Wentworth, G. A. (George Albert), 1835-1906 · Boston, Ginn & company · leaf 193
the diagonal numbered 4 is .4 ; and 1 + .03 + .4 = 1.43. 20 SURVEYING. The Circular Protractor. This instrument (Fig. 14) usuallyconsists of a semi-circular piece of brass or german silver, hav-ing its arc divided into degrees and its centre marked. To lay off an angle with the protractor, place… … Fig. 14. Some protractors have an arm which carries a vernier, bywhich angles may be constructed to single minutes. To draw through a given point a line parallel to a givenline, make one of the sides of a triangle coincide with thegiven line, and, placing a ruler against one of the other sides,move…
Trigonometry · Surveying · Navigation
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
