CHEVREUL

chevreul, michel eugene (1786-1889), french chemist, was born, on the 31st of august 1786, at angers, where his father was a physician. at about the age of seventeen he went to paris and entered l.n. vauquelin's chemical laboratory, afterwards becoming his assistant at the natural history museum in the jardin des plantes. in 1813 he was appointed professor of chemistry at the lycee charlemagne, and subsequently undertook the directorship of the gobelins tapestry works, where he carried out his researches on colour contrasts (_de la loi du contraste simultane des couleurs_, 1839). in 1826 he became a member of the academy of sciences, and in the same year was elected a foreign member of the royal society of london, whose copley medal he was awarded in 1857. he succeeded his master, vauquelin, as professor of organic chemistry at the natural history museum in 1830, and thirty-three years later assumed its directorship also; this he relinquished in 1879, though he still retained his professorship. in 1886 the completion of his hundredth year was celebrated with public rejoicings; and after his death, which occurred in paris on the 9th of april 1889, he was honoured with a public funeral. in 1901 a statue was erected to his memory in the museum with which he was connected for so many years. his scientific work covered a wide range, but his name is best known for the classical researches he carried out on animal fats, published in 1823 (_recherches sur les corps gras d'origine animale_). these enabled him to elucidate the true nature of soap; he was also able to discover the composition of stearin and olein, and to isolate stearic and oleic acids, the names of which were invented by him. this work led to important improvements in the processes of candle-manufacture. chevreul was a determined enemy of charlatanism in every form, and a complete sceptic as to the "scientific" psychical research or spiritualism which had begun in his time (see his _de la baguette divinatoire, et des tables tournantes_, 1864). chevron (fr. from _chevre_, a goat), in architecture, the beams or rafters in the roofs of a building, meeting in an angle with a fancied resemblance to the horns of a butting goat; in heraldry a bent bar on a shield, used also as a distinguishing badge of rank on the sleeves of non-commissioned officers in most armies and navies and by police and other organized bodies wearing uniform, and as a mark of good conduct in the army and navy. chevron is also an architectural term for an inflected ornament, called also "zig-zag," found largely in romanesque architecture in france, england and sicily. it is one of the most common decorations found in the voussoirs of the norman arch, and was employed also on shafts, as in the cloisters of monreale near palermo, those of st paul outside rome, and many churches in germany. its earliest appearance was in the tomb of agamemnon at mycenae, where the shafts flanking the entrance doorway have nine decorative chevron bands; in this case there is no doubt it was derived from the metal casing of the early wood columns.