A treatise on surveying, comprising the theory and the practice ; (1887)
Gillespie, W. M. (William Mitchell), 1816-1868, Staley, Cady, 1840- [from old catalog] ed · New York, D. Appleton and company · leaf 367
uts at eachend (one above, one below the bar), which may be moved with anadjusting-pin. The use of these nuts will be explained under Ad-justments. Attached to the center of the level-bar is a steel 352 LEVELING. spindle, made so as to turn smoothly and firmly in a hollow cylin-der of bell-mefcal ;… … and are held apart by the four plate-screws, QQQQ. which passthrough the upper one, and press against the lower one. AIR-BUBBLE OR SPIRIT LEVELS. 353 To level the instrument, turn the telescope till it is broughtover a pair of opposite parallel plate-screws. Then turn the pairof screws, to which…
Surveying
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