Anna, the Duchess of Bedford (1788-1861), introduces the ritual of afternoon tea in Britain, although tea has been available in England since the late 1600s.

The polka makes its U.S. debut, introduced by the ballerina Fanny Elssler (1810-1884), who had brought the dance to Paris in 1834.

The saxophone is invented in Belgium, by the 26-year old instrument maker Antoine Joseph Sax (1814-1894).

Alexandre-Edmond Becquerel shows that light can initiate chemical reactions that produce an electric current.

First American patent issued in photography to Alexander Wolcott for his camera.

The first postage stamp, called the "Penny Black" and bearing the image of Queen Victoria, is issued in England.

The oil-immersion microscope is invented by Giovanni Battista Amici (1786-1863), a former professor of mathematics who is now the director of the observatory at the Royal Museum in Florence, and an astronomer to the Grand Duke of Tuscany. The objective lens of this microscope is immersed in a drop of oil which sits on top of the object under study; this helps to minimize aberrations caused by the light source.

William Henry Harrison becomes ninth president of the United States; dies one month after inauguration.

The Berlin Zoo opens, when Friedrich Wilhelm IV, the King of Prussia, donates his pheasant gardens and exotic animal colection to the citizens of Berlin.

The New York State Fair is held for the first time, in Syracuse, New York. The Fair is the first in the tradition of U.S. state fairs with agricultural and domestic themes.

Self-Reliance, by Ralph Waldo Emerson (1803-1882) [essay II in Essays: First Series] is published.

The first novel in the series called "Leatherstocking Tales", The Deerslayer, by James Fennimore Cooper (1789-1851), is published

In London, the periodical Punch begins publication.

The U.S.S. Creole, a ship carrying slaves from Virginia to Louisiana, is seized by the slaves on board and taken to Nassau, where they are free.

John Tyler becomes tenth president of the United States.

The first centralized government bureau of statistics is founded in Belgium by the mathematician Lambert Adolphe Jacques Quetelet (1781-1840).

Roderick Murchison names the Permian System.

William Smith's nephew John Phillips formally proposes the geologic eras Paleozoic, Mesozoic and Cainozoic (Cenozoic).

Charles Thomas Jackson (1805-1880) discovers the anesthetic properties of ether.

William Henry Talbot patents the Calotype process, the first negative-positive process making possible the first multiple copies.

Henry Fox Talbot introduces his patented calotype (or "talbotype") paper negative process, an improved version of his earlier process that greatly reduces the required exposure time.

In Paris, street lights made from arc lamps are demonstrated.

In May, Edgar Allan Poe's (1809-1849) story "The Masque of the Red Death" appears in Graham's Magazine.

Frederick Douglass leads a successful campaign against Rhode Island's proposed Dorr Constitution, which would have continued the prohibition on black male voting rights.

In Prigg v. Pennsylvania, the U.S. Supreme Court upholds the Fugitive Slave Law of 1793, stating that slaveowners have a right to retrievetheir "property." In so doing, the court rules that Pennsylvania's anti-kidnapping law is unconstitutional. At the same time, the Supreme Court declares that enforcement of the Fugitive Slave Lawis a federal responsibility in which states are not compelled to participate. Between 1842 and 1850, nine Northern states pass new personal liberty laws which forbid state officials from cooperating in the return of alleged fugitive slaves and bar the use of state facilities for that purpose.

Slavery is abolished in Uruguay.

The Virginia Legislature votes against abolishing slavery.

In Commonwealth v. Hunt, a case involving the Boston Journeyman Bootmakers Society, the Chief Justice of the Massachusetts Supreme Court ruled that trade unions are legal. The ruling revises the common law that treated such unions as criminal conspiracies.

The Massachusetts State Legislature enacts a child labor law that limits the working hours of children under 12 years-old to 10 hours per day.

P. T. Barnum lures crowds of thousands to see his "Feejee Mermaid."

Based on Agassiz's Ice Age theory, self-taught science enthusiast Charles MacLaren publishes a newspaper article explaining that substantial ice sheets in the northern hemisphere would have lowered global sea level.

German physician and physicist Julius Robert Mayer is the first to state the law of conservation of energy, noting specifically that heat and mechanical energy are two aspects of the same thing.

On the uniform motion of heat in homogeneous solid bodies, by William Thomson, aka Lord Kelvin (1824-1907), is published. Thomson's concern with the physics of cooling bodies will draw him into debates concerning the age of the Earth. In 1846 he calculates that the Earth can be no more than 100 million years old.

The change in the observed frequency of waves emitted from a source, moving relative to the observer, is described by Christian Johann Doppler (1803-1853). This phenomenon is now known as the Doppler Effect.

