Wentworth, G. A. (George Albert), 1835-1906 · Boston, Ginn & company · leaf 216
these parts of thecompass. a is the latitude arc. b is the declination arc. h is an arm, on each end of which is a solar lens having itsfocus on a silvered plate on the other end. c is the hour arc. n is the needle-box, which has an arc of about 36°. To run a north and south line with the solar… … BURTS SOLAR COMPASS. LAYING OUT PUBLIC LANDS. 45 level, and turn the sights in a north and south direction, ap-proximately, by the needle. Turn the solar lens toward thesun, and bring the su-ns image between the equatorial lines onthe silvered plate. Allowance being made for refraction, thesights…
Trigonometry · Surveying · Navigation
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