1806 in science
- Publication begins in London of the Flora Graeca collected by John Sibthorp.
- Pierre André Latreille begins publication in France of Genera crustaceorum et insectorum, secundum ordinem naturalem ut familias disposita.
- November 20 – Humphry Davy presents the results of his researches in the electrolysis of water to the Royal Society of London.
- Louis Nicolas Vauquelin and Pierre Jean Robiquet isolate asparagine in crystalline form from asparagus juice in France, the first amino acid identified.
- Jean-Robert Argand introduces the Argand diagram.
- Adrien-Marie Legendre gives the first published application of the method of least squares, in a supplement to his Nouvelles méthodes pour la détermination des orbites des comètes.
- John Bell concludes publication of The Principles of Surgery in two volumes (1801–06). Its treatment of arterial surgery in particular ranks him as a founder of vascular surgery. His brother Charles Bell publishes Essays on The Anatomy of Expression in Painting.
- January 14 – Matthew Fontaine Maury, American oceanographer (died 1873)
- February 14 – Joseph-François Malgaigne, French surgeon (died 1865)
- April 9 – Isambard Kingdom Brunel, British civil engineer (died 1859)
- June 12 – John A. Roebling, German American bridge engineer (died 1869)
- June 27 – Augustus De Morgan, British logician (died 1871)
- November 21 – Alexander Henry Haliday, Irish entomologist (died 1870)
- December 11 – Otto Wilhelm Hermann von Abich, German geologist (died 1886)
- Luther V. Bell, American psychiatric physician (died 1862)
- April 5 – Benjamin Bell, Scottish surgeon (born 1749)
- June 23 – Mathurin Jacques Brisson, French zoologist (born 1723)
- August 3 – Michel Adanson, French botanist (born 1727)
- August 23 – Charles-Augustin de Coulomb, French physicist (born 1736)
- October 9 – Benjamin Banneker, African-American astronomer and surveyor (born 1731)
- Harris, Stephen (2007). The Magnificent Flora Graeca: How the Mediterranean Came to the English Garden. Oxford: Bodleian Library. ISBN 978-1-85124-306-8.
- Lack, H. Walter; Mabberley, David (1998). The Flora Graeca Story: Sibthorp, Bauer, and Hawkins in the Levant. Oxford University Press. ISBN 0-19-854897-4.
- Mawar, Granville (1999). Ahab's Trade: The Saga of South Seas Whaling. New York: St. Martin's Press. ISBN 0-312-22809-0.
- Jones, A. G. E. (1970). "Captain Abraham Bristow and the Auckland Islands" (PDF). Notes and Queries. 17 (10): 369–371. doi:10.1093/nq/17.10.369. Retrieved 2011-12-14.
- Crilly, Tony (2007). 50 Mathematical Ideas you really need to know. London: Quercus. ISBN 978-1-84724-008-8.
- Itard, Jean (2008). "Legendre, Adrien-Marie". Complete Dictionary of Scientific Biography. New York. Retrieved 2012-01-23.
- Baston, K. Grudzien (2004). "Bell, John (1763–1820)". Oxford Dictionary of National Biography. Oxford University Press. doi:10.1093/ref:odnb/2013. Retrieved 2011-04-06. (subscription or UK public library membership required)
- Penguin Pocket On This Day. Penguin Reference Library. 2006. ISBN 0-14-102715-0.