Circumferentor

A circumferentor, or surveyor's compass, is an instrument used in surveying to measure horizontal angles.

[2] Circumferentors were made throughout Europe, including in England, France, Italy, and Holland.

However, the circumferentor remained in common use in mines and in wooded or uncleared areas, such as in America.

Then, turn the instrument around, with the fleur-de-lis still towards you, and direct the sights to G; note the degree at which the south end of the needle point, such as 182°.

To take the plot of a field, forest, park, etc., with a circumferentor, consider region ABCDEFGHK in Figure 2, an area to be surveyed.

In the same manner, proceed to D, E, F, G, H, and lastly to K; still noting the degrees of every bearing, or angle, and the distances of every side.

Additional considerations include the number of times the circumferentor must be set up and aligned.