Christopher Hansteen (1784–1873): A pioneer in the study of terrestrial magnetism



The 200th anniversary of the birth of Christopher Hansteen (1784–1873) was celebrated in 1984. He contributed significantly to the knowledge of the earth's magnetic field, and his observations were essential for a realistic theory, based on spherical harmonic analysis, for mapping the field. A review of Hansteen's pioneer research in geomagnetism together, with some of his main ideas concerning the aurora, is given.