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Simultaneous observations of electric and magnetic fields were made at Tottori Sand Dune and about 100 events were studied in some detail. Strong polarization and large daily variation were found in the electric field. Apparent resistivity was estimated from the ratio of the electric field to the magnetic field and a transfer function was calculated by taking the magnetotelluric method into account. Characteristic features of the field were found in these treatments especially for short period variations.

A new method of analysis of the daily geomagnetic variations is proposed and discussed. This method is a combination of the two (analytical and numerical) methods already introduced and developed. Although the method is not perfect with some ambiguity involved, it may be useful for the purpose of practical analysis.

A consideration is made for the practical application of Weaver's formulae and for recording separately the external and internal parts of short-period geomagnetic variations in a region of local anomaly, and the possibility for detecting the magnetic effect which might be expected from a time-change in the underground electrical state is discussed. It is shown that the effect would be very small, but it might be possible to find out the effeect on the record if we employ magnetometers of very high sensitivity and the location of anomaly is not so deep.

An observation of geomagnetic and telluric pulsations was made at Tottori Sand Dune. Hodographs for pulsations, mainly Pc 4, were studied and it was found that the rotations of the vectors were clockwise at night and that the main axis of hodograph changed its direction with local time.