dipping needle

A magnetized needle, moving in a vertical plane, on an axis which pa es at right angles exactly through the center of gravity. When thus mounted it will, if placed anywhere not in the magnetic equator, dip or point downward. The position of the magnetic pole can thus be de termined from the intersection of two or more lines formed by making experiments with the dipping needle at various places. The inclination or dip of the magnetized needle was not known to the Chinese, who had discovered its variation during the twelfth century. This element of terrestrial magnetism appears to have been discovered by Robert Norman, compa -maker of Ratcliff, London, who detected the dip, and published the fact in 1576. He contrived the dipping-needle, and found the dip at London to be 71° 50'. [DIP-CIRCLE.] Captain Sir James Ro , the celebrated Arctic navigator, reached the magnetic pole, latitude 70° 5' 17" N., and longitude 96° 46 45" W., on the first of June, 1831. The amount of dip was 89° 59′.