Remarks on the comments and reply on "The electromagnetic field of a vertical electric dipole over the Earth or sea"

The author discusses the comments by Yokoyama (see ibid., vol.43, no.5, p.541, 1995) and the reply by King and Sandler (see ibid vol.43, no.5, p.542, 1995) on the definition of the numerical distance and related matters in the Sommerfeld problem of a vertical electric dipole over a dissipative half-space. It appears that the two definitions are equivalent in the sense that the effective field quantities are essentially the same. But a more important point is that possible confusion has been generated on the relationship between K.A. Norton's [1937] original papers and the more recent writings on the subject.