HAUY, RENE JUST (1743-1822), French mineralogist, was born at St. Just, Oise, on Feb. 28, 1743. An accident directed his attention to crystallography. Happening to let fall a specimen of calcareous spar, he was led by examination of the fragments to make experiments which resulted in the statement of the geometri cal law of crystallization associated with his name (see CRYSTAL LOGRAPHY). The value of this discovery, the mathematical theory of which is given by flatly in his Traite de anineralogie, was im mediately recognized, and when communicated to the Academy, it secured for its author a place in that society. Haiiy's name is also known for the observations he made in pyro-electricity. When the Revolution broke out, he was saved by the intercession of E. Geoffroy Saint-Hilaire. In 1802, under Napoleon, he became pro fessor of mineralogy at the museum of natural history, but was deprived at the Restoration. He died in Paris on June 3, 1822.
Among his numerous works may be mentioned Tableau comparatif des resultats de la cristallographie, et de l'analyse chimique relative meat a la classification des mineraux (1809) ; Traite des pierres pre cieuses (1817) ; Traite de cristallographie (2 vols., 1822). He also con tributed papers, of which loo are enumerated in the Royal Society's catalogue, to various scientific journals, especially the Journal de physique and the Annales du Museum d'Histoire Naturelle.