Encyclopedia of Geomagnetism and Paleomagnetism

2007 Edition
| Editors: David Gubbins, Emilio Herrero-Bervera

Main Field Maps

  • Mioara Mandea
Reference work entry
DOI: https://doi.org/10.1007/978-1-4020-4423-6_209

Historically, in navigating long distances, the compass was as important an instrument for indicating direction as the sandglass was for marking time. However, until the 17th century, everyone believed that magnetic north coincided with true north, and mariners were unaware of this variation (see  Geomagnetism, history of); consequently, as they sailed west they found their position did not correspond with their location according to charts. Having learned that true north differed from magnetic north, instrument makers in some of the northern countries produced compasses in which the compass card was mounted on the magnetic needle in alignment with the amount of magnetic variation. Thus, while the needle pointed to magnetic north, the fleur‐de‐lison the compass card indicated true north. By this arrangement the compass had a built‐in correction for the magnetic variation. This was fine, as long as voyages were limited to regions where the amount of variation did not appreciably...

This is a preview of subscription content, log in to check access.

Bibliography

  1. Barraclough, D.R., 2000. Four hundred years in geomagnetic field charting and modelling. In Schröder, W. (ed.), Geomagnetism. Research Past and Present. Bremen‐Roennebeck: IAGA, pp. 93–111.Google Scholar
  2. Clark, T.D.G., 2000. Edmond Halley's voyages in the Paramore and the first isogonic chart of the Earth's magnetic field. In Schröder, W. (ed.), Geomagnetism. Research Past and Present. Bremen‐Roennebeck: IAGA, pp. 61–71.Google Scholar
  3. Hansteen, C., 1824. Magnetiske Intensitets‐Iagttagelser, Anstillede paa forskjellige Reiser i den nordlige Deel af Europa. Magazin for Naturvidenskaberne, 4: 268–316.Google Scholar
  4. Hellmann, G., 1909. Magnetische Kartographie in historisch‐kritischer Darstellung. Abhandlungen des Königlichen Preussischen meteorologischen Instituts 3: 61.Google Scholar
  5. Howarth, R.J., 2003. Fitting geomagnetic fields before the invention of least squares: II. William Whiston's isoclinic maps of Southern England (1719 and 1721). Annals of Science, 60: 63–84.CrossRefGoogle Scholar
  6. Humboldt, A., von and Biot, J.‐B., 1804. Sur les variations du magnétisme terrestre à différentes latitudes. Lu par M.Biot à la clsse des sciences mathématiques et physiques de l'Institut National, le 26 frimaire an 13, pp. 24.Google Scholar
  7. Langel, R.A., 1987. Main field. In Jacobs, J.A. (ed.), Geomagnetism. London: Academic Press, pp. 249–512.Google Scholar
  8. Mandea, M., 2000. French magnetic observation and the theory at the time of DE MAGNETE. In Schröder, W. (ed.), Geomagnetism. Research Past and Present. Bremen‐Roennebeck: IAGA, pp. 73–80.Google Scholar
  9. Maus, S., Lühr, H., Balasis, G., Rother, M., and Mandea, M., 2004. Introducing POMME, the POtsdam magnetic model of the Earth in CHAMP. In Earth Observation with CHAMP, Results from Three Years in Orbit. Berlin‐Heidelberg: Springer, pp. 293–298.Google Scholar
  10. McLean, S., Macmillan, S., Maus, S., Lesur, V., Thomson, A., and Dater, D., 2004. The US/UK World Magnetic Model for 2005–2010, NOAA Technical Report NESDIS‐NGDC‐1.Google Scholar
  11. Mitchell, A.C., 1937. Chapters in the history of terrestrial magnetism. II. The discovery of the magnetic declination. Terrestrial Magnetism and Atmospheric Electricity, 42: 241–280.CrossRefGoogle Scholar
  12. Nautonnier, G., 1602–1604. Mecometrie de leymant, c'est a dire La maniere de mesvrer les longitudes par le moyen de l'eymant. Venes: ches l'autheur, 343 pp.Google Scholar
  13. Neubert, T., Mandea, M., Hulot, G., von Frese, R., Primdahl, F., Jorgenson, J.L., Friis‐Christensen, E., Stauning, P., Olsen, N., and Risbo, T., 2001. High‐precision geomagnetic field data from the Ørsted satellite. EOS, 82: 81–87.CrossRefGoogle Scholar
  14. Ultré‐Guérard P., and Mandea, M., 2000. Declination and longitude in France in the early 17th century. In Schröder, W. (ed.), Geomagnetism. Research Past and Present. Bremen‐Roennebeck: IAGA, pp. 81–92.Google Scholar
  15. Wright, E., 1610. Certaine errors in Navigation, detected and corrected, Printed by Feelix Kingstrõ. London, 354 pp.Google Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Mioara Mandea

There are no affiliations available