ADRIENNE HART-DAVIS / SCIENCE PHOTO LIBRARY ADRIENNE HART-DAVIS / SCIENCE PHOTO LIBRARY
A magnetic compass resting on an Ordnance Survey map. The magnetic compass, an instrument for finding direction, consists of a thin piece of magnetic material with the north-seeking pole indicated, free to rotate on a pivot and mounted on a compass card on which the points of the compass are marked. The needle becomes aligned to the local component of the Earth's magnetic field, resting north to south. True north can then be found from tables of magnetic corrections.
Model release not required. Property release not required.