- Dip circles (also dip needles) are used to measure the angle between the horizon and the Earth’s magnetic field (the dip angle).
- Our device consists of an accurately balanced magnetic needle with a strong magnetic field, made of cobalt steel, with hardened steel pivots working in agate cup bearings.
- The magnetic needle is pivoted at the centre of a circular scale, divided in four quadrants and graduated, 0-90-0-90° × 1°; for reading the inclination of the needle.
- The needle can be easily removed and accurately replaced for reversal, without the risk of damage to the pivot or bearing.
- The needle and the scale are housed in a non-magnetic aluminum casing with a glass window, both of which are capable of rotating about a vertical axis on a cast metal base.
- The vertical rotation can be read directly from a circular scale fitted on the base.
- The horizontal scale is graduated clockwise, 0-360 × 10, with a circular spirit level screwed to the face.
- The base is a heavy brass tripod with three adjustable leveling screws.
- 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 Earth’s magnetic field.