Lead

A grey malleable metal, very soft, marks paper; can only be brought to a dull polish. Should be cleaned by scraping or caustic soda; darkens slightly on exposure to the atmosphere, but after this it is permanent and no further change takes place. Is annealed by raising to the temperature of boiling water. May be soft soldered; is often joined by what is known as autogenous soldering or burning, especially for vessels used in chemical work. Wire and pipes can be made of lead by extrusion, squirting, or pressure.

Magnesium

A silvery white metal. Burns with a very bright flame when heated. Used largely in pyrotechny and photography in the form of powder or ribbon; in the latter form it will light by the aid of a match. It is readily soluble in dilute hydrochloric acid and in dilute sulphuric acid.

Manganese

A grey metal with a reddish tinge, very brittle. Used mostly for alloying with iron, copper, and nickel in the manufacture of very hard steel and mild steel; has the effect of toughening and generally improves the quality. Manganese is not usually used pure but in the form known as ferro-manganese. Manganese Bronze.-A light brown alloy which takes a high polish and is malleable; sometimes called white bronze. Is cleaned by immersion in dipping acid; is not corroded by the action of sea-water. May be soft soldered, silver soldered, and brazed. Used largely for screw propellers and marine engineering owing to its great transverse strength, toughness, hardness, and the facility with which it can be cast sound. It is equal in strength to mild steel, and can be worked either hot or cold, but should be forged at a cherry-red heat.

Manganese Steel

A greyish white metal; takes a good polish. Very strong and tough; toughness is improved by quenching in water from a white heat. Cannot be hardened like tool steel or welded; all shaping should be done while hot. Makes sound castings but contracts considerably.

Mercury Or Quicksilver

A silvery white metal, liquid at ordinary temperatures. Used in making amalgams and in scientific instruments.

Mild Steel

A greyish-white metal, very malleable hot or cold, easily welded and forged into shape while hot; takes a good polish. Cannot be hardened or tempered like tool steel. Stronger than wrought iron, which it is gradually superseding for constructional purposes. Can be soft soldered, silver soldered, brazed, and welded either by the blacksmith's method or by the oxy-acetylene method; the former is the stronger.

Muntz Metal

So called after the patentee, Sir G. F. Muntzof Birmingham. Really it is a malleable brass; takes a high polish. May be cleaned by immersion in dipping acid, and can be annealed and soldered like brass. It is sometimes called yellow metal sheathing, as it was used largely for covering the bottoms of wooden ships; it is now used for condenser tubes and marine work, as it is not affected by sea-water to any great extent. Can be forged at a red heat. Nickel Steel.-A special steel of a white colour; has a fibrous structure; takes a high polish. Very strong, tough, has great power of resisting shocks, and has a higher elastic limit than carbon steel, and is not corroded so quickly by sea water. Can be welded if the proportion of nickel is not more than three per cent. Used largely for armour plates and crank shafts.