MAGNESIUM n.
dry air but tarnishing in moist air. It burns, forming (the oxide) magnesia, with the production of a blinding light (the so-called magnesium light) which is used in signaling, in pyrotechny, or in photography where a strong actinic illuminant is required. Its compounds occur abundantly, as in dolomite, talc, meerscha…
MAGNETIC; MAGNETICAL a.
m, so called; as, a magnetic sleep. See Magnetism. Magnetic amplitude, attraction, dip, induction, etc. See under Amplitude, Attraction, etc. -- Magnetic battery, a combination of bar or horseshoe magnets with the like poles adjacent, so as to act together with great power. -- Magnetic compensator, a contrivance conn…
MAGNETO-ELECTRIC; MAGNETO-ELECTRICAL a.
ing to, or characterized by, electricity by the action of magnets; as, magneto-electric induction. Magneto-electric machine, a form of dynamo-electric machine in which the field is maintained by permanent steel magnets instead of electro-magnets.
MANGANESE n.
An element obtained by reduction of its oxide, as a hard, grayish white metal, fusible with difficulty, but easily oxidized. Its ores occur abundantly in nature as the minerals pyrolusite, manganite, etc. Symbol Mn. Atomic weight 54.8.
MERCURY n.
A metallic element mostly obtained by reduction from cinnabar, one of its ores. It is a heavy, opaque, glistening liquid (commonly called quicksilver), and is used in barometers, thermometers, ect. Specific gravity 13.6. Symbol Hg (Hydrargyrum). Atomic weight 199.8. Mercury has a molecule which consists of only one ato…
METAMORPHOSIS n.
f a tadpole into a frog, or of a bud into a blossom. Especially, that form of sexual reproduction in which an embryo undergoes a series of marked changes of external form, as the chrysalis stage, pupa stage, etc., in insects. In these intermediate stages sexual reproduction is usually impossible, but they ultimately pa…
MILLING n.
alternately with sifting and sorting the product. -- Low milling, milling in which the reduction is effected in a single crushing or grinding. -- Milling cutter, a fluted, sharp-edged rotary cutter for dressing surfaces, as of metal, of various shapes. -- Milling machine, a machine tool for dressing surfaces by rota…