YSABEAU, Alphonse Paul (ee-zah-bo), French naval officer, born in Dunkirk in 1811 ; died in Fort de France, Martinique, in December, 1848. He entered the navy as a midshipman in 1826, was promoted ensign in 1832 and lieutenant in 1837, sailed in the fleet that under Admiral De Mackau blockaded Buenos Ayres in 1840-'3, and was employed in hydrographic service in the river Plate. He made also a survey of the lower basin of the Parana. After a short sojourn in France he was attached to the station of Martinique, and died in Fort de France of yellow fever, he wrote "Rapport sur le bassin inferieur du Parana " (Paris, 1845); "Journal d'un temoin du siege de Buenos Ayres" (2 vols., 1846); and "Etudes sur les revolutions et les guerres civiles dans l'Amerique du Sud" (3 vols., Fort de France, 1848).