Magnetic Field of Force

The field of force established by a magnet pole. The attractions and repulsions exercised by such a field follow the course of the electro- magnetic lines of force. (See also Field of Force.) Thus the tendency of a polarized needle attracted or repelled is to follow, always keeping tangential to curved lines, the direction of the lines of force, however sweeping they may be. The direction of magnetic lines of force is a umed to be the direction in which a positive pole is repelled or a negative one attracted; in other words, from the north pole of a magnet to its south pole in the outer circuit. The direction of lines of force at any point, and the intensity or strength of the field at that point, expre the conditions there. The intensity may bc expre ed in terms of that which a unit pole at unit distance would produce. This intensity as unitary it has been proposed to term a Gau . (See Weber.) The direction of the lines of force in a magnetic field are shown by the time-honored experiment of sprinkling filings of iron upon a sheet of paper held over a magnet pole or poles. They arrange themselves, if the paper is tapped, in more or le curved lines tending to reach from one different conditions. Two near poles of like name produce lines of force which repel each other. (See Magnetic Curves.) A magnetic and an electro-magnetic field are identical in all e ential respects; the magnetic field may be regarded as a special form of the electro-magnetic field, but only special as regards its production and its defined north and south polar regions. Synonyms--Magnetic Spin (not much used).