In London, The Economist and Sunday News of the World begin publication.

In Dresden, Richard Wagner's opera Der fliegende Holländer is premiered.

Sequoyah, Cherokee Indian leader, creates Cherokee syllabary and develops the first written form of a native North American language.

Congress grants S. F. B. Morse $30,000 to build the first telegraph line (Washington to Baltimore).

John Stuart Mill publishes Logic.

James Prescott Joule determines the mechanical equivalent of heat by measuring the rise in temperature produced in water by stirring it.

Jerome Increase Case, a 24 year-old farmer from Oswego County, New York, introduces the J. I. Case Threshing Machine. The J. I. Case Company will manufacture farm equipment and will become the largest thresher producer in the world.

The first tunnel under the Thames opens on March 25, built by Isambard Kingdom Brunel (1806-1859). {a]The Thames Tunnel{/a} connects Rotherhithe and Wapping, London. Although it was a triumph of civil engineering, the Thames Tunnel was not a financial success. It had cost a fortune to build — £454,000 to dig and another £180,000 to fit out — far exceeding its initial cost estimates. Proposals to extend the entrance to accommodate wheeled vehicles failed owing to cost, and it was only used by pedestrians. It became a major tourist attraction, attracting about two million people a year, each paying a penny to pass through.

In England, the Young Men's Christian Association (YMCA) is founded by George Williams (1821-1905).

The Open Door is an early calotype, included in The Pencil of Nature, the first commercially published book to be illustrated with photographs.

The Pencil of Nature, published in six installments between 1844 and 1846, was the "first photographically illustrated book to be commercially published" or "the first commercially published book illustrated with photographs". It was wholly executed by the new art of Photogenic Drawing, without any aid whatever from the artist's pencil and regarded as an important and influential work in the history of photography. Written by William Henry Fox Talbot and published by Longman, Brown, Green & Longmans in London, the book detailed Talbot's development of the calotype process and included 24 calotype prints, each one pasted in by hand, illustrating some of the possible applications of the new technology. Since photography was still very much a novelty and many people remained unfamiliar with the concept, Talbot felt compelled to insert the following notice into his book: The plates of the present work are impressed by the agency of Light alone, without any aid whatever from the artist's pencil. They are the sun-pictures themselves, and not, as some persons have imagined, engravings in imitation.

In Hartford, Connecticut, dentist Horace Wells (1815-1848) uses nitrous oxide as an anesthetic; he is the first to do so.

Scientific American is founded by Alfred Beach (1826-1896). The first issue is published on August 28. The publication, in newspaper format, presents science for the general reader.

Edgar Allan Poe's "The Raven" appears in the New York Evening Mirror. Poe's collection The Raven and Other Poems is published.

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

Frederick Douglass publishes his autobiography, The Life and Times of Frederick Douglass.

James K. Polk becomes eleventh president of the United States.

Texas is annexed by the United States.

The Irish potato famine begins, one of the century's worst natural disasters. One million citizens starve to death, and one million others emigrate, mostly to the United States

The School of Medicine in Paris creates a gallery of comparative anatomy.

Michael Faraday relates magnetism to light after finding the magnetic field effects the polarization of light in crystals. He proposes that light may be waves of electromagnetism. He also describes the phenomena of diamagnetism and paramagnetism, which he explains in terms of his concept of a magnetic field.

Francis Ronalds invents the first successful camera for continuous recording (the first "movie camera") of the variations in meteorological and geomagnetic parameters over time. A copy of Ronalds' paper describing describing his device maybe obtained HERE.

The bridge spanning the Allegheny River, at Pittsburgh, designed by engineer John Augustus Roebling (1806-1869), opens in May. It is the first wire cable suspension aqueduct bridge in the world.

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

Mexican-American War Defeated, Mexico yields an enormous amount of territory to the United States. Americans then wrestle with a controversial topic: Is slavery permitted in the new lands?

The first professional baseball game is played, in Hoboken, New Jersey.

The Mexican War (1846-48) between the United States and Mexico results in the United States taking possession of California and much of the Southwest, which had been Mexican territory.

The Oregon Treaty delineates border between the United States and Canada.

James Prescott Joule discovers that the length of an iron bar changes slightly when the bar is magnetized.

Nitroglycerine is discovered by chemist Ascanio Sobrero (1811-1870), although he uses to term "pyroglycerine". Because of the risks involved in its production, it will not be manufactured commercially for more than a decade.

The lock-stitch sewing machine is patented by Elias Howe (1819-1867).

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

The North Star, an abolitionist newspaper, begins publication in Rochester, New York. The paper is founded by escaped slave Frederick Douglass (1817-1895), with money he earned as a result of his autobiography.

