A treatise on surveying, comprising the theory and the practice (1906)
Gillespie, William Mitchell, 1816-1868, Staley, Cady, 1840- · New York D. Appleton · leaf 391
e End being Inaccessible (Fig. 544).Let A B be the required line, and B the inaccessible point. At A set off a perpendicular, A C, by Art. 810; then set theindex at 45°, and walk backward from A in the line of C A pro-longed, looking by direct vision at C, until you arrive at some point,D, from… … seen to coincide when at some point, D. Then A D = ^ A B. Ifthe index be set at 71° 34, then the measured distance will be ^ A B,and so on. If the index be set at the complements of the above angles, the TO MEASURE A LINE, ONE END INACCESSIBLE, 381 distance measured will be, in the first case,…
Surveying
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