Merchant Shipping Acts. Acts of Parliament governing the building? manning, employment, fitting-out, seaworthiness, registration? management, governance, etc., of British ships. Embrace numerous Acts, from 1882 onwards, the principal being those of 1894, 1906, and 1932.
Mercurial Barometer. Barometer that indicates atmospheric pressure by height of a balancing column of mercury—as distinguished from an aneroid barometer.
Mercury. White metal with melting point of –38.5C. Specific gravity about 13-55. Used in thermometers and barometers for registration purposes, and in some gyro compasses as a ballistic pendulum.
Mercury. Innermost of the planets. Greatest angular distance from Sun is about 29°. Very rarely observable, and then only near sunrise or sunset. Nautical almanac then gives a warning that its appearance may cause it to be mistaken for a star or another planet.