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 152
It is immediately obtained by comparingthe direction of the needle with the north star whenit crosses the meridian, or by calculation when thenorth star is at its greatest elongation. An obser-vation of the sun, however, is usually preferred. The r,. an Jatltudc of a placc, Fis^. 83. ^ M^ A (Fig.… … See Bowditchs Navigator. 136 D AVI S S M ANUAL. angle MAS will be the magnetic bearing of thesun west. Suppose this angle to be observed by thesurveyors compass, and found equal to 7Q^, the timebeing exactly noted. The angle N A S, the truebearing of the sun at the time, is then calculated.Suppose…
