1791 in science

The year 1791 in science and technology involved some significant events.

Biology

 * Jean Baptiste François Pierre Bulliard begins publication of Histoire des champignons de la France, a significant text in mycology.
 * Luigi Galvani publishes his discoveries in "animal electricity" (Galvanism).

Chemistry

 * Nicolas Leblanc patents the Leblanc process for the production of soda ash (sodium carbonate) from common salt (sodium chloride).
 * The element Titanium is discovered included in ilmenite in Cornwall, England, by local amateur geologist Rev. William Gregor.

Medicine

 * May 7 – Irish surgeon Samuel Croker-King first describes his trepanning device.

Metrology

 * March – In France, the National Constituent Assembly accepts the recommendation of its Commission of Weights and Measures that the nation should adopt the metric system.

Physics

 * Pierre Prévost shows that all bodies radiate heat, no matter how hot or cold they are.

Technology

 * James Rumsey is granted a patent related to fluid power engineering, in England.

Publications

 * Sir John Sinclair's Statistical Account of Scotland begins publication, introducing the term Statistics into English.

Awards

 * Copley Medal: James Rennell; Jean-André Deluc

Births

 * March 20 – John Farey, English mechanical engineer and technical writer (died 1851)
 * April 9 – George Peacock, English mathematician (died 1858)
 * April 27 – Samuel F. B. Morse, American inventor (died 1872)
 * July 13 – Allan Cunningham, English botanist and explorer (died 1839)
 * July 27 – Jean-Nicolas Gannal, French pharmacist, chemist and inventor (died 1852)
 * September 4 – Robert Knox, Scottish anatomist (died 1862)
 * September 22 – Michael Faraday, English chemist and physicist (died 1867)
 * September 23 – Johann Franz Encke, German astronomer (died 1865)
 * December 26 – Charles Babbage, English mathematician and inventor of computing machines (died 1871)

Deaths

 * July 24 – Ignaz von Born, Hungarian metallurgist (born 1742)
 * Date unknown – Maria Petraccini, Italian anatomist and physician (died 1759)