, S.  Thirteenth Annual Report of Research and Technologic Work on Coal, Fiscal Year 1948. Bureau of Mines Inf. Circ. 7518, 1949, 87 pp.

      Summary of papers already published.  The following subjects are noted:  Electron-diffraction and electron-microscope studies of Fischer-Tropsch catalysts (p. 13); underground gasification of coal (pp. 71-73); production and purification of synthesis gas (pp. 73-76) and 4 diagrams; synthesis of liquid fuels from H₂ and CO, Oxo process, process mechanism, catalysts, internally cooled process (pp. 76-82); hydrogenation of coal, function of solvents and catalysts, Sn catalyst, hydrogenation of asphalt (pp. 83-86).