1838 in science

• Friedrich Wilhelm Bessel makes the first accurate measurement of distance to a star, 61 Cygni, using parallax. Thomas Henderson (Alpha Centauri) and Friedrich Georg Wilhelm Struve (Vega) announce their measurements using parallax shortly afterwards.
• Claude Servais Mathias Pouillet makes the first quantitative measurements of the heat emitted by the Sun.
• Peter Andreas Hansen publishes a revision of the lunar theory, Fundamenta nova investigationis orbitae verae quam luna perlustrat.

• May 9 – Royal Agricultural Society of England established.
• Proteins discovered by Gerardus Johannes Mulder{{cite journal|first=G. J.|last=Mulder|journal=Natuur- en Scheikundig Archief|volume=6|title=Over Proteine en hare Verbindingen en Ontledingsproducten|year=1838|pages=87–162}} and named by Jöns Jakob Berzelius.{{cite journal|title=The Origin of the Word Protein|first=Hubert Bradford|last=Vickery|journal=Yale Journal of Biology and Medicine|pages=387–93|volume=22|year=1950|pmc=2598953|pmid=15413335|issue=5}}
• Matthias Schleiden discovers that all living plant tissue is composed of cells.
• Andrew Smith begins publication of Illustrations of the Zoology of South Africa.

• Bulat steel alloy developed by Pavel Petrovich Anosov.
• Electrotyping is invented by Moritz von Jacobi in Russia.{{cite journal|last=Heinrich |first=Herbert |title=The Discovery of Galvanoplasty and Electrotyping |journal=Journal of Chemical Education |pages=565–575 |url=http://www.jce.divched.org/journal/issues/1938/Dec/jceSubscriber/JCE1938p0565.pdf |accessdate=2012-06-21 |date=December 1938 |doi=10.1021/ed015p565 |volume=15 |issue=12 |bibcode=1938JChEd..15..565H }}{{dead link|date=June 2017 |bot=InternetArchiveBot |fix-attempted=yes }}

• August 18 – The United States Exploring Expedition under U.S. Navy Lieutenant Charles Wilkes sets sail for a four-year circumnavigation westabout.
• In Australia, Charles Sturt proves that the Hume and Murray are the same river.

• Augustus De Morgan introduces the term 'mathematical induction'.{{cite book|first=Tony|last=Crilly|title=50 Mathematical Ideas you really need to know|location=London|publisher=Quercus|year=2007|isbn=978-1-84724-008-8|page=69}}
• S. D. Poisson publishes Recherches sur la probabilité des jugements en matière criminelle et en matière civile, containing his work on probability theory and introducing Poisson distribution.

• Jean Esquirol publishes Des maladies mentales considerées sous le rapport médicale, hygiènique et médico-legal in Paris. This includes the first description of what will later become known as Down syndrome.{{cite web|title=Down's syndrome|url=http://www.whonamedit.com/synd.cfm/322.html|work=Whonamedit?|accessdate=2011-04-13}}
• John Gorrie experiments with cooling the hospital wards of malarial patients in Apalachicola, Florida.{{cite book|authorlink=James Burke (science historian)|first=James|last=Burke|title=Connections|location=London|publisher=Macmillan|year=1978|isbn=978-0-333-24827-0|page=239}}

