Painting by Eugène Delacroix: Liberty Leading the People (French: La Liberté guidant le peuple) commemorates the July Revolution of 1830, which toppled King Charles X of France. A woman personifying the concept and the Goddess of Liberty leads the people forward over a barricade and the bodies of the fallen, holding the flag of the French Revolution — the tricolour flag, which remains France's national flag — in one hand and brandishing a bayonetted musket with the other. The figure of Liberty is also viewed as a symbol of France and the French Republic known as Marianne. By the time Delacroix painted Liberty Leading the People, he was already the acknowledged leader of the Romantic school in French painting.

On April 6, the Church of Jesus Christ of Latter-Day Saints is founded by Joseph Smith Jr. (1805-1844), in Fayette, New York. In Palmyra, New York, The Book of Mormon is published for the first time; Smith has translated it, he says, from golden tablets he found buried near Palmyra.

The first wagon trains to cross the Rocky Mountains arrived in California.

The U.S. Congress passes the Indian Removal Act.

The world's population tops 1,000,000,000 (it had been roughly 750 million only 50 years earlier).

Charles Lyell's multi-volume Principles of Geology appear (between 1830 amd 1833), advancing the theory of uniformitarianism, i.e., the view that geological formations are explainable in terms of forces and conditions observable at present.

Georg Goldfuss announces that he sees "hairs" on a pterosaur fossil. This outlandish assertion will be supported by later finds.

The first edition of Birds of America, by the painter and ornithologist John James Audubon (1785-1851), appears.

Nat Turner leads a slave rebellion in Southampton, Virginia, killing at least 57 whites. Hundreds of black slaves are killed in retaliation.

Alabama makes it illegal for enslaved or free blacks to preach.

In Boston, William Lloyd Garrison founds the abolitionist newspaper, The Liberator, signaling a dramatic shift in the antislavery movement. In the previous decades, it had centered in the South and favored a combination of compensated emancipation and colonization of freed slaves back to Africa. In the 1830s, the abolitionist movement becomes the dominant voice among antislavery advocates. Abolitionists demand the immediate end to slavery, which they consider to be a moral evil, without compensation to slaveowners.

Nat Turner, a literate slave who believes he is chosen to be the Moses of his people, instigates a slave revolt in Virginia. He and his followers kill 57 whites, but the revolt is unsuccessful and up to 200 slaves are killed. After an intense debate, the Virginia legislature narrowly rejects a bill to emancipate Virginia's slaves. The widespread fear of slave revolts, compounded by the rise of abolitionism, leads legislatures across the South to increase the harshness of their slave codes. Also, expressions of anti-slavery sentiment are suppressed throughout the South through state and private censorship.

North Carolina enacts a statute that bans teaching enslaved people to read and write.

Slave Revolt: Virginia Slave preacher Nat Turner leads a two-day uprising against whites, killing about 60. Militiamen crush the revolt then spend two months searching for Turner, who is eventually caught and hanged. Enraged Southerners impose harsher restrictions on their slaves.

Charles Darwin joins the crew of the HMS Beagle as the ship's naturalist. The Beagle plans a two-year voyage to map the coast of South America. This turns out to be a five-year trip.

Patrick Matthew publishes On Naval Timber and Arboriculture with an appendix describing what Charles Darwin will later name natural selection. After becoming aware of Matthew's hypothesis, Darwin will acknowledge it in a reprint of On the Origin of Species.

Robert Brown published his observations reporting the discovery and widespread occurrence of nuclei in cells.

Independently, Michael Faraday and Joseph Henry discover that electricity can be induced by changes in a magnetic field (electromagnetic induction), a discovery leading to the first electric generators.

Encouraged by Cambridge professor William Whewell, the Royal Society of London commissions reports of manuscripts received. This move will later be cited as the beginning of the peer-review process.

In Vienna, kitchen apprentice Franz Sacher, 16, creates what comes to be known as Sachertorte, for a dinner in honor of Austria's Prince Klemens Wenzel von Metternich.

