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 149
ficientlyhorizontal for use in any part of the northern tem-perate zone, except for delicate experiments. Com-pass needles intended to be employed on voyages ortravels, where great variations in latitude may be ex-pected, are provided with a small weight sliding uponthe magnet. By a proper… … TERRESTRIAL MAGNETISM. 133 211. In Fig. 81, the North American magneticpole is represented near S, the north geographical poleof the earth. The line L Y is nearly the present lineof no variation (see <§> 215), and the curved line nearthe geographical equator is the magnetic equator,where the…
