In his studies of terrestrial‐magnetic and atmospheric‐electric phenomena, Bauer's interests were not confined to the pure science‐problems in these fields. He also gave a great deal of attention to the question as to how the instruments and methods used in terrestrial‐magnetic and terrestrial‐electric research could be best adapted to the needs of the prospector. The writer in particular has enjoyed his advice and cooperation in a number of problems which arose in the development and calibration of magnetic instruments. While Bauer was Director of the Department of Research in Terrestrial Magnetism of the Carnegie Institution of Washington, this Institution became actively interested in the measurement of ground‐resistivities as a means of attacking certain problems related to earth‐current phenomena.