Graphical scales for mapping potential functions

Abstract Graphical scales can be prepared and used for rapid determinations of potential field values which depend only on the distances between two fixed points. The method can be applied to determine the potential at the surface of a homogeneous earth due to a current pole at its surface, and to the potential at the surface of the earth considered as an infinite insulator separated from the surface by a parallel plate of finite resistivity. Portions of two typical scales and two sets of equipotential curves drawn by use of the scales are shown.