A Treatise on the Principal Mathematical Instruments Employed in Surveying ...

accuracy add the log adjustment air-bubble altitude angular artificial horizon attached axis azimuth circle barometer bisected bubble centre chain circumpolar star clamp co-latitude co-secant coincide compass computed correct cross-wires declination determined deviation difference of level ditto divided divisions employed equal exactly eye-end feet foot-screws glass Gunter's chain half height horizon-glass horizontal wire inches index error index-glass instru interval latitude length line of collimation longitude lower manner mean measured ment meridian meridian altitude method micrometer microscope middle minus minutes moon moon's motion moved Nautical Almanac needle observed obtained paper parallax parallel plate-screws perpendicular plane polar distance portable position prime vertical protractor purpose quantity reading represents right angles right ascension round scale screw sextant side sidereal sine spirit-level staff subtract sun's survey Table taken tangent tangent-screw theodolite transit instrument TROUGHTON's tube turning vane vernier vertical circle zenith distance zero