[Gk. arsen, a male (on account of its strength).] A metallic element, seldom found free in nature, but frequently found in combination with Other elements, such as sulphur, iron, cobalt, and nickel. The metal is generally prepared from arsenious oxide, or white arsenic, one of its compounds with oxygen. It has a bright-gray lustre ; it tarnishes in the air by oxidation ; its weight is about five and a half times greater than water; when heated to dull redness it rises into vapor without first fusing, and its vapor emits a strong odor of garlic. Metallic arsenic is not of great importance in the arts. An alloy of copper and arsenic produces a brilliant gray metal used in the manufacture of buttons. A compound of arsenic and copper forms a bright substance largely used as a pigment under the name of Schele'sgreen. It was formerly much employed by paper-stainers in the manufacture of wall paper. Sheep-dipping mixtures consist of a compound of arsenic and soda dissolved in a large quantity of water, together with soap and sulphur. Arsenic has long been used as a medicine, and is used in some countries with the belief that it improves the complexion, but it is a dangerous poison, toeing fatal to adults in doses of from 2 to 3 grains. No effective antidote to it is known.