1821 in science

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

• William Jackson Hooker publishes Flora Scotica; or, A description of Scottish plants.

Chemistry

• John Kidd describes the properties of the substance which he calls naphthaline.^[1]

Exploration

• December 6 – The South Orkney Islands are discovered by George Powell and Nathaniel Palmer.^[2][3]
• William Edward Parry starts his second voyage to find the Northwest Passage.

Geology

• Ignatz 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 lead 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 lions, elephants 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

Births

• May 16 - Pafnuty Chebyshev (died 1894), mathematician.
• May 25 - Henri Alexis Brialmont (died 1903), military engineer.
• April 27 - Henry Willis (died 1901), organ builder.
• August 16 - Arthur Cayley (died 1895), mathematician.
• August 31 - Hermann von Helmholtz (died 1894), physicist.
• October 13 - Rudolf Virchow (died 1902), biologist.
• November 18 - Franz Bronnow (died 1891), astronomer.

Deaths

• April 20 - Franz Karl Achard (born 1753), chemist.
• Marie LaChapelle (born 1769), obstetrician.

References