Abstract: A terrestrial magnetism responsive device adapted to be worked using a north or south seeking magnet in both north and south headings, the device including a housing having a north or south seeking magnet therein. The magnet is suspended adjacent one pole by a sensitive spring to permit the magnet to be movable horizontally, when released, from a north pointing position or a south pointing position. Secured and balanced on the seeking or free end of the magnet is a soft iron rod, generally at ninety degrees to the magnet and having substantially the same diameter as the magnet. The rod is balanced along with the magnet so that the magnet and rod together will move horizontally. The housing is rotatable on a plate by which it is held and during operation is fixed on the plate to be moved horizontally in the direction of an area to be explored.

Abstract: A terrestrial magnetism responsive device adapted to use a north or south seeking magnet in both north and south headings, the device including a housing having a north or south seeking magnet therein, the magnet being suspended adjacent one pole by a sensitive spring to permit the magnet to be movable horizontally, when released, from a north pointing position or a south pointing position. The method includes the releasing of a north or south seeking magnet in the housing so that it is free to move easterly or westerly on the spring, moving the housing over the areas to be explored, and recording the east/west diversions of the magnet and the exact locations of the diversions.

Abstract: A terrestrial magnetic responsive device having a float carrying magnetic north-seeking means and responsive not only to magnetic north, but also to local magnetic force fields, said device having a liquid evaporation and liquid movement control means.