UPDATED 04/08/2009

Typical odometer cart, circa 1872.  The instrument is visible just above the hub of the wheel.

Surveying is the art of measuring and locating lines, angles and elevations on the earth's surface.  The principles are few; the applications are many and varied.  In the 19th century, surveying instruments varied widely by function, and required the exercise of great care, skill, attention to details and good judgment to obtain an accurate survey.

Below are some of the more commonly used scientific instruments that engineers used in gathering the data to complete their maps. 

• TRANSIT - for accurate measurements of bearing or elevation.

• WYE LEVEL - used is establishing profiles & contours of the land.

• SURVEYORS COMPASS - mounted on a tripod or Jacob's staff & used for quick measurements of a bearing or elevation.

• PRISMATIC COMPASS - a hand-held instrument that enables the user to read the bearing on the compass dial through a right angle prism while simultaneously viewing the object being sighted.

• SEXTANT - for measuring the vertical angle between the horizon and celestial objects.   Necessary for calculating latitude and longitude.

• ARTIFICIAL HORIZON - device to enable observation of the altitude of objects when the true horizon is not visible.

• REFLECTING CIRCLE - for sighting three objects (e.g. celestial) and measuring two angular separations simultaneously.

• ODOMETER - attached to the wheel of a cart of wagon for easy measurements of long distances.

• ANEROID BAROMETER - for measuring significant differences in elevation.

• CHRONOMETER - an extremely accurate timepiece required for accurate measurements with a sextant.

• GUNTERS CHAIN - 66' chain used for measuring short distances.

• LEVELING RODS - Used in combination with the sighting instrument to obtain topographical measurements.

• CHAINING PINS - for marking the point where the chain ends when measuring distances which exceed the length of the chain.

• DRAWING INSTRUMENTS - Used by cartographers to convert survey notes & sketches into a finished map.