A Bion-Type Surveyor's Cross - Circa 1700

The Surveyor's Cross is one of the oldest, if not the oldest, surveying instrument in the world. The desire to build cities based on a grid pattern goes back thousands of years, and ancient civilizations (like the Egyptians and Greeks) developed ways to measure right angles to accomplish this goal. The Roman Groma is the most well-known ancient right angle measuring surveying device. The Surveyor's Crosses on this webpage are all evolved over time from the Roman Groma. And it is worth noting that instrument makers continued to produce right angle measuring devices well into the 20th century - like the American City Transit made by K&E.

Interestingly, George Adams, the famous English Instrument maker in the second half of the 18th Century, claimed that surveyors who surveyed using only a chain also likely used a Surveyor's Cross. I can see how using a Cross would greatly enhance the accuracy and efficiency of surveying with a chain. But Surveyor Chains seemed to have survived in FAR GREATER NUMBER than Surveyor Crosses, so that raises questions about just how many surveyors actually used Crosses while surveying with a chain.