After completing his secondary schooling Bougainville was influenced by d'Alembert and he wrote Traité du calcul -intégral in 1752. This extended de l'Hôpital's book, written more that half a century earlier, to cover the integral calculus and also updated the differential calculus providing an up-to-date text. George writes in :-
He bought such clarity and order to the subject, as well as incorporating new work, that he achieved immediate recognition. The Académie des Sciences noticed the work in January 1753. It was published the following year ...This work led to Bougainville's election to the Royal Society of London in 1756. Also in 1756 he published a second volume but this marks the end rather than the beginning of his career as a mathematician.
Bougainville then gave up mathematics. He had joined the army in 1754 and now, in 1756 :-
... he went to Canada as aide-de-camp to Gen. Louis-Joseph de Montcalm and distinguished himself against the British in the French and Indian War.Back in France he left the army in 1763 and joined the navy. In 1764 sailed from France out into the Atlantic and sailed down the coast of South America to the Falkland Islands where he established a French colony.
In 1766 the French government commissioned Bougainville to sail round the world. No Frenchman had ever sailed round the world, but many islands had been discovered in the Pacific and many European nations joined in the search for new lands. The Englishman William Dampier had discovered New Hanover, New Britain, and New Ireland while in command of a Royal Navy ship. In 1722 the Dutchman Jacob Roggeveen crossed the Pacific from east to west and discovered Easter Island, more of the Tuamotu Archipelago, some of the Society group, and some of the Samoan islands. The Englishman John Byron was sent in 1765 to try to find a southern continent which many believed must exist. He did not find a continent but he did find more of the Tuamotus and the southern Gilberts.
Bougainville had an open mind on the question of a southern continent. On the one hand he declared:-
... that it is difficult to conceive such a number of low islands and almost drowned lands without a continent near them ...But one the other hand he found it hard to believe that a southern continent existed for surely it would have been discovered by the earlier explorers:-
... if any considerable land existed hereabouts we could not fail meeting with it.In November 1766, accompanied by naturalists and other scientists, Bougainville sailed from Nantes in the frigate La Boudeuse. He put into Brest for repairs and set off again on 5 December. He took much the same route via the Falkland Islands as he had when he set out in 1764. He called in at Rio de Janeiro and there met up with his supply ship. On that ship was the botanist Commerson who had discovered a shrubby climbing deciduous plant whose flowers were insignificant but were surrounded by brilliant coloured purple-red papery bracts that lasted for a long time. He named the plant bougainvillea in honour of Bougainville.
The two ships left Rio de Janeiro in July 1767 on their way to Montevideo. They left the River Plate in November 1767 and sailed through the Strait of Magellan in December. Bougainville went northwest through the South Pacific and by the end of March 1768 he discovered islands in the archipelago of Tuamoto, now French Polynesia. Continuing he landed on Tahiti which he found had been discovered eight months earlier in 1767 by the Englishman Samuel Wallis. Bougainville then sailed west reaching what is now named Bougainville reef, just to the east of the Great Barrier reef. At this point he turned north, where he came very close to sighting Australia, reaching the Louisiade Archipelago, an island group of Papua New Guinea, 200 km southeast of the island of New Guinea. Bougainville named the Archipelago after Louis XV of France.
Continuing north he discovered two of the Treasury Islands. Then he sailed along the west coast of Choiseul island, in the western Solomon Islands, southeast of (now named) Bougainville Island across the (now named) Bougainville Strait. He then sailed for three days along the coast of the (now named) Bougainville Island which he described as :-
... a new coast which is of astonishing height.Bougainville continued on to New Britain but, because his men were by then suffering from scurvy and his ships needed refitting, he stopped at Buru in the Moluccas in September 1768. There he found a :-
... species of wild cat that carries her young in a pocket below her belly.At Batavia (now Jakarta) in Java, Bougainville stopped again before returning to Saint-Malo, in Brittany, in March 1769.
This voyage made Bougainville the first Frenchman to sail round the World. He made systematic astronomical observations on his voyage which provided important navigation charts to later explorers. However :-
It has been said by Frenchmen that, in spite of his mathematical abilities, Bougainville was no great navigator.This seems a harsh judgement for someone who achieved so much on his voyage. Perhaps a quote from Bougainville himself, taken from  which describes his round-the-world voyage in detail, shows most clearly his attitude to exploration:-
But geography is a science of facts: one cannot speculate from an armchair without the risk of making mistakes which are often corrected only at the expense of the sailors.Bougainville received great acclaim after he returned to France. He was promoted in both the navy and the army. In 1772 he was appointed secretary to Louis XV. He married in 1780 and he had four children. From 1779 to 1782 he served as commodore in operations of the French fleet off North America, supporting the American Revolution. On 12 April 1782, after a French defeat off Martinique, he was court-martialled.
During the French Revolution, he escaped the massacres of Paris in 1792 despite his well known Royalist views. He settled on his estate in Normandy and later Napoleon made him a senator, a count, and a member of the Legion of Honour.
Article by: J J O'Connor and E F Robertson