A possible m ode of p ro p ag atio n of the ' slow ' or tail com ponent in atm ospherics In this paper a possible surface wave mode of propagation for the slow or tail component in an atmospheric is discussed. Surface wave solutions for the propagation of electromagnetic waves between infinite plane conductors are set up and it is shown that if one of the layers is of finite conductivity there is a solution which corresponds qualitatively with the observed velocities and periods of the slow component.