Oberlin College is founded in Ohio. It admits African-Americans. By 1860, one third of its students are black.

Electric telegraph invented by Samuel Morse.

Gideon Mantell finds the first fossil Hylaeosaurus, an ankylosaur. He will formally name it the following year, making it the third identified dinosaur species.

The American Anti-Slavery Society is established in Philadelphia.

The British Parliament abolishes slavery in the entire British Empire.

Solicitor André Brouillet discovers a reindeer bone with an engraved illustration of two female deer in Chaffaud Cave. He assumes the carving was made by the Celts. Later research will show the artwork to be about 13,000 years old.

The first volume of the five-volume Recherches sur les poissons fossiles (Researches on Fossil Fishes) by Jean-Louis-Rodolphe Agassiz is published.

The English term SCIENTIST is coined by the philosopher William Whewell (1794-1866 ), during a meeting of the British Association for the Advancement of Science.

In correspondence, Michael Faraday and William Whewell introduce the terms ELECTRODE, ANODE, ION, CATHODE, ANION, CATION, ELECTROLYTE, and ELECTROLYSIS.

South Carolina bans the teaching of blacks, and slave or free, in its borders.

Federal troops are ordered to put down a riot by workers along the Chesapeake and Ohio Canal. It is the first time federal troops have been used to settle a labor battle in the United States.

Based on a vertebrae and other fragments from Alabama, anatomist Richard Harlan identifies Basilosaurus as a fossil reptile. It will later be identified as a fossil whale.

Friedrich von Alberti names the Triassic System. This time period will later by identified with the first dinosaurs.

Mathematician Carl Friedrich Gauss (1777-1855) shows that the origin of the Earth's magnetic field must lie deep inside the Earth. He makes use of the measurements of the magnetic field made by the physicist Paul Erman in 1828.

Painting by Caspar David Friedrich: The Stages of Life (German: Die Lebensstufen) is an allegorical oil painting completed just five years before his death. This picture, like many of his works, forms a meditation both on his own mortality and on the transience of life. The painting is set on a sea shore and shows in the foreground an aged man with his back turned to the viewer, walking towards two adults and two children on a hilltop overlooking a harbour. The figures are echoed by five ships shown in the harbour, each at a different distance from the shore, an allegorical reference to the different stages of human life, to the end of a journey, to the closeness of death. The figures have been identified as Friedrich and his family. The aged man is the artist himself, the small boy is his young son Gustav Adolf, the young girl is his daughter Agnes Adelheid, the older girl is his daughter Emma, and the man in the top hat is his nephew Johann Heinrich.}The Stages of Life (German: Die Lebensstufen) is an allegorical oil painting of 1835 by the German Romantic landscape painter Caspar David Friedrich. Completed just five years before his death, this picture, like many of his works, forms a meditation both on his own mortality and on the transience of life. The painting is set on a sea shore and shows in the foreground an aged man with his back turned to the viewer, walking towards two adults and two children on a hilltop overlooking a harbour. The figures are echoed by five ships shown in the harbour, each at a different distance from the shore, an allegorical reference to the different stages of human life, to the end of a journey, to the closeness of death. The figures have been identified as Friedrich and his family. The aged man is the artist himself, the small boy is his young son Gustav Adolf, the young girl is his daughter Agnes Adelheid, the older girl is his daughter Emma, and the man in the top hat is his nephew Johann Heinrich.

Texas declares its independence from Mexico. In its constitution as an independent nation, Texas recognizes slavery and makes it difficult for free blacks to remain there.

Southern states expel abolitionists and forbid the mailing of antislavery propaganda.

The first volume of La Dèmocracie en Amèrique (Democracy in America), by Alexis de Tocqueville (1805-1859), is published in France. Tocqueville, a historian and politician and member of the French aristocracy, writes about the American people and their institutions, based on his 9 months of travels through the United States and eastern Canada in 1831-1832.