Liberia is formed as a home for released American slaves.

Missouri bans the education of free blacks.

The Istanbul slave market is abolished.

The Factory Act is passed in Britain. It forbids women and children between the ages of 13 and 18 to work more than 10 hours per day.

The first United States postage stamps are issued

In his Account of a New Anesthetic Agent, obstetrician Sir James Simpson (1811-1870) argues that chloroform, a substance he discovered, is a better anesthetic than nitrous oxide or ether. Simpson has begun to use chloroform as an anesthetic in childbirth.

Über die Erhaltung der Kraft ("On the Conservation of Force"), by Hermann Ludwig von Helmholtz (1821-1894), is published. It articulates what later becomes known as the Conservation of Energy.

The rotary, or "lightning" printing press is patented by Richard March Hoe (1812-1886). It is used first by the Philadelphia Public Ledger.

Painting by Jean Auguste Dominique Ingres: Venus Anadyomene, now held at the Musée Condé, Chantilly, France. It is a female nude of the Venus Anadyomene type, showing the goddess Venus rising from the sea. Ingres began the painting in 1808 during his stay in Rome at the French Academy. The first preparatory drawings showed Venus in the Venus Pudica position, standing and covering her breasts with her hands. The pose was inspired by Botticelli's The Birth of Venus — Ingres visited Florence and the Uffizi in 1805 and could have seen the painting there. A drawing of 1806 then shows the goddess with her arms in the air and her hair in her hands, a pose the artist also used in his 1856 The Source. The painting remained in the planning stages until 1848, when he completed it as a commission from the banker and botanist Benjamin Delessert.

The US flag is modified to have thirty stars, reflecting the addition of one new state: Wisconsin.

Slavery is abolished in old French and Danish colonies.

Karl Marx publishes The Communist Manifesto, which asserts that revolution by the working classes will ultimately destroy capitalism.

Revolution breaks out across much of Europe; the Second Republic is proclaimed in France.

The American Medical Association is founded in Philadelphia, with a mission "to promote the science and art of medicine and the betterment of public health."

An absolute scale of temperatures is proposed by William Thomson (1824-1907). Thomson will become Baron Kelvin of Largs, in 1892, and the scale will come to bear his name.

Armand Hippolyte Louis Fizeau suggests that light from a source of moving away from the observer will be shifted toward the red end of the spectrum, a phenomenon known as redshift. This is closely related to, but not exactly the same as, the Doppler effect.

Edmond Becquerel makes the first full-color photographs, but they are only laboratory curiosities: an exposure lasting hours or days is required and the colors are so light-sensitive that they sometimes fade right before the viewer's eyes while being examined.

The American Association for the Advancement of Science is founded. Joseph Henry (1797-1898), who had been appointed the first secretary of the Smithsonian in 1846, is the first secretary of the AAAS, which is modeled after The British Association for the Advancement of Science. The British Association has been in existence for 17 years.

The American Association for the Advancement of Science is established.

Henry David Thoreau's A week on the Concord and Merrimack Rivers and "Resistance to Civil Government" (often referred to as "Civil Disobedience") are published.

Painting by Gustave Courbet: The Stone Breakers (French: Les Casseurs de pierres) is a work of social realism, depicting two peasants, a young man and an old man, breaking rocks. The painting was first exhibited at the Paris Salon of 1850. It was destroyed during World War II, along with 154 other pictures, when a transport vehicle moving the pictures to the castle of Königstein, near Dresden, was bombed by Allied forces in February 1945.

Charles Lewis Reason becomes the first African-American college instructor when he is hired at predominantly white Free Mission College (later New York Central College) to teach Greek, Latin, French, and mathematics.

Harriet Tubman escapes from slavery and goes on to lead more than 300 slaves to freedom on the underground railroad.

Zachary Taylor becomes twelfth president of the United States.

The California gold rush begins as more than 100,000 people swarm to California to make their fortunes after gold is found there in 1848.

Showmen Moses Kimball and P. T. Barnum purchase the contents of the Peale Museum (established in 1784).

Armand Hippolyte Louis Fizeau measures the velocity of light in error by measuring the time it takes for a beam of light to pass between the teeth of a rotating gear. The light is reflected by a mirror and stopped by the next tooth of the gear. The result, 315,000 km/se4c (196,000 miles/sec), is within 5% of today's accepted value.

In describing Sadi Carnot's theory of heat, published in 1824, William Thomson (1824-1907) uses the term THERMODYNAMICS.

The speed of light is measured by physicist Armand Hippolyte Louis Fizeau (1819-1896) to be approximately 186,000 miles per second.

A unmanned Montgolfier balloon is used to drop bombs on Venice. This is the first time a bombing has been conducted from the air.