The New International Encyclopædia/Vermilion

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VERMILION (OF., Fr. vermillion, from vermeil, bright-red, from Lat. vermiculus, little worm, kermes-insect, from which crimson or carmine was obtained, diminutive of vermis, worm). A name applied to cinnabar, or native mercuric sulphide, but more generally to the artificial sulphide used as a pigment, the mineral not being of sufficient purity to be used directly as a pigment. The vermilion of commerce was formerly prepared by heating together mercury and sulphur in an iron pan with constant stirring. A more modern process consists in bringing mercury, sulphur, and an aqueous solution of potassium hydroxide together in a revolving drum and heating to about 46° C. (115° F.), when the mixture gradually assumes a red color. It is said that about 85 pounds of mercury are required to produce 100 pounds of vermilion. Vermilion is a permanent pigment, and may be used with water or oil, but cannot be used in enamel, as it volatilizes at a red heat. It possesses great body, weight, and opacity. Numerous pigments consisting of aniline colors thrown on a lead body, such as the oxide or carbonate, have largely taken the place of the true vermilion as a pigment, especially as they have a permanent red color, stand exposure fairly well, and change to a lighter color with age instead of a darker, as is the case with vermilion.