Great Hurricane of 1780 — the deadliest Atlantic hurricane on record — kills 20,000 to 30,000 in Caribbean.

William Herschel discovers first binary star, Xi Ursae Majoris.

Abraham Gottlob Werner asserts that all rocks have been deposited by a primordial ocean. This "Neptunian" view is accepted with little question.

Mozart's opera "Idomeneo" premieres in Munich.

Painting by Henry Fuseli: The Nightmare shows a woman in deep sleep with her arms thrown below her, and with a demonic and apelike incubus crouched on her chest. The painting's dream like and haunting erotic evocation of infatuation and obsession was a huge popular success. After its first exhibition, at the 1782 Royal Academy of London, critics and patrons reacted with horrified fascination and the work became widely popular, to the extent that it was parodied in political satire, and an engraved version was widely distributed. In response, Fuseli produced at least three other versions.

Immanuel Kant publishes Critique of Pure Reason, a fundamental work of modern philosophy.

Pierre François André Méchain discovers M80 (globular cluster in Scorpio).

Johan Carl Wilcke introduces the concept of SPECIFIC HEAT.

Coloumb's Théorie des machiones simple (Theory of simple machines) is a study of friction.

Britain signs agreement recognizing U.S. independence.

Congress approves Great Seal of U.S. and the eagle as its symbol.

Joseph and Jacques Montgolfier make first public balloon flight.

Earthquakes ravage Calabria in Italy, killing 30,000.

The amateur British astronomer John Michell proposes the theoretical idea of an object massive enough that its gravity would prevent even light from escaping (which has since become known as a black hole). He realizes that such an object would not be directly visible, but could be identified by the motions of a companion star if it was part of a binary system. A similar idea was independently proposed by the Frenchman Pierre-Simon Laplace in 1795.

Horace-Bénédict de Saussure's Essais sur l'hygromé (Essay on measuring humidity) describes how to construct a hygrometer from human hair that can measure relative humidity.

Painting by Jacques-Louis David: Oath of the Horatii (French: Le Serment des Horaces), is now on display in the Louvre in Paris. The painting immediately became a huge success with critics and the public, and remains one of the best known paintings in the Neoclassical style. It depicts a scene from a Roman legend about a dispute between two warring cities, Rome and Alba Longa. Instead of the two cities sending their armies to war, they agree to choose three men from each city; the victor in that fight will be the victorious city. From Rome, three brothers from a Roman family, the Horatii, agree to end the war by fighting three brothers from a family of Alba Longa, the Curiatii. The three brothers, all of whom appear willing to sacrifice their lives for the good of Rome, are shown saluting their father who holds their swords out for them. Aside from the three brothers depicted, David also represents, in the bottom right corner, a woman crying whilst sitting down. She is Camilla, a sister of the Horatii brothers, who is also betrothed to one of the Curiatii fighters, and thus she weeps in the realisation that, in any case, she will lose someone she loves. The painting is considered a paragon of neoclassical art.

John Jay becomes first U.S. Secretary of State.

Russian trappers established a colony on Kodiak Island, Alaska.

Treaty of Paris ratified, officially ending the American Revolutionary War

Congress of the Confederation ratifies the Treaty of Paris on January 14, 1784, formally ending the Revolutionary War.

John Wesley charters Methodist Church.

Historian and naturalist Cosimo Alessandro Collini publishes a description of the first known pterosaur.

George Atwood accurately determines the acceleration of a free-falling body.

Charles Willson Peale establishes a natural history museum in Philadelphia, one of the first successful American museums.

First balloon flight across English Channel (Jean-Pierre Blanchard and John Jeffries).

French balloonists Jean-François Pilatre de Rozier and Jules Romain are killed when their Royal Balloon crashes near Boulogne, France, June 15, 1785, in what is considered the first aerial disaster.

Napoleon Bonaparte (16) graduates from the military academy in Paris (42nd in a class of 51).

Lazzaro Spallanzani performs artificial insemination on a dog.

In his Theory of the Earth, James Hutton explains the principle of uniformitarianism: all geological features can be explained by changes that can be observed now, taking place over very long periods of time.

Couloumb makes precise measurements of the forces of attraction and repulsion between charged bodies and between magnetic poles, using a torsion balance, demonstrating conclusively that electric charge and magnetism obey inverse-square laws like that of gravity. He also discovers that electrically charged bodies discharge spontaneously. In the 20th century, it is found that cosmic radiation is responsible for this discharge.

