Principal facts of the earth's magnetism and methods of determining the true meridian and the magnetic declination. Reprinted from the United States magnetic declination tables and isogonic charts for 1902 (1909)
U.S. Coast and Geodetic Survey · Washington Govt. Print. Off · leaf 81
Pole Au&tral Fig. 23.—Magnetic meridians for 1836 (Duperrey). … Fig. 24.—Lines of equal magnetic declination in the polar regions for iSS; (Neumayer).
Magnetism, Terrestrial
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
