Louis Antoine De Bougainville, a French soldier and navigator, born Nov. 11, 1729, died Aug. 31, 1811. He entered the military service as aide-de-camp to Ohevert, and at the ago of 25 published a treatise on the integral calculus. In 1754 he went to London as secretary of the French embassy; in 1756 he served in Canada as aide-de-camp to Montcalm, after whose death he returned to France. In 1761 he displayed such courage in the campaign on the Rhine, that he received from the king two guns which he had taken from the enemy. Peace being concluded, he entered the navy, and undertook to establish a French colony in one of the Falkland islands. Compelled to relinquish this settlement on account of the objections of Spain, he sailed southward, passed through the straits of Magellan, and entered the South sea, which was still for the most part unexplored. He looked in vain for Davis's land, then steered through the Paumotu archipelago, where he discovered several yet unknown islands, arrived at Tahiti, April 6,1768, gave the name of Navigators' islands to the Samoan archipelago, and touched the part of the cluster which received a few years later from Capt. Cook the appellation of New Hebrides. He then reconnoitred the E. coast of Australia, doubled the Louisiade islands, passed the large Solomon's archipelago, which had not been visited since its discovery by Mendana, and put in at Port Praslin, New Ireland, where he repaired his ships.

He then took his course westward, discovering on his passage some small islands, and passing the N. shore of New Guinea. Finally he reached Booro, one of the Moluccas, where he procured a fresh supply of provisions, and in March, 1769, reached St. Malo, after a cruise of over two years. In 1771-'2 he published his Voyage autour du monde (2 vols., Paris), a very interesting account of his adventures, with a graphic description of the countries he had visited; it was immediately translated into English, and in 1783 into German. Bougainville had scarcely completed this work when he planned a voyage to the north pole; he wrote a memoir on the subject, proposing two distinct routes, and submitted it to the royal society of London, of which he had been admitted a member. In 1778, when the French took part in the American war of independence, Bougainville was appointed to the command of a ship of the line, and distinguished himself in all the engagements between the fleets of France and England. In the conflict in which De Grasse was defeated by Admiral Rodney, April 12, 1782, the Auguste, the ship commanded by Bougainville, suffered most severely, but maintained its station in the line to the last extremity; when no hope of retrieving the fortune of the day was left, by a judicious and decisive movement he succeeded in rescuing eight sail of his own immediate division, which he conducted safely to St. Eustace. Returning to France, he resumed his project of a voyage in the arctic seas, but received no encouragement, and finally left the naval service in 1790. In 1795 he was elected to the French institute, and subsequently became a member of the board of longitudes.

On the organization of the senate, he was made a member of that body by Napoleon, who also ennobled him.