Robert Norman is noted for The Newe Attractive, a pamphlet published in 1581 describing the lodestone (magnet) and practical aspects of navigation. More importantly, it included Norman's measurement of magnetic dip, the incline at an angle from the horizon by a compass needle discovered by Georg Hartmann in 1544. This effect is caused by the Earth's magnetic field not running parallel to the planet's surface. Norman demonstrated magnetic dip by creating a compass needle that pivoted on a horizontal axis. The needle tilted at a steep angle relative to the horizon line.