Also, the needle starts to point up or down when getting closer to the poles, because of the so-called magnetic inclination.

Magnetic inclination and local variations were known before Robert Norman, but his pamphlet had a greater influence than the earlier work.

Although some of the rocks needed a more complex and thorough analysis, most samples yielded data suitable to make a preliminary determination of magnetic inclinations.

In geology, the magnetic inclination is the angle made by a compass needle with respect to the horizontal surface of the Earth at a given latitude.

Robert Norman was a 16th-century-English mariner, compass builder, and hydrographer who discovered magnetic inclination, the deviation of the Earth's magnetic field from the vertical.

Magnetic dip, dip angle, or magnetic inclination is the angle made with the horizontal by the compass needle of a vertically held compass.

In the late 1590s Henry Briggs, a professor of geometry at Gresham College in London, had published a table of magnetic inclination with latitude for the earth.

Magnetism is a vector and so magnetic field variation is made up of palaeodirectional measurements of magnetic declination and magnetic inclination and palaeointensity measurements.

The greatest currents and voltages were obtained when the difference in depth was such that a line joining the two electrodes was in the direction of the magnetic dip, or magnetic inclination.

He experimented with such physical models in an attempt to explain problems in navigation due varying properties of the magnetic compass with respect to their location on the earth, such as magnetic declination and magnetic inclination.

Passing a small compass over the terrella, Gilbert demonstrated that a horizontal compass would point towards the magnetic pole, while a dip needle, balanced on a horizontal axis perpendicular to the magnetic one, indicated the proper "magnetic inclination" between the magnetic force and the horizontal direction.

Such magnetic inclination was described as early as the 11th century by Shen Kuo in his Meng Xi Bi Tan and further investigated in 1581 by retired mariner and compass maker Robert Norman, as described in his pamphlet, The Newe Attractive.