circumferentor การใช้

• Additional considerations include the number of times the circumferentor must be set up and aligned.
• However, the circumferentor remained in common use in mines and in wooded or uncleared areas, such as in America.
• A circumferentor consists of a circular brass box containing a magnetic needle, which moves freely over a brass circle, or compass divided into 360 sights is located on the North-South axis of the compass.