The propagation of discontinuities of an electromagnetic field is considered for the case of a conducting medium. Conditions relating the values of the discontinuities in the electric and magnetic fields are obtained, and equations governing the transport of the discontinuities through space are derived. Such discontinuity conditions and transport equations are obtained both for the fields and for the

th order partial time derivatives of the fields. Previous derivations have treated the case of a nonconducting medium and have used distribution theory. The present treatment does not use distribution theory.