MAGNETIC AZIMUTH. An arc of the horizon intercepted between the azimuth circle of a celestial object and the magnetic meridian.
MAGNETIC COMPENSATOR. An iron plate fixed near the compass, to neutralize the effect of local attraction upon the needle.
MAGNETIC NEEDLE. Applied to theodolites, ships' compasses, &c. A balanced needle, highly magnetized, which points to the magnetic pole, when not influenced by the local attraction of neighbouring iron. The magnetism may be discharged by blows, or a fall; hence, after an action at sea, the needles are often found to be useless, until re-magnetized.
MAGNETIC STORM. An extraordinary magnetic action indicated by delicate magnetometers in a magnetic observatory, not perceptible on ordinary magnets.
MAGNETIC TELEGRAPH. An instrument for communicating messages by means of magnetism.
MAGNITUDE OF AN ECLIPSE. The proportion which the eclipsed part of the surface of the sun or moon bears to the diameter; it is sometimes expressed in digits, but more frequently as a decimal, the diameter being taken as unity.
MAGNITUDES OF STARS. The relative degrees of apparent size in which the fixed stars are arranged, and classed according to the intensity of their light. The first six classes, designated by Greek letters, include all those which are distinctly visible to the naked eye.
MAHONE, Mahonna, or Maon. A former Turkish flat-bottomed vessel of burden, mentioned among the ships of Soliman Pasha, in the siege of Diu.
MAID. A coast name of the skate.
MAIDEN. A fortress which has never been taken.