An automatic level is a surveying instrument used to measure horizontal and vertical angles with high precision. It consists of a telescope mounted on a leveling base that automatically adjusts itself to a horizontal position. This feature allows surveyors to take accurate measurements without needing to manually level the instrument. To use an automatic level, a surveyor sets it up on a tripod over a known point and looks through the telescope to align with a target, often called a staff. The instrument's internal compensator ensures that the line of sight remains level, making it easier to determine elevations and distances in construction and land surveying projects.