NORMAN, ROBERT

(fl. England, late sixteenth century)

navigation, magnetism.

Little is known of Norman, an English instrument maker of the late sixteenth century, other than that lie was for a considerable time a sailor and later had a house at Radeliffe, where he sold navigational instruments. At a time when sailing and the construction of good compasses were of primary importance, Norman established his reputation not only as a maker of superior instruments but also as one interested in their irregularities.

In making magnetic compasses, Norman noticed that the needle did not remain parallel to the earth’s surface but that the north-seeking pole dipped toward the earth. He constructed his compasses with a wax counterbalance on the south-seeking pole to counteract this dip; when, by accident, he found that the attached wax did not serve as an equalizer if the needle was shortened, he became interested in the theory of the phenomenon.

In The Newe Attractive (1581), a treatise on the lodestone, Norman discussed the known properties of the magnet; suggested that the orientation of the compass was due to its turning toward, rather than its being attracted to, a certain point; and related his newly discovered deviation of the needle from the horizontal. He measured this deviation to be 71°50’ at London and was interested in finding its value at other points on the earth’s surface.

This work appears to have been well known and was one of the few writings on magnetism favorably referred to by William Gilbert. In De magnete (1600), Gilbert credited Norman with the discovery of the dip of the magnetic needle and suggested that this property could be used to measure latitude on the earth’s surface.

Norman also published The Safegardo of Saylers (1590), a book of sailing directions which he translated from Dutch.

BIBLIOGRAPHY

Norman’s writings are The Newe Attractive, Containying a Short Discourse of the Magnes or Lodestone, and Amongst Other His Vertues, of a Newe Discovered Secret and Subtill Properties, Concerning the Declinying of the Needle Touched Therewith Under the Plaine of the Horizon (London, 1581); and The Safegarde of Saylers (London, 1590).

Suzanne Kelly