• January 6/11 – Samuel Morse first publicly demonstrates the electrical telegraph, at Morristown, New Jersey.
• April 4–22 – The paddle steamer SS Sirius (1837) makes the Transatlantic Crossing to New York from Cork, Ireland, in eighteen days, though not using steam continuously.{{cite web|title=Steamship Curaçao|url=http://www.vrcurassow.com/2dvrc/sscuracao/sscuracao.html|accessdate=2011-02-02| archiveurl= https://web.archive.org/web/20101224202256/http://vrcurassow.com/2dvrc/sscuracao/sscuracao.html| archivedate= 24 December 2010 | url-status= live}}
• April 8–23 – Isambard Kingdom Brunel's paddle steamer {{SS|Great Western}} (1838) makes the Transatlantic Crossing to New York from Avonmouth, England, in fifteen days, inaugurating a regular steamship service.{{cite web|url=http://www.icons.org.uk/theicons/icons-timeline/1820-1840 |title=Icons, a portrait of England 1820-1840 |accessdate=2007-09-12 |archiveurl=https://web.archive.org/web/20070922055840/http://www.icons.org.uk/theicons/icons-timeline/1820-1840 |archivedate=22 September 2007 |url-status=dead }}
• Liverpool-built barque Ironsides becomes the first large ocean-going iron ship.{{cite book|first=John|last=Grantham|title=On Iron Ship Building|location=London|publisher=Lockwood|edition=2nd|year=1859|pages=13–14}}
• William Barnett obtains a United Kingdom patent for an internal combustion engine, the first with compression of the gas/air mixture in the cylinder.Patent No. 7615, Obtaining motive power from inflammable gases by compression and explosion.{{cite book|first=Dugald|last=Clerk|authorlink=Dugald Clerk|title=Gas and Oil Engines|url=https://archive.org/details/gasoilenginecler00clerrich|location=London|publisher=Longman Green & Co|year=1897}}
• David Bruce, Jr., invents the Pivotal Typecaster, which replaces hand typecasting in printing.
• Boris Semyonovich Yakobi invents electrotyping, which is used in printing and reproduction of art objects.{{cite journal|last=Heinrich|first=Herbert|title=The Discovery of Galvanoplasty and Electrotyping|journal=Journal of Chemical Education|date=December 1938|pages=566–575|volume=15|issue=12}}
• The first screw-pile lighthouse is built by Alexander Mitchell on Maplin Sands in the Thames Estuary.
• Charles Wheatstone originates the stereoscope.

• A statue of English chemist and physicist John Dalton (in marble by Sir Francis Chantrey) is erected in Manchester during the scientist's lifetime.

• Copley Medal: Carl Friedrich Gauss; Michael Faraday{{cite web |title=Copley Medal {{!}} British scientific award |url=https://www.britannica.com/science/Copley-Medal |website=Encyclopedia Britannica |accessdate=22 July 2020 |language=en}}
• Wollaston Medal: Richard Owen

• January 5 – Camille Jordan (died 1922), French mathematician.
• January 29 – Edward W. Morley (died 1923), American chemist.
• February 18 – Ernst Mach (died 1916), Austrian physicist.
• March 3 – George William Hill (died 1914), American astronomer.
• March 12 – William H. Perkin (died 1907), English chemist.
• March 15 – Alice Cunningham Fletcher (died 1923), Cuban-born American ethnologist, anthropologist and social scientist.
• April 8 – Ferdinand von Zeppelin (died 1917), German founder of the Zeppelin airship company.
• April 16 – Ernest Solvay (died 1922), Belgian chemist.
• April 18 – Paul-Émile Lecoq de Boisbaudran (died 1912), French chemist.
• April 21 – John Muir (died 1914), Scottish-born American naturalist.
• May 6 – Alexandra Smirnoff (died 1913), Finnish pomologist.
• June 4 – John Grigg (died 1920), New Zealand astronomer.
• July 19 – Joel Asaph Allen (died 1921), American zoologist.
• August 6 – George James Symons (died 1900), English meteorologist.
• December 12 – Sherburne Wesley Burnham (died 1921), American astronomer.

• March 16 – Nathaniel Bowditch (born 1773), American mathematician.
• April 6 – José Bonifácio de Andrada (born 1763), Brazilian statesman and mineralogist.
• May 11 – Thomas Andrew Knight (born 1759), English horticulturalist.
• July 5 – Jean Marc Gaspard Itard (born 1774), French otorhinolaryngologist.
• August 21 – Adelbert von Chamisso (born 1781), German botanist.
• September 1 – William Clark (born 1770), American explorer.
• September 27 – Bernard Courtois (born 1777), French chemist.
• October 1 – Charles Tennant (born 1768), Scottish chemist and industrialist.

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Category:19th century in science

Category:1830s in science