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
6 as drawn by Captain Duperrey. Itwill be noticed that they all pass through two points—one in the Northern Hemisphere,the North Magnetic Pole, and the other in the Southern Hemisphere, the South Mag-netic Pole. The lines cutting across the magnetic meridians at right angles, which inthe present… … Pole Au&tral Fig. 23.—Magnetic meridians for 1836 (Duperrey).
Magnetism, Terrestrial
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
