Adam Fenstermaker, age 17, of Gadsden, Ala., for his question:

WHAT IS A THEODOLITE?

A theodolite gives more precise readings than a transit gives. Some theodolites permit measurements to closer than one second of arc, which is one thirty six hundredth of a degree.

Most theodolites are mounted on tripods or three legged stands.

A theodolite has a telescope that permits accurate sighting in any direction. A horizontal plate below the telescope provides readings around the horizon in degrees, and in divisions of degrees called minutes and seconds.

A vertical plate and scale, mounted to the left of the telescope, permit vertical readings to be taken.

A well leveled theodolite can even be used as an astronomical transit for finding the latitude of a place. This is done by focusing the telescope on the sun or some other star, reading the theodolite and making mathematical calculations.