While serving as scientific officer on the HMS Beagle, Charles Darwin visits the Galapagos Islands. He observes that the many varieties of finches on the islands seem to have developed from a common ancestor found on the mainland of South America.

Adam Sedgwick names the Cambrian System, recognizing the first rich assemblage of fossils in the rock record. Roderick Murchison names the Silurian System. He believes (not entirely accurately) that the Silurian predates the fossils of land plants, and consequently any economically valuable coal seams. Murchison and Sedgwick will later develop a bitter priority dispute over these systems.

Gustave-Gaspard Coriolis's Mémoire sur les equations du mouvement relatif des sytèms de corps (Memoir on the equations of relative movement of systems of bodies) describes the Coriolis effect: the deflection of a moving body caused by Earth's rotation. The Coriolis effect is important in the study of wind. However, the claim that the Coriolis effect determines the direction water rotates when going down a drain is a myth.

Painting by : View from Mount Holyoke, Northampton, Massachusetts, after a Thunderstorm, commonly known as The Oxbow, is a seminal landscape painting by Thomas Cole, founder of the Hudson River School. The painting depicts a Romantic panorama of the Connecticut River Valley just after a thunderstorm. It has been interpreted as a confrontation between wilderness and civilization.

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

Davy Crockett killed, as Texans are defeated by the Mexican army at the Alamo.

In Paris, the Arc de Triomphe is completed. The arch was ordered built by Napoleon in 1806.

Texas gains independence from Mexico after winning the battle of San Jacinto.

Mappa Selenographica, a map of the moon's surface, is produced by the astronomers Wilhelm Beer (1797-1850) and Johann Heinrich von Mädler (1794-1874). The two will also be the first to map Mars.

Henry Riley and Samuel Stutchbury name Thecodontosaurus, the fourth named dinosaur species.

Elements of Botany, by the naturalist Asa Gray (1810-1888), is published. It is the first botanical textbook.

German biologist Theodor Schwann discovers the enzyme pepsin — the first known animal enzyme. He reports the discovery in Über das Wesen der Verdauungsprozesses (On the essence of digestion).

John Frederic Danielle invents the Daniell cell, the first reliable source of electric current, based on the interactions of copper and zinc.

Twice-told Tales, by Nathaniel Hawthorne, is published and is an immediate best-seller.

Daguerreotype by Louis Daguerre: Still life with plaster casts is the earliest, reliably dated daguerreotype.

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

Martin Van Buren becomes eighth president of the United States.

William IV, King of Great Britain, dies.

Charles Darwin formulates the theory of natural selection to explain evolution. Fearful of the reaction his theory will cause, he delays publishing.

Hermann von Meyer names Plateosaurus, the fifth named dinosaur species.

Louis Agassiz presents the theory of the Ice Age at a meeting of the Swiss Society of Natural Sciences. The shocked audience reacts with hostility.

Mathematician Semèon Denis Poisson (1781-1840) publishes Recherches sur la Probabilitè des Jugements. Poisson's book described what is now known as the Poisson Distribution, for the first time.

The Seraphim and Other Poems, by Elizabeth Barrett Browning (1806-1861), is published.

Daguerreotype by Louis Daguerre: The earliest reliably dated photograph of people, taken one spring morning in 1838 from the window of the Diorama, where Daguerre lived and worked. It bears the caption huit heure du matin (8 a.m.). Though it shows the busy Boulevard du Temple, the long exposure time (about ten or twelve minutes) meant that moving traffic cannot be seen; however, the bootblack and his customer at lower left remained still long enough to be distinctly visible. The building signage at the upper left shows that the image is laterally (left-right) reversed, as were most daguerreotypes.

Coronation of Victoria as queen of Great Britain.

M. J. Schleiden and T. Schwann develop the cell theory. Schleiden notes nucleoli within nuclei.

Chemist Jöns Jakob Berzelius (1779-1848) shows that the presence of iron is what enables blood to absorb as much oxygen as it does.

