=marine=—A man in the naval service serving something like a soldier on board a warship. Nowadays the duties of marines often take them ashore where their services are identical with those of soldiers. =mariner=—Anciently a first-class or able-bodied seaman. =martingale=—The rope extending downward from the jib-boom to the “dolphin striker.” Its duties are those of a stay, or brace. =mast=—A long piece or system of pieces of timber or metal placed nearly perpendicularly to the keel of a vessel to support rigging, wireless antennæ, halyards, etc. =master=—The captain of a merchant vessel. =mate=—literally the master’s assistant. There may be as many as four or five mates on a ship, rated first, second, third, etc. They are officers next in rank to the master. =mess=—At sea a company of men or officers who eat or live together. =’midships=—The same as AMIDSHIPS. =mile=—A nautical mile equals one sixtieth of a degree of latitude, and varies from 6,046 feet at the equator to 6,092 in latitude 60 degrees. =mizzen=—Generally the third mast from the bow of a ship carrying three or more masts is called the mizzenmast. The sails set from this mast have the word “mizzen” prefixed to their names, as _mizzen_ topsail, _mizzen_ topgallant sail, etc. Also parts of the mast prefix the word, as _mizzen_ topmast. =moonraker= (or =moonsail=)—In square-rigged ships the sail set above the skysail. (Very rare.) =moor=—To moor is to make a ship fast to a mooring which is a kind of permanent anchor to which a buoy is attached. =Mother Carey’s chicken=—A small seabird, properly called the stormy petrel (_Procellaria pelagica_). =nautical mile=—See MILE. =naval architecture=—The science of designing vessels. =navigation=—The science which enables seamen to determine their positions at sea and to lay down courses to be followed. =nun buoy=—A buoy which shows above water in the shape of a cone. =oakum=—A substance to which old ropes are reduced when picked to pieces. It is used in calking the seams of boats and in stopping leaks. =oar=—An instrument used in propelling boats by hand. It may be of any length over four or five feet, although, as it is meant to be operated by man power, it must be limited in size so as not to constitute too great a weight. It is made up of a handle, a shaft, and a flat section meant to come in contact with the water. At about one third of the distance from the handle to the end of the blade it rests in a special fitting called an oarlock or a rowlock. By submerging the blade in the water and pulling the handle in a direction at right angles to the length of the oar it tends to propel the boat. It differs from a paddle in that a paddle does not rest in a lock. A sweep is a very large oar, generally operated by several men. =oilskins=—Waterproof coats and trousers worn over other clothing at sea.