Abstract
A result of Debye, Anderson, and Brumberger [P. Debye, H. R. Anderson, Jr., and H. Brumberger, J. Appl. Phys. 2 8, 679 (1957)] for isotropic porous media states that the derivative of the two‐point spatial correlation at the origin is equal to minus one‐quarter of the specific surface area. This result is generalized for nonisotropic media by noting that the angular average of the anisotropic two‐point spatial correlation function has the same relationship to the specific surface area.