Antonio De Ulloa, a Spanish naval officer, born in Seville, Jan. 12, 1716, died in the Isla de Leon, near Cadiz, July 3, 1795. He was educated for the navy, became in 1733 a member of the royal marine guards, and in 1735 a lieutenant, when he was sent to South America with the French academicians who were commissioned to measure a degree of the meridian at the equator. From this he was called away to assist in putting the coast in a state of defence against Lord Anson's expedition. In October, 1744, he embarked for Europe, but was captured by the British, and carried to London, where his scientific friends obtained his liberty, and made him a member of the royal society. On his return to Spain in 1746 he wrote a history of the expedition, the scientific portion being written by his companion, Jorge Juan (4 vols., Madrid, 1748; translated into English, " A Voyage to South America," 2 vols., London, 1772; 4th ed., 1800). In 1755 he went a second time to America, and after the peace of 1763 was made governor of Louisiana, where he arrived in March, 1766. An insurrection obliged him to leave the colony, and he returned to Europe. In 1772 he published a volume of essays on the natural history and antiquities of America, and in 1778 "Observations of a Solar Eclipse made at Sea." He was now a lieutenant general in the naval service, and was appointed to the command of a squadron intended to capture off the Azores an English merchant fleet heavily laden, and afterward to sail to Havana and join an expedition fitting out against Florida. Absorbed in his scientific investigations, Ulloa forgot to open his sealed orders, and after cruising about for two months without success returned.

He was tried in 1780 by a court martial demanded by himself, and, though acquitted, never again engaged in active service.