Theoretically scalar potential Φ waves with a longitudinal electric field E⃗ in the direction of propagation must exist. A centrally fed ball antenna, 6 cm diameter, producing a pulsating 433.59 MHz spherical source charge, generated such a wave, that was detected by an identical ball antenna. The longitudinality of E⃗ was demonstrated by intervening a cubic array of 9 half-wavelength wires, that absorbed the wave when the wires were parallel (but not when perpendicular) to the direction of propagation. The signal from the ball antenna source, placed 4.0 m above ground and receiver 4.4 m above ground, was measured as a function of distance, yielding satisfactory agreement with theory, including 2 expected interference minima produced by an image source induced in the Earth. Only waves can yield such an interference and can be reflected from the Earth's surface and vary as the inverse square of distance.

It is assumed that the flow of seismic energy from an underground nuclear explosion or earthquake in the near range (i.e., distances of less than 1000 km) may be estimated by the diffusion equation in cylindrical geometry with a diffusivity varying directly as frequency. A term is included to allow for the dissipation of energy due to the anelasticity of the earth. The mean period and amplitude of a seismogram are thereby derived as functions of the time of arrival and range. The peak particle velocity is derived as a function of range. A preliminary comparison with observations of the seismic waves produced by an underground nuclear explosion indicates satisfactory over‐all agreement.

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A dyke of sulfide ore may be geophysically prospected by observing its electromagnetic response to a slowly oscillating magnetic dipole source. An excellent first approximation of the fields generated is obtained by considering the idealized case of a dyke of infinite conductivity and vanishing thickness in a vacuum. Surprisingly, this idealized problem can be solved exactly in terms of a newly discovered Green’s function for Laplace’s equation (in three dimensions) which is simply expressed in closed form. The magnetic scalar potential and the magnetic field are given for final results.

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