Elements of military sketching and map reading (1917)
Barnes, John Bryson, 1876- · New York : D. Van Nostrand · leaf 26
ear to move forward or back of O. This apparentcourse of the pendulum (Fig. 6) is a sector that canbe divided into degrees. In the diagrams, from C toline A—B is assumed to be 5.7 inches, and the divi-sions on A—B are i-io of an inch apart. Each divi- SOME SKETCHING INSTRUMENTS 17 sion on a slope… … Fig. 6. by the pendulum (Figs. 7 and 8). Forward is a minusand backward is a plus elevation. It is usually moreconvenient to use both hands in sighting and to holdthe plumb-line in place against the board with the leftthumb when it is turned to be read. The slope boardis constructed on the under…
Military topography · Maps, Military
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