What is Dip Circle? Explain its working.

Dip circle,also called Dip Needle, or Inclinometer, instrument for measuring the inclination, or dip, of the Earths magnetic field. It consists essentially of a magnetic needle pivoted at the centre of a graduated circle. The assembly is mounted such that the needle swings vertically rather than horizontally, as does a compass needle. When the instrument is placed with the plane of the circle in the magnetic meridian of the Earth, the needle points in the direction of the Earths magnetic field.

(1) At equator the magnetic lines of force of earth are parallel to the horizon, therefore the needle will not dip there.

(2) At poles, the magnetic lines of force are almost vertical, the needle will show maximum dip(at north pole).