Leveling: Barometric, Trigonometric and Spirit

accuracy accurate adjustment aneroid angle approximate atmosphere atmospheric refraction backsight barome barometric formula boiling bubble cistern cloth coefficient of refraction computed correction deduced density determined difference of altitude difference of elevation difference of level diurnal edition eleva eliminate ence Engineering equilibrium eral Errors due feet formula geodesic leveling Gilbert gradient Guyot's Collection heat height horizontal hygrometer hypsometric illus Illustrated inch instru instrument ivory point justment l-log length of sight line of light lower station mean measured ment mercurial barometer meters method micrometer Mississippi River Commission moisture morocco numerous observations Ordnance Survey perature Plantamour's plates Practical pressure Prof scale screw self-reading source of error spirit level static equilibrium statical formulæ stratum strument surface T'+T tables tance target telescope temperature temperature and humidity term thermometer tical tion Treatise triangulation trigono tube ture U. S. C. S. Report U. S. Lake Survey variation Williamson wood-cuts