Magnesium

one of the metallic elements. In chemical behavior it resembles calcium. Its compound with oxygen was long mistaken for lime. Davy separated magnesium in 1808 by electrolysis. It has the color of silver. It has a specific density of 1.75, being considered lighter than aluminium. It melts at about the same temperature as zinc and tarnishes in air a little more readily than that metal. It may be hammered into thin sheets and drawn into wire, but it has little strength. Pure magnesium is sold for use in chemical laboratories in the form of a ribbon. It may be kindled in a candle flame like a pine shaving, and will continue to burn, giving out an intense light. A wire .012 of an inch in diameter will give a light equivalent to that of seventy-four standard candles.

Magnesium enters into the composition of certain medical remedies. One of its compounds is well known as Epsom salts. The metal enters largely into the composition of many rocks and minerals, notably magnesian-limestone, meerschaum, talc, serpentine, and hornblende. Despite the inflammable nature of magnesium, it is one of the elements entering into the composition of asbestos, a well known fireproof substitute for cloth, paper, and pasteboard. The oxide, known usually as magnesia, is a white powder without taste or odor. Mixed with water into a paste it sets like plaster of paris. Magnesia is hardly soluble in water but it absorbs moisture slowly. Its great merit in the arts is a high degree of infusibility. Heated in the flame of the blowpipe it gives out a white light much like a limelight. Mixed with clay it is used in the manufacture of crucibles and firebrick. The name of the element is derived from magnesia, found originally, it is reputed, in the province of Magnesia, Thessaly. Magnesium chloride is added to sizing of cotton cloth to prevent mildew.

Magnesium is one of the elements essential to plant life. Unless a seed has a proper amount of magnesium in its makeup it will not sprout. In a form called magnesite, a compound with carbon, magnesium is used in large quantities to "digest" or loosen the fiber of wood pulp. The commercial article is produced chiefly in Greece and Austria. California contributes a few thousand tons yearly.