1911 Encyclopædia Britannica/Des Cloizeaux, Alfred Louis Olivier Legrand
DES CLOIZEAUX, ALFRED LOUIS OLIVIER LEGRAND (1817–1897), French mineralogist, was born at Beauvais, in the department of Oise, on the 17th of October 1817. He became professor of mineralogy at the École Normale Supérieure and afterwards at the Musée d’Histoire Naturelle in Paris. He studied the geysers of Iceland, and wrote also on the classification of some of the eruptive rocks; but his main work consisted in the systematic examination of the crystals of numerous minerals, in researches on their optical properties and on the subject of polarization. He wrote specially on the means of determining the different felspars. He was awarded the Wollaston medal by the Geological Society of London in 1886. He died in May 1897. His best-known books are Leçons de cristallographie (1861); Manuel de minéralogie (2 vols., Paris, 1862, 1874 and 1893).