Declination is due to the fact that the geographical and magnetic poles do not coincide.
He is trying to get himself north and south, so as to bring the body into harmony with the magnetic poles of the earth.
Like magnetic poles repel one another; unlike magnetic poles attract one another.
The force exerted between two magnetic poles varies inversely as the square of the distance between them.
Its germ was the Cartesian vortices, suggested by the curvilinear forms of iron filings in the vicinity of magnetic poles.
From the sun's magnetic poles branch out the polar rays, nearly straight throughout their visible extent.
The nearer the magnetic poles the more nearly vertical does the freely suspended needle become.
On approaching the magnetic poles, compasses become sluggish, for the horizontal deflecting force falls off rapidly.
Finally it was whipping around steadily, the brushes on its shaft reversing the magnetic poles with each half circle of the arc.
The currents in the plate are therefore from the centre by the magnetic poles towards the circumference.