1819 in science

Astronomy and space science

• Johann Franz Encke computes the orbit of Comet Encke, identifying it as periodic.
• July 1 – Johann Georg Tralles discovers the Great Comet of 1819,. It is the first comet analyzed using polarimetry, by François Arago.

  Chemistry

• Joseph Bienaimé Caventou and Pierre Joseph Pelletier isolate the alkaloid brucine from Strychnos nux-vomica.

  Exploration

• February 19 – Captain William Smith in British merchant brig Williams sights Williams Point, the northeast extremity of Livingston Island in the South Shetlands, the first land discovered south of latitude 60° S.
• October 15 – Desolation Island in the South Shetland Islands of the Antarctic is discovered by Captain William Smith in the Williams.
• A British Arctic expedition under William Edward Parry comprising HMS Hecla and HMS Griper reaches longitude 112°51' W in the Northwest Passage, the furthest west which will be attained by any single-season voyage for 150 years.

  Geology

• G. B. Greenough publishes his book in London.

  Medicine

• August – René Laennec publishes De l’Auscultation Médiate ou Traité du Diagnostic des Maladies des Poumons et du Coeur in Paris, describing his invention of the stethoscope.
• English physician John Bostock publishes the first account of allergic rhinitis.

  Technology

• May 22 – leaves port at Savannah, Georgia on a voyage to become the first steamship to cross the Atlantic Ocean, although only a fraction of the trip is made under steam. The ship arrives at Liverpool, England, on June 20.
• Invention of the M1819 breech-loading flintlock using interchangeable parts by Captain John H. Hall of Harpers Ferry Armory in the United States.

  Institutions

• Cambridge Philosophical Society founded as a scientific society at the University of Cambridge in England.

  Awards

• Copley Medal: Not awarded

  Births

• March 24 – Friedrich Theodor von Frerichs, German medical pathologist.
• May 3 – Nikolai Annenkov, Russian botanist.
• June 5 – John Couch Adams, Cornish-born mathematician and astronomer.
• July 17 – Eunice Newton Foote, American physicist and women's rights campaigner.
• July 28 – Thomas Evans Blackwell, English civil and hydraulic engineer.
• August 9 – William T. G. Morton, American dentist.
• August 13 – George Gabriel Stokes, Irish-born mathematician and physicist.
• September 18 – Léon Foucault, French physicist.
• September 23 – Hippolyte Fizeau, French physicist.

  Deaths

• January – Elsa Beata Bunge, Swedish botanist.
• August 19 – James Watt, British inventor, mechanical engineer and mathematician.
• November 22 – John Stackhouse, English botanist.