1086.    FREUND, M.  Properties of Natural and Synthetic Paraffinic Lubricating Oils.  Petroleum (London), vol. 33, No. 48, 1937, pp. 1-5; British Chem. Abs., 1938, B, p. 131.

        Three groups of products of high-pressure hydrogenation, solvent extraction, chemical synthesis (Fischer process), and conventional acid-earth refining were examined regarding properties dependent on mean molecular weight and H content.  Each group consisted of oils of identical refractive index at 50°.  The generalization connecting d with these properties holds satisfactorily, except for synthetic oils, which behave somewhat differently from other types.