The word PROTEIN first appears in the chemical literature in a paper by G. J. Mulder. The term, however, was invented by J. J. Berzelius.

Voices of the Night, the first book of poems by Henry Wadsworth Longfellow (1807-1882), is published.

La Amistad was a 19th-century two-masted schooner, owned by a Spaniard living in Cuba. It became renowned in July 1839 for a slave revolt by Mende captives, who had been enslaved in Sierra Leone, and were being transported from Havana, Cuba to their purchasers' plantations. The African captives took control of the ship, killing some of the crew and ordering the survivors to sail the ship to Africa. The Spanish survivors secretly maneuvered the ship north, and La Amistad was captured off the coast of Long Island by the brig USS Washington. The Mende and La Amistad were interned in Connecticut while federal court proceedings were undertaken for their disposition. The owners of the ship and Spanish government claimed the slaves as property; but the US had banned the African trade and argued that the Mende were legally free. Because of issues of ownership and jurisdiction, the case gained international attention. Former president John Quincy Adams argued on behalf of the slaves when the appeal was brought before the U.S. Supreme Court, which eventually determined the Africans to be free men. The case became a symbol in the United States in the movement to abolish slavery.

Sultan Abdulmecid I implemented the Tanzimat reforms in an attempt to modernize the Ottoman Empire and strengthen it against European powers. The reforms included changes to the legal system, education, and the military, and were influenced by western ideas.

In response to the British opium trade, Lin Zexu wrote a letter to Queen Victoria, urging her to end the opium trade: We find that your country is sixty or seventy thousand li from China. Yet there are barbarian ships that strive to come here for trade for the purpose of making a great profit. The wealth of China is used to profit the barbarians. That is to say, the great profit made by barbarians is all taken from the rightful share of China. By what right do they then in return use the poisonous drug to injure the Chinese people? Even though the barbarians may not necessarily intend to do us harm, yet in coveting profit to an extreme, they have no regard for injuring others. Let us ask, where is your conscience? The letter to the Queen never reached her. Belatedly, it was delivered and published in The Times of London.

Lin Zexu was a Chinese scholar-official of the Qing dynasty best known for his role in the First Opium War of 1839 42. In March 1839, Lin arrived in Guangdong Province to take measures that would eliminate the opium trade. He was a formidable bureaucrat known for his competence and high moral standards, with an imperial commission from the Daoguang Emperor to halt the illegal importation of opium by the British. Upon arrival, he made changes within a matter of months. He arrested more than 1,700 Chinese opium dealers and confiscated over 70,000 opium pipes. He initially attempted to get foreign companies to forfeit their opium stores in exchange for tea, but this ultimately failed. Lin resorted to using force in the western merchants' enclave. A month and a half later, the merchants gave up nearly 1.2 million kg (2.6 million pounds) of opium. Beginning 3 June 1839, 500 workers laboured for 23 days to destroy it, mixing the opium with lime and salt and throwing it into the sea outside of Humen Town. Lin composed an elegy apologising to the gods of the sea for polluting their realm.

The First Opium War between Britain and China occurs between 1839 and 1842, triggered when Chinese officials attempt to prevent the sale of narcotics (opium) to the Chinese people by the British East India trading Company. The British respond by bringing in gunboats and shelling Chinese coastal cities.

The process of vulcanization, developed by Charles Goodyear, makes possible the commercial use of rubber.

Czech scientist Jan Evangelista Purkyně (also written Johannes Evangelist Purkinje) coins the word PROTOPLASM to describe the contents of a cell.

Roderick Murchison and Adam Sedgwick name the Devonian System.

The English scientist Michael Faraday concludes from his work on electromagnetism that, contrary to scientific opinion of the time, the divisions between the various kinds of electricity are illusory. He also establishes that magnetism can affect rays of light, and that there is an underlying relationship between the two phenomena.