Abstract
-The author measured the magnetic susceptibility of the Japanese crude mineral oil and from the relation ship between volume magnetic susceptibility and mag-netic correlation index (MI) he classified the crude into four. Investigating the relati-onships between magnetic susceptbility and specific gravity, viscosity, residual carbon, freezing point, flash point, distillation test, etc. he further itemized them of which he described the characteristics, distributions of the crude in the point of oil layer, oil field, district and stratum respectively.
