Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity (1854)
Davis, Daniel · Boston : Palmer and Hall · leaf 151
magnetic meridian, will point both to the magnetic pole 5, and to the north pole, N, both being in the same line. But, if the needle be placed at A, or any where except on the magnetic meridian, it will point to the magnetic pole alone, the two poles not being in the same direction. The several… … TERRESTRIAL MAGNETISM. 135 earth really having four magnetic poles, two strongand two weak: the strongest north pole is in Ameri-ca, the weakest in Asia. The line of no variationon the earths surface differs considerably from themagnetic meridian, and the lines of equal variationand equal dip are…
