1809 in science

List of years in science (table)
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The year 1809 in science and technology involved some significant events, listed below.

Astronomy

• Carl Friedrich Gauss publishes Theoria motus corporum coelestium in sectionibus conicis solem ambientum in Hamburg, introducing the Gaussian gravitational constant and containing an influential treatment of the least squares method.
• S. D. Poisson publishes Sur les inégalités séculaires des moyens mouvements des planètes and Sur la variation des constantes arbitraires dans les questions de mécanique in the Journal of the École Polytechnique, extending Lagrange's theory of planetary orbits.

Biology

• Jean-Baptiste Lamarck publishes Philosophie Zoologique, outlining his theory of evolution.

Geology

• William Maclure publishes the first geological map of the United States with accompanying memoir.

Mathematics

• Louis Poinsot describes the two remaining Kepler-Poinsot polyhedra.

Medicine

• December 25 – American physician Ephraim McDowell performs the world's first ovariotomy, the removal of an ovarian tumor.
• Philippe Pinel publishes accounts of what would later be regarded as schizophrenia.

Technology

• February 11 – Robert Fulton patents the steamboat in the United States.
• Samuel Thomas von Sömmerring invents a water voltameter electrical telegraph.
• William Hyde Wollaston invents the reflecting goniometer.

Awards

• Copley Medal: Edward Troughton

Births

• January 4 – Louis Braille (died 1852), inventor.
• February 12 – Charles Darwin (died 1882), naturalist.
• February 15 – Cyrus McCormick (died 1884), inventor.
• February 21 – Carl Ernst Bock (died 1874), physician and anatomist.
• April 15 – Hermann Günther Grassmann (died 1877), mathematician.
• April 20 – James David Forbes (died 1868), physicist, glaciologist and seismologist.
• August 29 – Oliver Wendell Holmes, Sr. (died 1894), physician and writer.
• November 22 – Bénédict Morel (died 1873), psychiatrist.
• Date unknown
  • Marie Durocher (died 1893), physician.
  • William Lobb (died 1864), plant collector.

Deaths

• May 17 – Leopold Auenbrugger (born 1722), Austrian physician.
• August 18 – Matthew Boulton (born 1728), English mechanical engineer.
• October 11 – Meriwether Lewis (born 1774), American explorer.
• December 16 – Antoine François, comte de Fourcroy (born 1755), French chemist.
• December 29 – Thomas Barker (born 1722), English meteorologist.