1809 in science

The year 1809 in science and technology involved some significant events, listed below.

• 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.^[1]
• planetary orbits
  .

• Philosophie Zoologique, outlining his theory of evolution
  .
• Johann Heinrich Friedrich Link first describes Penicillium.^[2]

• William Maclure publishes the first geological map of the United States with accompanying memoir.^[1][3]

• Kepler-Poinsot polyhedra
  .

• December 25 –
  ovariotomy, the removal of an ovarian tumor.^[4]
• Philippe Pinel publishes accounts of what would later be regarded as schizophrenia.^[5]

• February 11 – Robert Fulton patents the steamboat in the United States.^[6][7]
• May 5 –
  Mary Kies becomes one of the first women granted a U.S. patent, for a technique of weaving straw hats with silk and thread.^[8]
• Samuel Thomas von Sömmerring invents a water voltameter electrical telegraph.^[1]
• William Hyde Wollaston invents the reflecting goniometer.

• Copley Medal: Edward Troughton^[9]

• January 4 –
  inventor
  .
• January 6 – Marie Durocher (died 1893), Brazilian physician.
• February 12 – Charles Darwin (died 1882), English naturalist.
• February 15 – Cyrus McCormick (died 1884), American inventor.
• February 21 –
  anatomist
  .
• April 7 – James Glaisher (died 1903), English meteorologist and balloonist.
• April 15 – Hermann Grassmann (died 1877), German mathematician.
• April 20 – James David Forbes (died 1868), Scottish physicist, glaciologist and seismologist.
• August 29 – Oliver Wendell Holmes Sr. (died 1894), American physician and writer.
• November 22 – Bénédict Morel (died 1873), French psychiatrist.
• Date unknown – William Lobb (died 1864), English plant collector.

• 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.