The US flag is modified to have twenty-three stars, reflecting the addition of two new states: Alabama and Maine.

Debate over slavery in the US heats up; The Missouri Compromise admits Maine into the Union as a free state, with Missouri to enter the next year as a slave state. Slavery is banned north of the 36 30' line of latitude in the Louisiana Territory.

Missouri Compromise Missouri is admitted to the Union as a slave state, Maine as a free state. Slavery is forbidden in any subsequent territories north of latitude .

The first Christian missionaries arrived in the Hawaiian Islands.

André-Marie Ampère formulates one of the basic laws of electromagnetism, the right-hand rule for the influence of an electric current on the magnet and demonstrates that two wires that are carrying an electric current will attract or repel each other, depending on whether the occurrence are in opposite where the same directions.

Dominique-François Arago discovers the magnetic effect of electricity passing through a copper wire, demonstrating that iron is not necessary for magnetism.

Augustin-Jean Fresnel invents the so-called Fresnel lens, a lens used in lighthouses.

The science of electrodynamics is born with the announcement of Hans Christian Ørsted's discovery of electromagnetism.

The Arithmometer was the first commercially successful mechanical calculator patented

Painting by John Constable: The Hay Wain depicts a rural scene on the River Stour between the English counties of Suffolk and Essex. It hangs in the National Gallery in London and is regarded as "Constable's most famous image" and one of the greatest and most popular English paintings. Painted in oils on canvas, the work depicts as its central feature three horses pulling what in fact appears to be a wood wain or large farm cart across the river. Willy Lott's Cottage, also the subject of an eponymous painting by Constable, is visible on the far left. The scene takes place near Flatford Mill in Suffolk, though since the Stour forms the border of two counties, the left bank is in Suffolk and the landscape on the right bank is in Essex.

Michael Faraday invents the electric motor and generator.

The US flag is modified to have twenty-four stars, reflecting the addition of one new state: Missouri.

Slave Revolt: South Carolina Freed slave Denmark Vesey attempts a rebellion in Charleston. Thirty-five participants in the ill-fated uprising are hanged.

Omalius d'Halloy names the Cretaceous System, after massive chalk deposits. This time period will later be identified with the last dinosaurs and the first flowering plants.

William Conybeare and William Phillips name the Carboniferous System, a period associated with coal deposits. This time period will also become known as the Mississippian and Pennsylvanian Periods in the United States.

Charles Babbage takes first steps in the construction of machines that would compute numbers

Nic phore Ni pce abandons silver halide photography as hopelessly impermanent and tries using thin coatings of Bitumen of Judea on metal and glass. He creates the first fixed, permanent photograph, a copy of an engraving of Pope Pius VII, by contact printing in direct sunlight without a camera or lens. It is later destroyed; the earliest surviving example of his "heliographic process" is from 1825.

Slavery is abolished in Chile.

Physicist Michael Faraday (1791-1867) describes the liquification of chlorine in On fluid chlorine. Faraday finds that gasses of certain kinds, when kept under constant pressure, will condense until they cool. This latter discovery ushers in the beginning of mechanical methods of refrigeration.

Small-scale drilling for oil begins at Baku, a Russian port city on the west coast of the Caspian Sea, now the capital of Azerbaijan. The drilling marks the beginning of the modern petroleum industry, and by 1900 nearly half the world's oil will come from the Baku oil fields.

Mexico outlaws slavery. This decision creates the incentive for Anglo Texans to fight for independence in 1835-1836.

Mexico becomes a republic, three years after declaring independence from Spain.

Réflexions sur la puissance motrice du feu (On the motive power of fire) by Nicolas Léonard Sadi Carnot shows that work is done as heat passes from a high temperature to a low temperature; defines work; hints at the second law of thermodynamics; and suggests internal combustion engines.

Nic phore Ni pce makes the first durable, light-fast camera photograph, similar to his surviving 1826-1827 photograph on pewter but created on the surface of a lithographic stone. It is destroyed in the course of subsequent experiments.

The Diary of Samuel Pepys is published in Britain. Pepys (1633-1703) had been a secretary of the Admiralty, a member of Parliament, and President of the Royal Society, and his Diary presents an important and entertaining picture of London during the Restoration period.

John Quincy Adams becomes the sixth president of the United States.

The Erie Canal (from Albany to Buffalo, New York) opens on October 26, connecting the Midwestern U.S. with the Atlantic Ocean, via the Great Lakes, and stimulating the development of Fort Dearborn (know today as Chicago), Cleveland and Columbus Ohio, and upstate New York cities like Rochester, Syracuse and Little Falls.

The first passenger steam railway opens, between Stockton and Darlington, England.

The Last of the Mohicans, by James Fenimore Cooper, is published.

Photograph by Joseph Ni pce: View from the Window at Le Gras, the world's first permanent photograph.

The first photographic images produced by Joseph-Nicéphore Ni pce

Theory of systems of rays by William Rowan Hamilton is a unification of the study of optics through the principle of "varying action". It contains his correct prediction of conical refraction. When his prediction is verified, he becomes a well-known and is knighted.

While studying the behavior of fluids under a microscope, botanist Robert Brown (1773-1858) discovers what is today called "Brownian motion".

(no entry for this year)

Chemist James Smithson (1765-1829) bequeaths £100,000 to found the Smithsonian Institution in Washington, D.C. The Institution will be founded in 1846.

Andrew Jackson becomes the seventh president of the United States.

Slavery abolished in Mexico.

Jules Desnoyers names the Quaternary System, a time in which humans have lived.

Gustave-Gaspard Coriolis coins the term KINETIC ENERGY in On the calculation of mechanical action.

Joseph Henry shows that passing an electric current through a wire wrapped into coils produces a greater magnetic field than is produced when that same current is passed through a straight wire, and that an insulated wire wrapped around an iron core can produce a powerful electromagnet.

The first steam locomotive to operate on a U.S. railroad begins service between Carbondale and Honesdale, Pennsylvania. The engine, "The Stourbridge Lion", has been imported from the Stephenson Engine Works in London.