HOUDAN, Lue du, French hydrographer, born in Rennes in 1811; died in Paris in i846. He entered the navy, and was a lieutenant in the French fleet that blockaded Buenos Ayres in 1840-'3. He was sent several times to make hydrographic observations through the country, was in Buenos Ayres at the outbreak of the riots that desolated that city in April, 1843, and barely escaped death. Returning to France in December of the same year, he published" Histoire et vue pittoresques des sites de Buenos Ayres" (Paris, 1844); "Le systeme pluvial dans l'Amerique du Sud" (1844); "Le tours du Parana jusqu'a sa junction avec le Paraguay" (2 vols., 1845, with charts); and "Releve hydrographique de l'Uruguay" (2 vols., 1845, with charts). After his death appeared "La situation politique de l'Amerique du Sud, et de l'avenir de ces pays" (Paris, 1846); "Releve hydrographique du tours du Paraguay" (1846); and "Hydrographie et geodesie de l'Amerique du Sud" (1847).