Editing 1821 in science

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{{Science year nav|1821}}

The year '''1821 in [[science]]''' and [[technology]] involved some significant events, listed below.

==Astronomy==
* [[Johann Franz Encke]] calculates that [[Comet Encke]] has a periodic [[orbit]], the second [[comet]] after [[Comet Halley]] for which this has been discovered.
* [[Alexis Bouvard]] detects irregularities in the orbit of [[Uranus]].

==Biology==
* Swedish [[mycologist]] [[Elias Magnus Fries]] begins publication of ''[[Systema Mycologicum]]'', a key work in the modern [[Taxonomy (biology)|taxonomy]] of [[mushroom]]s.
* [[William Jackson Hooker]] publishes ''[[Flora Scotica]]; or, A description of Scottish plants''.
* [[Prideaux John Selby]] begins publication of ''Illustrations of British Ornithology'', the first set of life-sized illustrations of British birds.

==Chemistry==
* [[John Kidd (chemist)|John Kidd]] describes the properties of the substance which he calls ''[[naphthalene|naphthaline]]''.<ref>{{cite journal|first=John|last=Kidd|year=1821|title=Observations on Naphthaline, a peculiar substance resembling a concrete essential oil, which is apparently produced during the decomposition of coal tar, by exposure to a red heat|journal=[[Philosophical Transactions of the Royal Society]]|volume=111|pages=209–221|doi=10.1098/rstl.1821.0017|s2cid=97798085}}</ref>
* [[Pierre Jean Robiquet]], [[Joseph Bienaimé Caventou]] and [[Pierre Joseph Pelletier]] isolate [[caffeine]].

==Geography and exploration==
* January 28 – Russian explorer [[Fabian Gottlieb von Bellingshausen]] discovers [[Alexander Island|Alexander I Land]] in Antarctica, later determined to be the world's second-largest uninhabited island.
* December 6 – The [[South Orkney Islands]] are discovered by [[George Powell (sealer)|George Powell]] and [[Nathaniel Palmer]].<ref>{{cite book|author=Headland, Robert K.|title=Chronological list of Antarctic expeditions and related historical events|publisher=Cambridge University Press|year=1989|isbn=978-0-521-30903-5|oclc=185311468}}</ref><ref>{{Cite web|url=http://www.britannica.com/EBchecked/topic/556316/South-Orkney-Islands|title=South Orkney Islands &#124; Location & Facts}}</ref>
* December 15 – The world's first geographical society, the [[Société de géographie]], is established in Paris.
* [[William Parry (explorer)|William Parry]] starts his second voyage to find the [[Northwest Passage]].

==Geology==
* [[Ignaz Venetz]] proposes his [[ice age]] theory.
* [[Pierre Berthier]] discovers [[bauxite]].
* [[Mary Anning]] finds the first ever [[plesiosaur]] fossil at [[Lyme Regis]].

==Mathematics==
* [[Augustin-Louis Cauchy]] gives the first complete presentation of [[calculus]] using limits.

==Medicine==
* [[Charles Bell]] presents a paper to the [[Royal Society]], "On the Nerves, Giving an Account of some Experiments on their Structure and Functions, which led to a New Arrangement of the System", identifying [[Bell's palsy]]; and also publishes his book ''Illustrations of the Great Operations of Surgery: Trepan, Hernia, Amputation, Aneurism, and Lithotomy'' (illustrated by himself).
* [[Jean Marc Gaspard Itard]] publishes ''Traité des maladies d'oreille et de l'audition'' in Paris, a major work on [[otology]].

==Paleontology==
* [[William Buckland]] finds the remains of a [[hyena]]'s den in [[Yorkshire]], containing the bones of [[lion]]s, [[elephant]]s and [[rhinoceros]].

==Physics==
* [[Michael Faraday]] discovers electromagnetic rotation.
* [[Thomas Johann Seebeck]] discovers the [[thermoelectric effect]].
* [[Augustin Fresnel]] shows that light is made up of a traverse wave motion.
* [[John Herapath]] publishes a [[kinetic theory of gases]].

==Technology==
* [[Antide Janvier]] publishes his textbook on the theory and practice of watchmaking, ''Manuel Chronometrique, ou, precis de ce qui concerne le temps, ses divisions, ses mesures, leurs usages, etc.'' in Paris.

==Awards==
* [[Copley Medal]]: [[Edward Sabine]]; [[John Herschel]]<ref>{{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}}</ref>

==Births==
* May 16 – [[Pafnuty Chebyshev]] (died [[1894 in science|1894]]), Russian [[mathematician]].
* May 25 – [[Henri Alexis Brialmont]] (died [[1903 in science|1903]]), [[Limburg (Netherlands)|Limburgish]] [[military engineer]].
* May 26 – [[Amalie Dietrich]] (died [[1891 in science|1891]]), [[Germans|German]] [[naturalist]].
* April 27 – [[Henry Willis]] (died [[1901 in science|1901]]), English organ builder.
* August 16 – [[Arthur Cayley]] (died [[1895 in science|1895]]), English mathematician.
* August 31 – [[Hermann von Helmholtz]] (died [[1894 in science|1894]]), German [[physicist]].
* October 13 – [[Rudolf Virchow]] (died [[1902 in science|1902]]), German [[biologist]].
* November 18 – [[Franz Brünnow]] (died [[1891 in science|1891]]), German [[astronomer]].
* December 21 – [[Samuel Haughton]] (died [[1897 in science|1897]]), [[Irish people|Irish]] scientific [[polymath]].

==Deaths==
* April 20 – [[Franz Karl Achard]] (born [[1753 in science|1753]]), German [[chemist]].
* October 4 – [[Marie-Louise Lachapelle]] (born [[1769 in science|1769]]), French [[midwife]].

==References==
{{reflist}}

[[Category:1821 in science| ]]
[[Category:19th century in science]]
[[Category:1820s in science]]