A Treatise on Levelling, Topography, and Higher Surveying

adjustment angular back-sight barometer bisect the target bottom bring the bubble bubble-tube centre CHAPTER circle clamp column compass contour-lines coördinates correction cross-hairs curvature determined difference of heights direction Dumpy Level end for end equal error eye-piece feet field-book fore-sight formula gamboge given ground half-way back hold the rod horizon-glass horizontal inch latitude length level line line of collimation line of sight lower one end main socket mark means measured mercury method miles millimetres mirror moved object object-glass parallel perpendicular plane of reference plate-screws plumb-line precisely raising or lowering reading represented rod held scale screws set the instrument sextant shade shaft side slope spherical spherical excess stakes starting-point station surface Surveying taken temperature thalwegs theodolite tint transit triangle tripod tube turn the telescope turning-points upper usually vernier vertica vertical angles vertical plane zenith distance