General Info: Survey LEVELS and TRANSITS were work horses in their day on the Construction site but have been replaced by easier and more accurate instruments. An Survey LEVEL is merely a telescope that rotates 360° to determine a level plane, as well as allowing the reading of horizontal angles.
Using leveling screws, tubular vials are used to indicate when the instrument is level. TRANSITS are usually leveled using tubular vials, also, often both on the plate and on the telescope itself. TRANSITS are more accurate in determining horizontal angle, usually by the use of a vernier scale. The telescope on a TRANSIT can be pivoted in the vertical 360° as well as turned horizontally 360°.
The time needed to set up Survey LEVELS and TRANSITS and their limitation of angular accuracy account for their diminished use. However, an instrument that can be pivoted in the vertical is still required for determining LINE when setting up a pipe laser.