1809 births

Count Antoine Hector Thésée Treuille de Beaulieu (7 May 1809 – 24 July 1885) was a French General of the 19th century, who developed the concept of rifled guns in the French Army. He studied the subject of rifling between 1840, particularly in the famous Manufacture d'armes de Châtellerault, and 1852. Following a request by Napoleon III in 1854 to develop such a weapon, the de Beaulieu system was adopted by the French Army. It consisted in cutting six grooves inside the bore of a muzzle-loading cannon, and to use shells equipped with six lugs which would engage the grooves. This development was paralleled by that of the Armstrong gun in Great Britain (adopted in 1858 by the British Army).
About the same time he developed a pinfire falling-block breech-loading carbine (mousqueton) for the Cent-gardes Squadron which was a bit ahead of its time in using a metallic cartridge and is very unusual (for a single-shot weapon) in that it fires from an open bolt.These developments led to the introduction of the La Hitte system in 1858, a fully integrated system of muzzle-loading rifled guns. The Beaulieu 4-pounder rifled field-gun was adopted by the French Army in 1858, where it replaced the canon-obusier de 12, a smoothbore cannon using shells which was much less accurate and shorter-ranged.The Beaulieu rifled artillery was first used in Algeria, and then in the Franco-Austrian War in Italy in 1859.In 1842 he invented a prototype of the modern muzzle brake and had it tested in 1862.

Jules Germain Francois Maisonneuve (10 December 1809 – 9 April 1897) was a French surgeon and student of Guillaume Dupuytren. Maisonneuve is notable as the first surgeon to explain the role of external rotation in the production of ankle fractures. The eponymously named Maisonneuve fracture describes a specific fibular fracture.

Félix-Victor Mauvais (or Victor Mauvais; March 7, 1809 – March 22, 1854) was a French politician and astronomer. He was born in the small village of Maîche in the department of Doubs and died in Paris.
In 1836 he went to the Observatoire de Paris as a student astronomer. He worked at the Bureau des Longitudes from 1843 to 1854, working on meteorology. He was elected to the Académie des Sciences in 1843. He won the Lalande Prize in 1843 for the discovery of comet C/1843 J1. He also discovered comets C/1844 N1 and C/1847 N1.
In politics, he served as a leftist member of the National Assembly from 1848 to 1849.
On March 2, 1854, the Observatory and the Bureau des Longitudes were separated, which obliged Mauvais to leave this institution. Very affected by this, he fell ill and committed suicide a few weeks later.

Laurent-Guillaume de Koninck (3 May 1809 – 16 July 1887) was a Belgian palaeontologist and chemist, born at Leuven.
He studied medicine in the university of his native town, and in 1831 he became assistant in the chemical schools. He pursued the study of chemistry in Paris, Berlin and Gießen, and was subsequently engaged in teaching the science at Ghent and Liège. In 1856 he was appointed professor of chemistry in the Liège University, and he retained this post until the close of his life.About the year 1835 he began to devote his leisure to the investigation of the Carboniferous fossils around Liège, and ultimately he became distinguished for his researches on the palaeontology of the Palaeozoic rocks, and especially for his descriptions of the molluscs, brachiopods, crustaceans and crinoids of the Carboniferous limestone of Belgium. In recognition of this work the Wollaston medal was awarded to him in 1875 by the Geological Society of London, and in 1876 he was appointed professor of palaeontology at Liège. In 1882, he was elected as a member to the American Philosophical Society.He was awarded the Clarke Medal by the Royal Society of New South Wales in 1886.Publications:

Eléments de chimie inorganique (1839)
Description des animaux fossiles qui se trouvent dans le terrain Carbonifère de Belgique (1842–1844, supp. 1851)
Recherches sur les animaux fossiles (1847, 1873)See Notice sur LG de Koninck, by E Dupont; Annuaire de l'Aced. roy. de Belgique (1891), with portrait and bibliography.

Pierre-Joseph van Beneden FRS FRSE FGS FZS (19 December 1809 – 8 January 1894) was a Belgian zoologist and paleontologist.

René Waldeck-Rousseau (27 April 1809 Avranches, Manche – 17 February 1882 Nantes, Loire-Atlantique) was a French politician, father of Pierre Waldeck-Rousseau who was a statesman during the Third Republic.
During the 1848 Revolution, he was elected as a Republican deputy of Loire-Inférieure to the Constituent Assembly of April 1848 to May 1849. He then became mayor of Nantes, from 1870 to 1871 and a second time from 1872 to 1874.
With Jules Simon, Louis Blanc and others he sat on the commission appointed to inquire into the labour question during the Second Republic, making many important proposals, one of which, for the establishment of national banks, was partially realized in 1850. After the election of Louis Napoleon Bonaparte to the presidency he returned to his practice at the bar, and for some time after the coup d'état was in hiding to escape arrest.
He came back to political life in the crisis of 1870, when he became mayor of Nantes in August and took part to the proclamation of the Third Republic there on September 4. He shortly afterwards resigned municipal office in consequence of differences with his colleagues on the education question.

Louis Henri, comte de Gueydon (22 November 1809 – 1 December 1886) was a vice admiral in the French Navy, and the first governor of Algeria under the Third Republic.

Léon Martin Fourichon (10 January 1809, Thiviers – 24 November 1884, Paris) was a French naval officer, colonial administrator and politician.

Jules Baillarger, full name Jules Gabriel François Baillarger (25 March 1809 – 31 December 1890), was a French neurologist and psychiatrist.

Joseph-Pierre Borel d'Hauterive, known as Petrus Borel (26 June 1809 – 14 July 1859), was a French writer of the Romantic movement.