Mozart's opera, The Marriage of Figaro, premieres in Vienna.

Frederick the Great, King of Prussia, dies.

Twining's Tea creates a logo that is still in use today, making it the world's oldest, continuous use logo. The founder of Twinings was Thomas Twining from Painswick, Gloucestershire in England. He opened Britain's first known tea room at No. 216 Strand, London, in 1706; it still operates today.

Federalist Papers published, calls for ratification of Constitution. The Federalist (later known as The Federalist Papers) is a collection of 85 articles and essays written (under the pseudonym Publius) by Alexander Hamilton, James Madison, and John Jay promoting the ratification of the United States Constitution. Seventy-seven were published serially in the Independent Journal and the New York Packet between October 1787 and August 1788. A compilation of these and eight others, called The Federalist: A Collection of Essays, Written in Favour of the New Constitution, as Agreed upon by the Federal Convention, September 17, 1787, was published in two volumes in 1788 by J. and A. McLean. The collection's original title was The Federalist; the title The Federalist Papers did not emerge until the 20th century. This book should be carefully read by anyone with an interest in American democracy.

Constitutional convention opens at Philadelphia, George Washington presiding.

Austrian emperor Jozef II bans children under 8 from labor.

Herschel discovers Enceladus, a moon of Saturn, and Titania and Oberon, moons of Uranus.

Jacques-Alexandre Charles shows that different gases expand by the same amount for a given rise in temperature (Charles Law).

Thomas Jefferson publishes Notes on the State of Virginia refuting Buffon's claim that America's harsh, moist climate stunts the growth of its inhabitants. He also addresses the issue of race, describing Native Americans favorably, but African slaves unfavorably.

Painting by Francisco de Goya: Manuel Osorio Manrique de Zúñiga, also known as Goya's Red Boy. Vicente Joaquin Osorio de Moscoso y Guzmán (1756–1816), Count of Altamira, had hired Goya for several family portraits. Altamira held many titles and was also a director of the Banco de San Carlos. In 1786, after painting several portraits of the court, Goya was nominated painter to Charles III. This painting, from 1787–88, is of Altimira's youngest son, Manuel, who was born in April 1784 and died at age eight on June 12, 1792.

Maryland votes (December 23) to cede a ten-square-mile area for District of Columbia.

New York City becomes first capital of US.

Captain Arthur Phillip forms English colony at Sydney, Botany Bay, New South Wales, Australia.

Kant publishes Critique of Practical Reason.

Juan-Bautista Bru mounts the first relatively accurate fossil reconstruction of an extinct animal from South America. Georges Cuvier classifies it as a giant sloth.

US Congress passes Federal Judiciary Act, creating a six-person Supreme Court.

Bourbon Whiskey is first created by Elijah Craig in Bourbon, Kentucky.

George Washington becomes the first president of the United States.

Fletcher Christian leads Mutiny on HMS Bounty and Captain William Bligh. Mutineers from the Bounty settle on Pitcairn Island.

Former slave Olaudah Equiano publishes his memoirs, and he travels in Britain lecturing against slavery.

The fall of the Bastille marks the beginning of the French Revolution.

Gilbert White's The Natural History and Antiquities of Selborne, a series of notes about animal and plant life in Selborne, England, is the first recognizable work of ecology. It goes through about 300 different editions and is still in print today.

Johann Wolfgang Goethe's Versuch, die Metamorphose der Pflanzen zu erklären (Attempt to explain the metamorphosis of plants) claims incorrectly that all plant structures are modified leaves, but clearly espouses evolution.

French polymath Antoine Lavoisier publishes a paper on French geology defining peacefully deposited pelagic sediments and violently deposited littoral sediments. He argues that these sediments illustrate a fluctuating sea level on an ancient planet.

The French chemist Antoine-Laurent de Lavoisier definitively states the Law of Conservation of Mass (although others had previously expressed similar ideas, including the ancient Greek Epicurus, the medieval Persian Nasir al-Din al-Tusi and the 18th Century scientists Mikhail Lomonosov, Joseph Black, Henry Cavendish and Jean Rey), and identifies (albeit slightly incorrectly) 23 elements which he claims can not be broken down into simpler substances.