1803 in science

The year 1803 in science and technology involved some significant events.

Astronomy

 * April 26 – A meteorite shower falls on L'Aigle in Normandy; Jean Baptiste Biot demonstrates that it is of extraterrestrial origin.

Botany

 * Publication (posthumously) of André Michaux's Flora Boreali-Americana in Paris, the first flora of North America.
 * University of Tartu Botanical Gardens established.

Chemistry

 * January 1 – William Henry's formulation of his law on the solubility of gases first published.
 * September 3 – English scientist John Dalton starts using symbols to represent the atoms of different chemical elements.
 * October 21 – John Dalton's atomic theory and list of molecular weights first made known, at a lecture in Manchester.
 * William Hyde Wollaston discovers the chemical element rhodium.
 * Smithson Tennant discovers the chemical elements iridium and osmium.
 * Cerium is discovered in Bastnäs (Sweden) by Jöns Jakob Berzelius and Wilhelm Hisinger, and independently in Germany by Martin Heinrich Klaproth.
 * Claude Louis Berthollet publishes Essai de statique chimique in Paris.

Exploration

 * June 9 – Matthew Flinders completes the first known circumnavigation of Australia.

Mathematics

 * Gian Francesco Malfatti presents his conjecture regarding Malfatti circles.

Medicine

 * Jean Marc Gaspard Itard first recognises pneumothorax.
 * Dr Thomas Percival of Manchester publishes his Medical Ethics; or, a Code of Institutes and Precepts, Adapted to the Professional Conduct of Physicians and Surgeons, coining the expression medical ethics.

Meteorology

 * Luke Howard publishes the basis of the modern classification and nomenclature of clouds.

Technology

 * Robert Ransome invents the self-sharpening chilled cast-iron ploughshare in Ipswich, England.
 * The first Fourdrinier continuous papermaking machine is installed in Hertfordshire, England.

Transport

 * January 4 – William Symington demonstrates his Charlotte Dundas, the "first practical steamboat", in Scotland.
 * July 26 – The Surrey Iron Railway, a wagonway between Wandsworth and Croydon, is opened, being the first public railway line in England.
 * Thomas Telford begins work on construction of the Caledonian Canal and improving roads in Scotland.

Awards

 * Copley Medal: Richard Chenevix

Births

 * February 26 – Arnold Adolph Berthold, German physiologist (died 1861)
 * February 28 – Christian Heinrich von Nagel, German geometer (died 1882)
 * April 1 – Miles Joseph Berkeley, English cryptogamist (died 1889)
 * May 12 – Justus von Liebig, German chemist (died 1873)
 * May 24 – Charles Lucien Bonaparte, French naturalist (died 1857)
 * June 8 – Amalia Assur, Swedish dentist (died 1889)
 * July 31 – John Ericsson, Swedish-born mechanical engineer and inventor (died 1889)
 * October 3 – John Gorrie, American physician and inventor (died 1855)
 * October 6 – Heinrich Wilhelm Dove, Prussian physicist and climatologist (died 1879)
 * October 16 – Robert Stephenson, English railway engineer (died 1859)
 * November 29 – Christian Doppler, Austrian mathematician and discoverer of the Doppler effect (died 1853)
 * December 21 – Joseph Whitworth, English mechanical engineer (died 1887)
 * Choe Han-gi, Korean philosopher of science (died 1877)

Deaths

 * May 8 – John Joseph Merlin, Liège-born English inventor (born 1735)
 * October 14 – Ami Argand, Genevan physicist and chemist (born 1750)