1851 in science

The year 1851 in science and technology involved some significant events, listed below.

Astronomy

February – First public exhibition of a Foucault pendulum, at the Meridian of the Paris Observatory, demonstrating the Earth's rotation. A few weeks later Foucault installs one at the Panthéon.{{cite book|first=William|last=Tobin|title=The Life and Science of Léon Foucault, the Man who Proved the Earth Rotates|publisher=Cambridge University Press|year=2003|isbn=0-521-80855-3}}

File:1851 07 28 Berkowski.jpg: the first correctly exposed photograph of a solar eclipse, using the daguerreotype process.]]

July 28 – Solar eclipse of July 28, 1851: Total solar eclipse. The first correctly exposed photograph, a daguerrotype, of the solar corona is made during the total phase of the eclipse by Berkowski at Koenigsberg Observatory in Prussia.{{cite journal|title=On the Berkowski daguerreotype (Königsberg, 1851 July 28): the first correctly-exposed photograph of the solar corona|last1=Schielicke|first1=Reinhard|last2=Wittmann|first2=Axel D.|journal=Acta Historica Astronomiae|volume=25|pages=128–147|year=2005|bibcode=2005AcHA...25..128S}} Astronomers Robert Grant and William Swan (of the United Kingdom) and Karl Ludwig von Littrow (of Austria) observe this eclipse and determine that solar prominences are part of the Sun because the Moon is seen to cover and uncover them as it moves in front.{{cite web|url=http://www.mreclipse.com/Totality2/TotalityApH.html|first1=Mark|last1=Littmann|first2=Ken|last2=Willcox|first3=Fred|last3=Espenak|title=Chronology of Discoveries about the Sun|work=MrEclipse.com|year=1999|accessdate=2012-06-06}}
October 24 – Ariel and Umbriel, moons of Uranus, were discovered by William Lassell.Astronomical Journal 2(33):p. 70 (1851).
The William Brydone Jack Observatory is completed at Fredericton, New Brunswick.

March – English sculptor Frederick Scott Archer makes public the wet plate collodion photographic process.The Chemist March 1851.
Julius Pintsch produces Pintsch gas.
Charles-Adolphe Wurtz produces compound ureas.

Eugène Prouhet first applies the Thue–Morse sequence to number theory.
Bernhard Riemann provides a proof of Green's theorem in his inaugural dissertation.{{cite book|first=Bernhard|last=Riemann|url=https://archive.org/details/bub_gb_PpALAAAAYAAJ|title=Grundlagen für einen allgemeine Theorie der Functionen einer veränderlichen complexen Grösse [Basis for a general theory of functions of a variable complex quantity]|location=Göttingen (Germany)|publisher=Adalbert Rente|year=1867|pages=8–9}}

The Royal Marsden is established as the Free Cancer Hospital by surgeon William Marsden in London, the world's first specialist cancer hospital.
The Keratometer is invented by the German physiologist Hermann von Helmholtz.

Hippolyte Fizeau carries out the Fizeau experiment to measure the relative speeds of light in moving water.{{cite journal|last=Fizeau|first=H.|title=Sur les hypothèses relatives à l'éther lumineux|journal=Comptes rendus de l'Académie des sciences|location=Paris|volume=33|year=1851|pages=349–355|url=http://gallica.bnf.fr/ark:/12148/bpt6k29901/f351.chemindefer}}

November 13 – First protected submarine telegraph cable laid, across the English Channel.
William Armstrong introduces the weight-loaded hydraulic accumulator.{{cite book|first=Ian|last=McNeill|title=Hydraulic Power|location=London|publisher=Longman|year=1972|isbn=0-582-12797-1}}

Copley Medal: Richard Owen{{cite web |title=Copley Medal {{!}} British scientific award |url=https://www.britannica.com/science/Copley-Medal |website=Encyclopedia Britannica |accessdate=23 July 2020 |language=en}}
Wollaston Medal for geology: Adam Sedgwick

January 19 – Jacobus Kapteyn (died 1922), Dutch astronomer.
February 15 – Spiru Haret (died 1912), Romanian mathematician, astronomer and politician.
March 16 – Martinus Beijerinck (died 1931), Dutch microbiologist and botanist.
April 12 – E. Walter Maunder (died 1928), English astronomer.
July 8 – Arthur Evans (died 1941), English archaeologist.
July 20 – Arnold Pick (died 1924), Jewish Czech neurologist.
August 3 – George FitzGerald (died 1901), Irish mathematician.
September 21 – Fanny Searls (died 1939), American doctor and botanist.{{cite journal |last=Tiehm |first=Arnold |title=Fanny Searls (1851-1939)| journal=Brittonia |volume=37 |number=1 |year=1985 |page=41| doi=10.1007/BF02809668|s2cid=87755152}}
September 23 – Ellen Hayes (died 1930), American mathematician and astronomer.