The theory and practice of surveying. Designed for the use of surveyors and engineers generally, but especially for the use of students in engineering (1886)
Johnson, J. B. (John Butler), 1850-1902 · New York, J. Wiley & sons · leaf 550
n the target. This target may be set onany convenient azimuth from the observation-station, as uponone triangulation station when the observations are taken atanother, thus obtaining directly the azimuth of this line. 381. Illumination of Cross-wires.—Various methods areused to illuminate the… … A very good reflector may be made from a piece of newtin, cut and bent as in Fig. 144. The straightstrip is bent about the object end of the tele-scope tube, leaving the annular elliptic pieceprojecting over in front. This is then bent toany desired angle, preferably about forty-fivedegrees, and…
Surveying
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