What Does Circumferentor Mean?

A circumferentor, or surveyor's compass, is an instrument used in surveying to measure horizontal angles. It was superseded by the theodolite in the early 19th century.

How do you use a Circumferentor?

To measure an angle with a circumferentor, such as angle EKG (Figure 1), place the instrument at K, with the fleur-de-lis in the card towards you. Then direct the sights, until through them you see E; and note the degree pointed at by the south end of the needle, such as 296°.

How does a surveyor's compass work?

The surveyor's compass (Fig. 11) is an instrument for determining the horizontal direction of a line with reference to the direction of a magnetic needle. The needle is balanced at its center on a “pivot” so that it swings freely in a horizontal plane.