| 1799–1825 | [maths] | The French mathematician and physicist Pierre-Simon Laplace publishes the five-volume Traité de mécanique céleste/Celestial Mechanics, which applies calculus to the motions of celestial bodies and Isaac Newton's theories of the Solar System to show how its stability is implicit in the law of gravitation. |
| 1800–1850 | USA [consumer products] | A revolution in retail and wholesale trade occurs: specialization transforms the urban retail market, replacing the general store with individual stores for hardware, groceries, dry goods, furnishing, books, tobacco, and so on. Cash-only sales policies are instituted around 1806. |
| 1810–1859 | USA [agriculture] | US cotton production, the vast majority of which is grown in the southern states, rises from 171,000 bales in 1810 to just under 5.4 million in 1859. |
| 1819–1826 | UK [other structures] | Scottish engineer Thomas Telford constructs the 177 m/580 ft Menai suspension bridge over the Menai Straits between Bangor, Wales and the island of Anglesey. The first modern suspension bridge, it uses chains of wrought-iron links suspended from masonry towers at either end. Lacking stiffening girders it is vulnerable to high winds. |
| 1821–1822 | France [thought and scholarship] | French Egyptologist Jean-François Champollion deciphers the Egyptian hieroglyphics on the Rosetta Stone. |
| 1821–1830 | USA, UK, Ireland [statistics and demography] | Emigration to the USA from Britain is 27,489, and from Ireland, 54,338. |
| 1822 | [maths] | French mathematician Augustin-Louis Cauchy formulates the basic mathematical theory of elasticity; he defines stress as the load per unit area of the cross-section of a material, agreeing with Poisson's conclusions of 1811. |
| 1822 | Austria [orchestral music] | The Austrian composer Franz Schubert stops work on his Symphony No. 8 in B minor (D 759), the Unfinished, but completes his Mass in A flat (D 678). He also completes his opera Alfonso und Estrella (D 732). It is first performed in 1854, in Weimar, Germany. In this year, he also writes his Wanderer Fantasy (D 760). |
| 1822 | UK [archaeology] | Mary Anning discovers the first fossil to be recognized as that of a dinosaur – an Iguanodon – in Devon, England. |
| 1822 | UK [churches and temples] | St Pancras Church in London, England, designed by the English architects Henry William Inwood and his father William Inwood, is completed, one of the finest examples of the Gothic Revival style. |
| 1822 | Liberia [colonization] | Liberia, west Africa, is founded as a colony for freed US slaves by the Washington Colonization Society. |
| 27 April 1822 | USA [births and deaths] | Ulysses S Grant, US general who commands the Union army during the last two years of the American Civil War and president 1863–77, born in Point Pleasant, Ohio (–1885). |
| 25 June 1822 | Germany [births and deaths] | E(rnst) T(heodor) A(madeus) Hoffmann, German writer, composer, and painter, dies in Berlin, Germany (46). |
| 8 July 1822 | England, Tuscany [births and deaths] | Percy Bysshe Shelley, English Romantic lyric poet, dies at sea off Livorno, Tuscany, Italy (29). |
| 22 July 1822 | Austria [births and deaths] | Gregor Mendel, Austrian monk and botanist who lays the mathematical foundations of genetics, born in Heinzendorf, Austria (–1884). |
| 25 August 1822 | England, Germany [births and deaths] | William Herschel, German-born English astronomer who discovered Uranus and developed a theory of stellar evolution, dies in Slough, Buckinghamshire, England (83). |
| 23 September 1822 | Portugal [law and government] | A Portuguese constitution is decreed, providing for liberty, legal equality, a single chamber which the king may not dissolve until its period of four years has expired, and a constitutional monarchy. |
| 28 September 1822 | France [births and deaths] | Louis Pasteur, French microbiologist who proves that micro-organisms cause disease and fermentation and develops the process of pasteurization, born in Dole, France (–1895). |
| 12 October 1822 | Brazil, Portugal [decolonization] | Brazil becomes formally independent of Portugal and Dom Pedro is proclaimed Emperor Pedro I. |
| 20 December 1822 | UK [newspapers] | The Sunday Times is founded in London, England, by its parent organization The Times, but with an independent editorial policy. |
