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 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.

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.

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).

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."

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.

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).

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

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.

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.

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 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?

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 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.

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

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

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.

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.

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.

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.

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

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).