Another remarkable and evident manifestation of the influence of the
magnetism of the earth upon the needle is the inclination or dip of the
latter which is a deviation from its horizontal place in a downward
direction in northern regions of its north, and in southern regions of
its south pole. In balancing the needle on the card, on account of this
dipping, a small weight or movable piece of brass is placed on one end
of the needle, by the shifting of which either nearer to or further
from the center, the needle will always be balanced.