HAIDINGER, WILHELM KARL, RITTER VON 1871), Austrian mineralogist, geologist and physicist, was born at Vienna on Feb. 5, 1795. His father, Karl Haidinger, contributed largely to the development of mineralogical science in the latter half of the i8th century. He studied under Mohs at Graz and Freiberg, spent some years in Edinburgh, and made a tour of northern Europe. He then became scientific director of his brothers' porcelain works, and then succeeded Mohs at Vienna as counsellor of mines. His lectures on mineralogy were printed as Handbuch der bestimmenden Mineralogie (1845 ; tables, 1846) . He was director of the imperial geological institute for 17 years, and held many other appointments. In physics he was the dis coverer of the interesting optical appearances which have been called after him "Haidinger's brushes." He died at Dornbach near Vienna on March 19, 1871.
Haidinger wrote many other works on mineralogy. Some of his papers will be found in the Transactions of the Royal Society of Edinburgh (vol. x.) and of the Wernerian Society (1822-23), Edin burgh Phil. Journal, Brewster's Journal of Science, and Poggendorf's Annalen.